WADC TECHNICAL REPORT 59-339 EFFECT OF PRIOR CREEP ON SHORT-TIME MECHANICAL PROPERTIES OF 17-7PH STAINLESS STEEL (RH 950 Condition Compared to TH 1050 Condition) Jeremy V'i Gluck James W. Freeman The University of Michigan Research Institute March, 1959 Materials Laboratory Contract No. AF 33(616)-3368 Supplement No. 3(58-1715) Project Nos, 8(8-7351) and 8(8-7360) Wright Air Development Center Air Research and Development Command United States Air Force Wright-Patterson Air Force Base, Ohio

FOREWORD This report was prepared by the University of Michigan Research Institute under USAF Contract No. AF 33(616)-3368. This contract was conducted under Project 7360, "Materials Analysis and Evaluation Techniques", Task 73604, "Fatigue and Creep of Materials." The work was administered under the direction of the Materials Laboratory, Directorate of Laboratories, Wright Air Development Center, with Lt. W. H. Hill acting as project engineer. This report covers work conducted from January 1, 1958 to March 31, 19590 The research is identified in the records of the University of Michigan Research Institute as Project 2498. WADC TR 59-339

ABSTRACT A study was carried out on the effect of elevated temperature creep exposure on the short-time mechanical properties of 17-7PH stainless steel in the RH 950 condition of heat treatment. The results were correlated with an earlier study of the TH 1050 condition of the alloy. Exposures were conducted for times of 10, 50, or 100 hours either unstressed or at stresses causing up to 2 percent creep deformation at 600~, 800~, or 900~F, Following the exposures, short-time tension, compression, or tension-impact tests were conducted at either room temperature or the temperature of exposure. A substantial loss in ductility was observed in the room temperature tests following the creep-exposures of the RH 950 condition. At either room temperature or 6000F, a substantial Bauschinger effect was observed in the material subjected to 600~F creep-exposure. This caused an increase in the tension yield strength and a decrease in the compression yield strength as the amount of creep was increased. The ultimate strength was also increased following creep-exposure at 6000F, Little change was found in the other mechanical properties as the result of exposure to creep. Compared to the TH 1050 condition, the RH 950 condition was initially stronger and maintained its strength better after creep-exposure, The RH 950 condition had a greater loss in room temperature ductility following 800~ or 900~F exposure than the TH 1050 condition, The changes in properties are believed due principally to an aging reaction caused by the continuation of the precipitation of an aluminum-nickel compound under the influence of stress and/or terrperature, Plastic strain was also a factor as it produced the Bauschinger effect, Any effects due to strain hardening were minor. PUBLICATION REVIEW This report has been reviewed and is approved. FOR THE COMMANDER: Richard R. Kennedy Chief, Metals Branch Materials Laboratory WADC TR 59-339 iii

TABLE OF CONTENTS Page INTRODUCTION..1. l EXPERIMENTAL PROGRAM 2 TEST MATERIAL 3 TEST SPECIMENS 4 TEST EQUIPMENT AND PROCEDURES... EXPERIMENTAL RESULTS 6 BASE PROPERTIES BEFORE CREEP-EXPOSURE 7 Tension Properties. 7 Compression Properties..........8 Tension-Impact Properties..... Hardness... 10 ESTABLISHMENT OF EXPOSURE STRESSES 10 TENSION PROPERTIES AND COMPRESSION PROPERTIES AFTER EXPOSURE- 11 Unstressed Exposure...... Tension Properties.. Compression Properties. 12 Creep Exposure. 13 Room Temperature Tests. 13 Elevated Temperature Tests 15 Effect of Long-Time Creep-Exposure 17 TENSION-IMPACT PROPERTIES AFTER EXPOSURE, 18 Unstressed Exposure..... 18 Room-Temperature Tests 18 Elevated Temperature Tests.... 19 Creep-Exposure...... 19 Room Temperature... 19 Elevated Temperature 21 METALLOGRAPHIC EXAMINATION 21 X-RAY STUDIES 23......... FACTORS GOVERNING PROPERTY CHANGES 27 COMPARISON OF RH 950 AND TH 1050 CONDITION 32 CONCLUSIONS..........35 REFERENCES........37 WADC TR 59-339 iv

LIST OF TABLES Table Page 1. Tensile Data for 17-7PH Alloy (RH 950 Condition). 38 2, Compression Test Data for As-Heat Treated 17-7PH Alloy (RH 950 Condition)......39 3, Tension-Impact Test Data for 17-7PH (RH 950 Condition).,.. 40 4. Rupture and Creep Deformation Data for 17-7PH (RH 950 Condition)....... 41 5. Effect of Unstressed Exposure on Tensile Properties of 17-7PH (RH 950 Condition).,.42 6. Effect of Unstressed Exposure on Compression Properties of 17-7PH (RH 950 Condition).,. 43 7. Effect of Prior Creep Exposure on Room Temperature Tensile Properties of 17-7PH (RH 950 Condition),., 44 8. Effect of Prior Creep Exposure on Room Temperature Compression Properties of 17-7PH (RH 950 Condition). 45 9, Effect of Prior Creep Exposure on Elevated Temperature Tensile Properties of 17-7PH (RH 950 Condition). 46 10, Effect of Prior Creep Exposure on Elevated Temperature Compression Properties of 17-7PH (RH 950 Condition). 47 11. Effect of Unstressed Exposure on Tension-Impact Properties of 17-7PH (RH 950 Condition).. 48 12, Effect of Prior Creep Exposure on Tension-Impact Properties of 17-7PH (RH 950 Condition).,. 49 13. X-Ray Diffraction Data for 17-7PH (RH 950) Before or After Creep Exposure at 800F..... 50 WADC TR 59-339 v

LIST OF ILLUSTRATIONS Figure Page 1. Panel Sampling Scheme for Sheets of 17-7PH Stainless Steel Sheet.... 51 2. Specimen Blank Sampling Schemes for Panels of 17-7PH Stainless Steel Sheet. * * 52 3, Details of Test Specimens (Tension-Impact and Compression Specimens Designed to be Cut from Creep Specimens after Exposure)... 53 4, Effect of Test Temperature on Tensile Properties of 17-7PH (RH 950 Condition) As Heat-Treated.,54 5, Effect of Test Temperature on Compression Yield Strength of As-Treated 17-7PH (RH 950 Condition) 55 6, Effect of Test Temperature on Tension-Impact Properties of 17-7PH (RH 950 Condition) As HeatTreated,... 56 7. Stress-Rupture Time and Stress Time for Creep Deformation Curves for 17-7PH (RH 950 Condition) at 600", 800~, and 900"F, 57 8. Effect of Creep Exposure at 600~F for 331-437 Hours on Room Temperature Tensile Properties of 17-7PH (RH 950).. 58 9. Effect of Unstressed Exposure at 600~, 800~, or 900~F on Room Temperature Tensile Properties and Hardness of 17-7PH (RH 950 Condition).........59 10. Effect of Unstressed Exposure at 600~, 800~, or 900~F on Tensile Properties of 17-7PH (RH 950 Condition) at Exposure Temperature...... 60 11. Effect of Unstressed Exposure on Room Temperature Compression Yield Strength of 17-7PH (RH 950 Condition).......... 61 12, Effect of Unstressed Exposure at 600~, 800~, or 900~F on Compression Yield Strength of 17-7PH (RH 950) at Exposure Temperature.......... 62 WADC TR 59-339 vi

LIST OF ILLUSTRATIONS (Continued) Figure Page 13. Effect of Prior Creep at 600"F on Room Temperature Tension and Compression Properties of 17-7PH (RH 950 Condition).. * 63 14. Effect of Prior Creep Exposure at 800~F on Room Temperature Tension and Compression Properties of 17-7PH (RH 950 Condition).....,. 64 15. Effect of Prior Creep Exposure at 900~F on Room Temperature Tension and Compression Properties of 17-7PH (RH 950 Condition)....... 65 16. Summary of Effect of Prior Creep-Exposure on Room Temperature Tension and Compression Properties of 17-7PH (RH 950)....... *, 66 17. Room Temperature Tensile and Yield Strength of 17-7PH (RH 950) after 600"F Creep-Exposure versus Total Plastic Strain Attained in the Creep-Exposure. 67 18, Summary of Effect of Prior Creep Exposure at 600~, 800~ or 90.0~F on Room Temperature Properties of 17-7PH(TH 1050 Condition)....... 68 19, Effect of Prior Creep Exposure at 6000F on Tension and Compression Properties of 17-7PH (RH 950 Condition) at 600~F.6. 69 20. Effect of Prior Creep Exposure at 800~F on Tension and Compression Properties of 17-7PH (RH 950 Condition) at 800~F... 70 21. Effect of Prior Creep-Exposure at 900~F on Tension and Compression Properties of 17-7PH (RH 950 Condition) at 900~F.....,. 71 22, Summary of Effect of Prior Creep Exposure on Elevated Temperature Tension and Compression Properties of 17-7PH (RH 950).,..... 72 23, Summary of Effect of Prior Creep Exposure at 600~, 800~, or 900~F on Properties of 17-7PH (TH 1050 Condition) at Exposure Temperature,. 73 24, Effect of Long Creep Exposure on Room Temperature Tensile Properties of 17-7PH(RH 950 Condition) —compared with Effects of l00hr Creep-Exposure 74

LIST OF ILLUSTRATIONS (Continued) Figure Page 25, Effect of Unstressed Exposure on Room Temperature Tension-Impact Properties of 17-7PH (RH 950). * 75 26, Effect of Unstressed Exposure on Elevated Temperature Tension-Impact Properties of 17-7PH (RH 950).... 76 27, Effect of Prior Creep Exposure at 600~, 800~, 900~F on Room Temperature Tension-Impact Properties of 17-7PH (RH 950)................ 77 28, Effect of Prior Creep Exposure at 6000F or 900~F on Elevated Temperature Tension-Impact Properties of 17-7PH (RH 950).......... 78 29, 17-7PH Stainless Steel: Condition A (Longitudinal Face). 79 30, 17-7PH Stainless Steel: Condition A (Transverse Face). 79 31, 17-7PH Stainless Steel: Condition RH 950 (Longitudinal Face)...... 79 32, 17-7PH Stainless Steel: Condition RH 950 (Transverse Face).......... 79 33, 17-7PH Stainless Steel: Condition RH 950 Specimen No. 6L-T6; Creep Tested 100 hours at 800~F to 0.94% Deformation (Longitudinal Face)... 79 34, 17-7PH Stainless Steel: Condition RH 950 Specimen No, 6L-T6; Creep Tested 100 hours at 800~F to 0.94% Deformation (Transverse Face)........ 79 35 - 38, Electron Micrographs of 17-7PH Stainless Steel.. 80 39 - 42. Electron Micrographs of 17-7PH Stainless Steel 81 43. Effect of 100hour Exposure Either Unstressed or to OnePercent Creep on Room Temperature Tension or Compression Properties of 17-7PH (RH 950 Condition)..,. 82 WADC TR 59 -339 viii

INTRODUCTION A study of the effect of prior creep-exposure at elevated temperatures on subsequent short-time mechanical properties of typical aircraft structural metals has been conducted for the past three years at the University of Michigan under the sponsorship of the Materials Laboratory, Wright Air Development Center, U. S. Air Force. The research has been carried out under Air Force Contract AF 33(616)-3368 and accompanying Supplemental Agreements. The results of the past research have been presented in a series of reports; each dealing generally with one material. The materials studied have included 2024-T86 Aluminum alloy (Ref. 1), C10OM titanium alloy (Ref. 2) and 17-7PH stainless steel in the TH1050 condition of heat treatment (Ref. 1 and 3), while forthcoming reports will deal with a Ti-16V-2.5A1 titanium alloy and a study of the creepinduced Bauschinger effect in C10OM titanium. The present report is a study of the effects of prior creep on the properties of 17-7PH stainless steel in the RH 950 condition of heat treatment. This treatment which utilizes a refrigeration step, results in tensile and yield strengths of approximately 237,000 and 222,000 psi respectively as compared the corresponding values of 203,000 and 193,000 psi obtained with the TH 1050 treatment. The elongation values for both treatments were approximately 7 to 8 percent. The research thus permitted comparison of the relative stability towards creepexposure of two commonly used heat treatments of a precipitation hardening stainless steel. The purpose behind the studies of various structural metals is to accumulate background information to aid in the formulation of rules for the prediction of creep damage to short time properties. The need for this type of information has become increasingly important as flight vehicle design and performance requirements have progressed to the point where creep conditions are attained during a portion of the operating cycle. Not only is adequate creep strength important to withstand these conditions but the material must retain satisfactory short-time mechanical properties. "Manuscript released by authors April 30, 1939 for publication as a WADC Technical Report". /WADC TR 59-339 1

EXPERIMENTAL PROGRAM Creep-exposure tests of 17-7PH(RH 950) were conducted at the same temperatures studied for the TH1050 condition of this material; 6000, 800~, or 900~F. The test specimens were exposed for time periods of 10, 50, or 100 hours either at no stress or those stresses selected to produce 0.2, 0.5, 1.0 or 2.0 percent creep deformation in the specified time interval. The creep deformation was defined as the deformation occurring between the completion of loading and the end of the test period. Creep deformation, therefore, does not include either the elastic or plastic deformation, if any, during loading. These values were determined, however, and reported for each exposure test. The creep stresses used were those which had been determined to give, on the average, the desired amount of creep. Since the time, temperature, and stress of testing were fixed, the inherent scatter in creep properties caused the actual deformations for some specimens to be greater or less than the desired value. In most cases, the tests run covered the full range of deformations up to 2-percent. Time-elongation data were taken for each creep-exposure test. The deformation data were broken down as follows: Total loading deformation, plastic loading deformation, creep deformation, total plastic deformation (both short-time and creep), and total deformation (all deformation occuring during the application of the load and to the end of the subsequent creep period). Following the exposures, the following tests of mechanical properties were carried out: 1. Tension tests at room temperature and the exposure temperature. 2. Compression tests at room temperature and the exposure temperature. 3. Tension-impact tests at room temperature on specimens exposed 10 or 100 hours at the three test temperatures and at the exposure temperature for specimens exposed for 10 hours at 600~ or 900~F. 4. Hardness determinations on representative tensile specimens. Metallographic and X-ray examination was also made of selected specimens. These properties were generally correlated with the creep d efo rmation. All test specimens were taken from the sheets in the direction WADC. TR 59-339 2

crosswise to the sheet rolling direction. This is the nominally weaker direction of the material. The properties of the specimens subjected to creep-exposure or unstressed exposure were compared to the average properties originally established for as-treated material by a series of duplicate tests intended to define the normal scatter of each property. In order to give more confidence in the test results, duplicate exposure tests were run in a number of instances. TEST MATERIAL Sixteen sheets of 17-7PH precipitation hardening stainless steel were purchased from the Armco Steel Corporation in the early part of 1956. All material received was from Heat No. 55651. The material was supplied in sheets 0.064-inches thick by 36 inches by 120 inches in No. 2D finish and in Condition A. (Condition A consists of annealing at 1925~F followed by air cooling). The sheets were arbitrarily numbered from 1 to 16. The certified chemical analysis furnished for this material follow s: Element Nominal (percent) Actual (percent) Carbon 0.09 Max 0.072 Manganese 1.00 Max 0.55 Phosphorus 0.04 Max 0.018 Sulfur 0. 03 Max 0.011 Silicon 1.00 Max 0.33 Chromium 16.00-18.00 17.03 Nickel 6.50-7.50 7.25 Aluminum 0.75-1.50 1.28 Iron Balance Balance For tests conducted on the TH 1050 condition of this alloy, (Ref. 3) sheets number 1, 2, and 3 were completely consumed, while sheets 4, 5, and 6 were partially consumed. The balance of the untreated specimen blanks from sheets 4, 5, and 6 were treated to the RH 950 condition, while additionalspecimens were prepared from sheets 7 and 8. Heat treatment to the RH 950 condition was carried out at the University using the following sequence on batches consisting of six bundles, each containing six one-inch wide specimen blanks 22 inches long. WADC TR 59-339 3

1. Condition A material heated in a gas-fired furnace for 10 minutes at 17500~F150F; followed by air cooling. 2. 2-hour delay. 3. Refrigeration at -100~F for 8 hours. (This step accomplished in a 36-inch deep stainless steel Dewar Flask containing a saturated acetone-dry ice mixture.) 4. 30-minute delay. 5. Reheat at 950~F~10~F for 1 hour in a recirculating air furnace; followed by air cooling. The time delays employed in steps 2 and 4 were adopted merely for consistency in processing and ease in scheduling. Heat treatment studies carried out by the producer of the material to develop optimum properties (Refs. 4 and 5) showed that delay times were not especially critical. This treatment was different from the TH 1050 treatment with respect to both the times and temperatures employed. In the TH 1050 treatment, the first step was carried out at 14000F for 1-1/2 hours; (this rendered the material susceptible to martensite transformation at room temperature). The material was then cooled from 1400~F in air for 10 minutes (to reach approximately 500~F) and then quenched in 60~F water. The final treatment was carried out for 1-1/2 hours at 1050~F. Further discussion of the differences between the treatments is included in the section on Metallographic Examination (page 21 ). TEST SPECIMENS As mentioned in the section on Test Material, the specimens for tests of 17-7PH (RH 950) were taken from among five sheets of the original sixteen sheets of material that were purchased. The specimens were so chosen to provide a measure of the variation in properties both between sheets and within individual sheets. This necessitated the use of a coding system in order to identify the origin of each test specimen. Records were kept of the blanks included in each heat treatment batch, In so far as is known, the specimens tested represented random choices of test material. The- sampling scheme designed for the 17-7PH stainless steel is illustrated in Figures 1 and 2, Each sheet of material was divided into a number of modules or panels over the length of the sheet. WADC TR 59-339 4

Within each panel the specimen blanks were arranged in a pattern across the width of the sheet. This pattern was of course extended throughout the sheet by the repetition of the panels. All specimen blanks were one-inch wide; the panel widths being 6 to 7 inches. As each strip was sheared, a code number was stamped on it identifying the sheet number, panel number, and specimen position within the panel —in that order. Thus, the specimen labeled 5F-T6 is a tensile specimen taken from strip No. 6 of panel F in sheet 5. The configuration and dimensions of the various test specimens are shown in Figure 3. All the specimens for the mechanical property tests were designed so that they could be machined from the creep specimen following exposure. For the exposure tests themselves, the width of the gage was machined 0.030 inches over the 0.5-inch nominal width. This practice permitted the subsequent tests to be carried out on material subjected to the same machining practice whether the tests be tension, compression, or tension-impact, In addition, this also permitted the measurement of properties to be unaffected by the particular edge effects, if any, associated with the prior exposure of the specimen. For convenience and uniformity in machining the specimens, jigs were constructed so that five or six could be made concurrently. The blanks were milled to rough dimensions and the shoulder radii and gage sections were ground to the finished dimensions. TEST EQUIPMENT AND PROCEDURES Detailed discussion of the development of the test equipment and procedures has been previously given (Refs. 1, 2, and 3) and will not be repeated in the present report. Wherever applicable, ASTM Recommended Practices were adhered to in test procedures, The creep-exposure tests were carried out in individual creeptesting machines with heating provided by a wire-wound resistance furnace fitting over the specimen assembly. Strain measurements were accomplished using a modified Martens optical extensometer system. Tension and compression tests were conducted in a BaldwinSouthwark hydraulic tensile machin'e equipped with a strain pacer. A strain rate of 0. 005 inches per inch per minute was used. A recording extensometer system employing a micro-former strain gage was employed to give a continuous plot of the test results, A special compression testing fixture which included a loading ram and a pair of guideblocks to restrain lateral buckling of the specimen was constructed for use in this investigation, WADC TR 59-339 5

Specimens prepared for metallographic examination were mounted in bakelite and wet ground in rotating laps using a series of silicon carbide papers through 600 mesh, Final polishing was carried out first with fine diamond compound on a rotating lap and then on a Syntron vibratory polisher in an acqueous media of Linde "B" polishing compound. The samples examined optically were etched in Marble's reagent. A number of etchants were tried to prepare the samples for electron microscope examination with the best results being obtained by the use of modified Nital —15% HC1, 5% HNO3, 80% alcohol. For electron microscope examination, collodion replicas were made from the surface of the etched specimens. The replicas were shadowed with palladium to increase contrast and reveal surface contours. Polystyrene latex spheres of approximately 3400 ~ diameter were placed on the replicas prior to shadowing to indicate the angle and direction of shadowing and provide an internal standard for the measurement of magnification, The micrographs reproduced in this report are direct prints from the original negatives; consequently the polystyrene spheres appear black and the shadows appear white. Since the latex spheres are raised on the replica, a phase casting a shadow opposite to that cast by the latex spheres is in relief on the metal specimen; conversely, areas casting shadows in the same direction as cast by the latex spheres are depressions in the surface of the metal specimen and represent a phase that was attacked by the etchant. EXPERIMENTAL RESULTS The results of the exposure tests were tabulated and correlated with respect to the amount of prior creep, the temperature, and the time of exposure. In the tabulations of the test data the specimen is described both by nominal exposure conditions and the actual exposure conditions. The properties of the unexposed material and the material exposed without stress are used as the basis for the evaluation of the effects of prior creep. A consistent trend in the curve of residual properties versus the amount of prior creep was taken as a measure of a significant change in the property in question. In some instances, however, the change was slight and hardly outside the range established for the unexposed material. These instances are discussed where they are encountered. WADC TR 59-339 6

The results are presented in the following order: the base properties of the material and the stress-versus time for creep deformation curves at each test temperature; the unstressed exposure tests; the creep-exposures followed by room temperature tension and compression tests, elevated temperature tension and compression tests, and finally, room temperature and elevated temperature tensionimpact tests. Hardness determinations are discussed with the mechanical property data. The metallographic studies are discussed following the creep-exposure results. BASE PROPERTIES BEFORE CREEP-EXPOSURE Tension Properties. Tension tests at room temperature, 600~, 800~, and 900~F were conducted to establish a measure of the base properties of as-treated 17-7PH in the RH 950 condition. The test data are summarized in Table I and plotted as a function of test temperature in Figure 4. The six tests run at each test temperature consisted of two specimens from each of three sheets of material treated in several different heat treatment batches. Increasing the test temperature caused a drop of about the same order of magnitude in both the ultimate tensile and yield strengths. Ductility values from the 600~F tests were slightly lower than those obtained at room temperature and then increased substantially at 800~ and 900~F. This behavior was similar to that observed for the TH 1050 condition, The room temperature properties developed in this heat by the RH 950 treatment agree well with those reported by the producer (Ref. 5). The agreement in this case was better than that observed previously for the TH 1050 heat treatment (Ref. 1). This is indicated by the following summary of the data from Table 1. Treatment and Test Ult, Tensile Yield Elongation Data Source * Temp(~F) Strength (psi) Strength(psi) (%) RH 950 "DESIGN" Room 236,000 219,000 7 Heat 55651 Room 237,650 222,480 8.2 TH 1050 "DESIGN" Room 200,000 185,000 10 Heat 55651 Room 203,000 193,910 6.7 WADU TR 5b-33(9 7

Treatment and Test Ult. Tensile Yield Elongation Data Source * Temp. (~F) Strength (psi) Strength(psi) (%) RH 950 "DESIGN" 600 190,000 175,000 6 800 170,000 150,000 8 900 142,000 130,000 11 Heat 55651 600 199,000 171,830 7.8 800 166,783 148,000 14.4 900 137,433 121,233 17.9 NOTES:* "DESIGN" - from design curves - Ref. 5, p. 96B Heat 55651 - U. of M. average values from 3 sheets of 0.064-inch sheet. The comparison between the actual values and the "design" values was generally close although the ductility of Heat 55651 in the RH 950 condition became increasingly higher than the "design" values as the test temperature was increased. This was reflected in appreciably lower strengths only at 900~F although at this temperature the variation in the average strengths between the two sources of data was only 7 percent. It appears, therefore, that the tension properties developed in the present material by the RH 950 treatment were in better agreement with the design data than were the properties developed by the TH 1050 condition. Compression Properties. Compression tests were carried out at room temperature, 600~, 800~, and 900~F to establish base properties of 17-7PH stainless steel as-heat treated to the RH 950 condition. The data are tabulated in Table 2 and plotted as a function of test temperature in Figure 5. Increasing the test temperature caused the compression yield strength to decrease, with the temperature dependence quite similar to that previously reported for the tension properties. The compression yield strength was 10-15 percent higher than the tension yield strength and was generally equal to the ultimate tensile strength. In this respect the behavior of the RH 950 condition was different from that of the TH 1050 condition, since in the latter, the room temperature and 600~F compression yield strengths were about 10 percent higher than the ultimate tensile strength. The compression yield strengths developed in this lot of material (Heat No. 55651) at room temperature and 600~F were about 6-10 percent higher than those indicated by the producer as "typical" (Ref. 5). This was a slightly higher deviation than was found in the case of the tensile properties of RH 950. WADC TR 59-339 8

Comparative data are tabulated below: Test Compression Treatment and Data Source* Temp (~F) Yield Strength (psi) RH 950 - "DESIGN" Room 232,00 600 181,000 Heat 55651 Room 245,000 600 199, 142 800 167,357 900 134,833 TH 1050 - "DESIGN" Room 194,000 600 160,000 800 130,000 900 98,000 Heat 55651 Room 220,667 600 185,500 800 146,800 900 113,877 *Notes: "DESIGN" - from design curves - Ref. 5, p. 96B Heat 55651 - average values determined at University of Michigan Tension-Impact Properties. The results of the tension-impact tests at room temperature and the elevated temperatures to establish base properties are summarized in Table 3 and plotted as a function of the test temperature in Figure 6. Some decrease in the tension-impact strength accompanied by slightly increased ductility occurred as the test temperature was increased. Fairly good agreement was obtained between duplicate tests at each temperature. In addition, the data for the RH 950 condition were considerably more consistent than the previous data for the TH 1050 condition (Ref. 3) which had a comparable level of strength. This is shown by the following tabulation. Tension-Impact Strength —ft-lb. RH 950 TH 1050 Test Temp. Range Average Range Average Room 38-46 43 33-70 49 6000F 38-46 42.6 31-57 40.1 800~F 26-41 32.7 24-33 29.9 900~F 27-29 28 34-50 43.8 WADC TR 59-339 9

Hardness. The hardness of the material as-heat treated was determined to be Rockwell "C" 48.2. This value is the average of five determinations made on each of six different specimens. The six specimens consisted of two each from three different sheets. The producer of the material indicated that a hardness range of 46-48 could be expected from this treatment. (Ref. 5). In contrast, the average hardness of the TH 1050 condition was determined to be Rockwell "C" 43.8, compared to the 42-43 indicated by the producer. ESTABLISHMENT OF EXPOSURE STRESSES Curves of stress versus time to reach creep deformations of 0.2, 0,5, 1.0 and 2.0 percent at 600~, 800~, or 900~F were determined to aid in the selection of stresses for creep-exposure tests. Six or seven tests were run at each temperature with the higher stress tests allowed to creep until fracture occurred. The test specimens removed from the creep units before fracture were tested in tension at room temperature in order to gain some idea of the effects to be expected from creep-exposure. The data from the creep tests and the tensile tests are summarized in Table 4. The curves of stress versus time for creep deformation are plotted in Figure 7. The slopes of these curves generally follow the slope of the rupture curve at the same temperature. Several inconsistencies in the data were observed in the 6000F tests and the curves drawn at this temperature are based on average values, The data obtained at 800~F and 900~F exhibited better consistency although a deviation was noted between duplicate tests at 800~F and 90,000 psi. The ultimate tensile strength was used as the 0. 1-hour rupture strength to aid in fixing the curves. Plastic deformation during loading occurred in all tests at 600~F and the majority of tests at 800~F. The nominal stresses for the required creep-exposures were determined from the intersection of the creep deformation curves with the ordinate at 10, 50 or 100 hours. In some cases, later experience with the creep exposure tests required readjustment of the stresses, Hardness increases of one or two points on the Rockwell "C" hardness scale were observed in most specimens after creep. The ductility after fracture increased moderately as the rupture time was increased. Tension tests of unfractured creep specimens revealed that increases in tensile and yield strength and decreases in ductility took place as a result of exposure to stress and temperature. Figure 8 is a plot of total plastic deformation versus room temperature tension properties for several specimens creep tested at 6000F for times between 331 and 437 hours. The plot shows that a severe drop in elongation occurred following creep. Increase s in tensile and yield strength of as WADC TR 59-339 10

much as 18 percent over the base value were noted. In addition, the yield strength was found to be equal to the ultimate strength for the three specimens tested after creep at 6000F. The fragmentary data also indicated that similar effects followed creep at 800~ and 900~F. TENSION AND COMPRESSION PROPERTIES AFTER EXPOSURE Unstressed Exposure Tension Properties. Tension tests at room temperature or the exposure temperature were conducted on samples of 17-7PH(RH 950) following exposure without stress for 10, 50, or 100 hours at temperatures of 600~, 800~, and 900~F. The test data are summarized in Table 5. The room temperature results (Fig. 9) show that no significant change in strength followed exposure at 6000F. Both the ultimate tensile strength and tensile yield strength were increased by exposure at 800~ or 900~F with the maximum effect possibly occurring after 100 hours at 800~F. For this condition the tensile and yield strengths were increased about 12-13 percent over the base value. Accompanying the increased strength was a decrease in ductility which was most marked for the 900~F exposures. The accompanying hardness changes (Fig. 9) were neither large nor appeared to be consistent. Tests at elevated temperature (Fig. 10) revealed 10-15 percent increases in the 800~F tensile and yield strengths after 100 hours exposure at 800~F —the condition also producing the maximum effect in the room temperature tests. The 600~F yield strengths were increased somewhat following exposure at 6000F, however, the 600~F ultimate tensile strengths were apparently not affected. The 900~F ultimate tensile strength and yield strengths were changed slightly and reached a possible maximum value at 50 hours exposure time and then decreased to slightly below the as-treated strength for the 100 hour exposure. Ductility tended to decrease with increased exposure time with the exception of the 600~F tests. Both the room temperature and elevated temperature tension properties of the RH 950 condition exhibited slightly different behavior than did specimens of the TH 1050 condition subjected to unstressed exposure under the same conditions. (Ref. 3). The maximum effects in room temperature tests of the TH 1050 condition were found for 50 hours exposure time at 900~F —an increased tensile strength of 15 percent and an increased yield strength of 18 percent. The 100 hour WADC TR 59-339 11

exposure at 800~F increased the tensile strength by 10 percent and the yield strength by about 14 percent —amounts similar to those obtained with the RH 950 condition, The hardness changes accompanying the exposures of the TH 1050 condition were somewhat larger than for the RH 950 tests, The ductility behavior was not significantly different, In the elevated temperature tests of TH 1050 following unstressed exposure, the 6000F tensile and yield strengths decreased moderately with increased exposure time, while the 800~ and 900~F strengths were either unchanged or increased slightly with increased exposure time. It appears, therefore, that the tension properties of the RH 950 condition were slightly more stable after unstressed exposure than those of the TH 1050 condition. Compression Properties. Compression tests at room temperature or the temperature of exposure were conducted on specimens of 17-7PH (RH 950) exposed without stress at 600~, 800~, or 900~F for 10, 50 or 100 hours, The results of these tests are presented in Table 6 and plotted in Figures 11 and 12, The suggested slight increase in yield strength at room temperature (Fig. 11) following exposure at 600~F was probably not significant since all the test values fell within the range for unexposed material. Larger and probably significant increases followed exposures at 800~ and 900~F. since all the values fell either just at or above the high side of the range established for the base conditions. The maximum increase in strength (for the 50 and 100 hours exposure at 800~ and 900~F) was about 9 to 10 percent above the value for the base condition. This was somewhat above the range of values obtained in tests of the as-treated material (Fig. 5) and is, therefore, probably a real effect. Check tests on a second specimen exposed for 50 hours at 800~F and one exposed 10 hours at 900~F showed excellent agreement with the first tests of these conditions, although there was a discrepancy between the two tests of specimens exposed 10 hours at 6000F. The elevated temperature test results (Fig. 12) generally exhibited increased strength with increased exposure time. Maximum increases, those for the 100 hours exposure at each temperature, ranged from 6-12 percent above the base value. The check tests run on several exposure conditions showed fair agreement. The comparison of the results with those for the TH 1050 condition revealed good consistency for the elevated temperature tests and some discrepancies in the room temperature results. In the room temperature tests, the TH 1050 condition showed little or no change in yield strength following the 800~ or 900~F exposures, while there was an apparent 20 percent loss in strength for either the 10 or 100 hour exposures at 6000F. However, a considerable amount of WADC TR 59-339 12

scatter made interpretation of these data difficult. For the elevated temperature tests of the two conditions, the general trends at each test temperature were the same while the absolute amount of the change was slightly less for the TH 1050 condition. Creep Exposure Room Temperature Tests. The results of tension and compression tests at room temperature following prior creep for 10, 50, or 100 hours are reported in Tables 7 and 8, and plotted as a function of the creep deformation for each exposure time and temperature in Figures 13, 14, and 15. The inclusion of both the tension and compression yield strengths in the same plot serves to emphasize the possible existence of Bauschinger effects. A summary of these data is presented in Figure 16, while the hardness data are included in Table 7, A correlation based on total plastic strain is presented in Figure 17. Figure 18 presents comparative data for the TH 1050 condition. Figure 13 shows that prior creep at 600~F had an effect on the room temperature tension and compression properties for all exposure times studied. The ultimate tensile strength and tensile yield strength were increased and the compression yield strength and elongation were decreased as the amount of prior creep increased, The increased tension yield strength and decreased compression yield strength indicate that a Bauschinger effect was operative in the material exposed at 600~F, (The Bauschinger effect will be discussed in greater detail on page 2 9 ). Examination of Figure 13 reveals that the amount of creep apparently had a slightly greater effect on the ultimate tensile and tensile yield strengths in the 50 and 100 hour exposures than it did in the 10 hour exposures. The compression yield strength was decreased most with creep in the 10 hour exposures and progressively less as the creep time was increased to 50 and 100 hours. The elongation decreased about the same extent regardless of the creep time. It should be recognized, as Table 7 shows, that short-time plastic strain was obtained during loading of most of the 6000F tests since the loads necessary to obtain the desired amounts of creep were generally above the proportional limit of the material. In most cases the short-time plastic strain ranged from about 10 to 20 percent of the total plastic strain of the test, while in only one case was it as much as 40 percent of the total plastic strain, A correlation of the 600~F data as a function of total plastic strain is presented in Figure 17. The curves had the same shape as the ones based on creep deformation and there was no difference in the indicated time dependency. The changes in strength were not excessive compared to the as-treated strength. The maximum increase in ultimate tensile strength was about 12 percent over the base value, while WADC TR 59-339 13

the tensile yield strength was increased about 19 percent at its highest. The maximum reduction in compression yield strength for 10 hours creep was 20 percent below the base value. The elongation, however, was significantly affected. From the original value of 8;2 percent the elongation was reduced to as little as 1 percent. The drop in elongation was rapid, reaching 1-2 percent for creep up to about 0.5 percent and then leveling off with greater amounts of creep. Hardness changes following creep-exposure at 6000F were limited to increases of only one to two points Rockwell "C". Prior creep at 800~F had a mixed effect on the room temperature tension or compression properties. (Figure 14). As the exposure time was increased, the properties were governed more by the exposure to temperature and were not as much a function of the amount of creep. Ten hours creep at 800~F resulted in behavior quite similar to that noted for all the 6000F exposures. The tension yield strength was increased and the compression yield strength was decreased with increased creep. Although the elongation was reduced somewhat by the exposure to temperature alone for 10 hours at 800~F, it showed a further tendency to decrease as the amount of creep was increased. The behavior following exposure to creep for 50 hours at 800~F was similar to that following the 10 hour exposures, however, the extent of the change was not as large as creep increased. This was particularly noticeable with respect to the ultimate tensile strength and the compressive yield strength. Exposure to creep for 100 hours at 800~F had only a slight effect on any of the properties except the tension yield strength. The ultimate strength was increased about 12 percent while the tension yield strength was increased about 15 percent by the exposure without stress. The addition of about 0.2 percent creep then caused the tension yield strength to increase about 7 percent over the astreated value. Meanwhile, the 8 percent increase in compression yield strength produced by the exposure to temperature alone was affected very little by creep of up to 2 percent. The loss in elongation was almost all due to the exposure to temperature. Hardness increases in the 800"F exposures ranged from 2 to 5 points Rockwell "C". In contrast to the 6000F tests, the creep-exposures at 800~F were conducted with short-time plastic loading strain being involved in only a very few instances. Creep-exposure at 900~F (Figure 15) produced small changes in the room temperature properties, however, the direction of the changes was not always the same as those produced by creep-exposure at the lower temperatures. The compression yield strength exhibited a tendency to decrease with increased creep for the 10 or WADC TR 59-339 14

100 hour exposures and possibly for the 50 hour exposures, while the tensile yield strength and ultimate tensile strength were apparently decreased with creep in the 10 or 50 hour exposures but not in the 100 hour exposure. The greatest change in strength from the 900~F exposures resulted from the exposure to temperature alone. Even then, however, the maximum increase, that of the tensile yield strength after 100 hours exposure, was only about 10 percent over the as-treated strength. The ultimate tensile strength and compression yield strength were increased to a lesser extent by the unstressed exposure. The creep exposures at 900~F either had no further influence on the strengths or caused them to be reduced to the level of the as-treated material. On the other hand, the exposure to temperature alone caused the elongation to drop to between one to two percent, while creep apparently resulted in no further decrease in the elongation. A comparison of these results with the data obtained for the TH 1050 condition subjected to similar creep-exposures revealed both similarities and differences in behavior. Figure 18 taken from Reference 3, summarizes the data for the TH 1050 condition. Although this plot correlates the data on the basis of total deformation, the general trends are valid for comparison with the plots of the RH 950 data based on creep deformation. The two conditions showed the greatest similarity in their response to 6000F creep. The ultimate tensile strength and tensile yield strength were increased with creep, while the compressive yield strength and tensile elongation were decreased. The TH 1050 condition did not show an apparent time dependency for the loss in compressive yield strength as did the RH 950 condition. The behavior of the ultimate strength and yield strengths of the two conditions after creep-exposure at 800~F was also fairly similar, however, loss in ductility of the TH 1050 condition was not as marked. Where the elongation of the RH 950 condition ranged from one to three percent, the elongation of the TH 1050 condition was reduced only to about four to five percent. The difference in behavior of the ductilities was also very evident following the 900"F creep-exposures. The severe loss in elongation for the RH 950 condition after unstressed exposure was not obtained in the TH 1050 condition; however, the RH 950 condition had a smaller tendency for changes in the ultimate strength and yield strengths after 900~F creep-exposure than did the TH 1050 condition. Elevated Temperature Tests. The results of the tension tests conducted at the exposure temperature following creep-exposure are summarized in Table 9 and the compression test data are summarized WADC TR 59-339 15

in Table 10, Plots of the test results are presented for each temperature and time in Figures 19, 20, and 21. Summary curves for the RH 950 condition are included in Figure 22 and similar curves for the TH 1050 condition are presented for comparison purposes in Figure 23, Tension and compression tests at 6000F following creep-exposure at 6000F (Figure 19) revealed effects very similar to those obtained from the room temperature tests following the same creep conditions, The ultimate strength and tensile yield strength were increased and the compression yield strength and elongation were decreased as the amount of creep was increased. The yield strength behavior in these tests was again consistent with the Bauschinger effect. The increase in ultimate strength following 3 to 4 percent creep was about 9 percent over the value for the unstressed exposure. This compares with a 12 percent increase in the ultimate strength at room temperature following similar creep-exposure. The maximum increase in the tension yield strength was about 18 percent (compared to 19 percent in the room temperature tests) while the maximum decrease in compression yield strength ranged from 20 to 25 percent (compared to 20 percent for the room temperature tests), The elongations were reduced to an almost identical extent following creep in both the room temperature tests and the 600~F tests, The similarity of the results of the room temperature and elevated temperature tests following creep-exposures at 6000F indicates that the subsequent properties were almost entirely governed by the amount of plastic strain, Research carried out in another phase of this investigation (Ref. 6) indicated that there is no apparent difference in the relative effect of short-time plastic strain and creep strain in cases where the short-time strain ranged up to 30 percent of the total plastic strain and where there was no opportunity for no-load recovery period during the test. These conditions were fulfilled by the present creep-exposure. In the tests conducted at 800~F following creep-exposure at 800~F (Figure 20) little or no change was observed in either the ultimate tensile strength or the tensile elongation. Depending on the exposure time there was a tendency for the tensile yield strength to be raised as the amount of creep was increased, The maximum extent of the increase was 13 percent in the 10 hour exposures which was reduced to about 5 percent for the 100 hour exposure. The compression yield strength appeared to undergo a transition in its behavior as the creep time was increased. In the 10 hour tests it was increased as the amount of creep increased, while in the 100 hour tests an initial increase due to the unstressed exposure was reduced as the creep increased. WADC TR 59-339 16

The tests conducted at 900~F following creep-exposure at 900~F showed a mixture of effects. (Figure 21). The ultimate strength was affected very little by the 10 or 100 hour creep exposures, while the apparent decrease in strength with increased creep in the 50 hour tests may not be a true effect. It is conceivable that the point for the 50 hour unstressed exposure was high due to experimental variability. This appears to be a possibility since the ultimate strength values obtained in the 900~F tests were all fairly close to the as-treated strength. Changes in elongation following creep-exposure at 900~F were generally small and confined to slight increases. The compressive yield strength decreased with increased creep for all three exposure times, while the tensile yield strength was changed only slightly by creep. The directions of the changes were not consistent. However, since the changes were small, the apparent inconsistency may be merely an effect due to experimental variability. A comparison of the elevated temperature data for the RH 950 condition (Figure 22) with the data for the TH 1050 condition (Figure 23) shows a greater similarity in the effects of creep-exposure than was the case in the room temperature tests. This similarity was particularly evident in the case of the 6000F data, and also in the behavior of the elongation data for all three test temperatures. Effect of Long-Time Creep Exposure An indication of the effect of creep-exposure on RH 950 material for periods longer than 100 hours was gained from the room temperature tensile tests on specimens used to establish the creep deformation properties of the RH 950 condition. These data were included with the creep deformation data in Table 4 and mentioned briefly on page 10. In Figure 24, the test points for the long-time creep test specimens are super-imposed on a plot of the relationships developed for the 100 hour creep-exposure at each of the test temperatures. The figures in parentheses are the creep time inhours. At 6000F the creep-exposure for periods between 331 hours and 637 hours caused some additional increase in the ultimate strength and tensile yield strength beyond the values established for 100 hours exposure, while the elongation did not appear to be significantly affected by the longer exposure time. Nevertheless, both the strength and ductility continued to be more a function of the amount of prior creep than of the time of exposure. At 800~F, exposures of 381 to 437 hours produced little or no further change in properties beyond those produced by the 100 hour exposures. The ultimate tensile strength and tensile yield strength WADC TR 59-339 17

were increased about 15 percent over the as-treated value, while the elongation was reduced to about one percent. The two points obtained from specimens crept at 900~F show that a longer exposure time caused a reduction in the strength and an increase in the ductility from the values established by the 100-hour exposure. In particular, the ultimate tensile strength and tensile yield strength of the sample exposed for 843 hours were very close to those for the as-treated condition while the sample crept for 336 hours showed a smaller decrease from the 100 hour value. The elongations of both specimens were increased to about 4 percent from the one to two percent of the 100 hour exposures. Nevertheless, these values were well below the 8.2 percent elongation of the as-treated condition. Apparently, an intermediate exposure time at 9000F had the greatest effect on the room temperature properties. These limited data for exposure periods beyond 100 hours did not materially affect the validity of conclusions to be drawn from the test data for shorter exposures. TENSION-IMPACT PROPERTIES AFTER EXPOSURE Tension-impact tests at room temperature or the exposure temperature were run on specimens exposed without stress for 10, 50, or 100 hours at 600~, 800~, and 900~F. Specimens exposed to creep for 10 or 100 hours at these temperatures were also tested at room temperature while the elevated temperature tests after creep-exposure were confined to specimens crept for 10 hours at 600~ or 900~F. Attempts were made to correlate the impact ductilities on the basis of both the elongation or the reduction of area. Unstressed Exposure Room-Temperature Tests. Data from the room temperature tension-impact tests following unstressed exposure are tabulated in Table 11 and plotted as a function of exposure time and temperature in Figure 25. In general, the unstressed exposure caused a decrease in the tension-impact strength. With the exception of the 100 hour exposure at 800~F which caused little change from the as-treated strength, the loss in strength became greater as both the exposure temperature and time were increased. A duplicate specimen which showed excellent agreement with the original data was run for 100 hours at 800~F. WADC TR 59-339 18

The ductility of these specimens also tended to decrease as the exposure time and temperature were increased. The elongation values appeared to be less severely affected than were the reduction of area values although the values were low and difficult to measure with accuracy. Considerably different behavior was noted for the TH 1050 condition subjected to similar unstressed exposures. (Ref. 3). The TH 1050 condition had a slightly increased tension-impact strength as the exposure time was increased at 600~ or 800~F. The exposure at 900~F for 10 hours caused substantial increase in strength which then dropped off somewhat for 50 hours exposure until for the 100 hour exposure it was only slightly above the as-treated value. The elongation of TH 1050 material was either unchanged or slightly increased by unstressed exposure. Elevated Temperature Tests. The results of the elevated temperature tension-impact tests of the RH 950 condition following unstressed exposure are summarized in Table 11 and plotted in Figure 26. A different effect was observed for each testing temperature. In the 600~F tests the strength was decreased as the exposure time was increased; in the 800~F tests there was a tendency for the strength to be increased; while in the 900~F tests the exposure apparently had no effect on the strength. The ductilitiy values in the 600~ and 800~F tests were not affected by the exposure, while the ductility of the specimens exposed and tested at 900~F was reduced slightly. This behavior was again different from the case of the TH 1050 condition. In the TH 1050 tests the 600~ and 800~ exposures showed little or no change in strength while in the 900~F tests there was a sharp rise in strength for the 10 hour exposure which then dropped off for the longer exposure times. The elongation values also were slightly increased. Creep Exposure Room Temperature. The results of room temperature tensionimpact tests following creep-exposure are summarized in Table 12 and plotted in Figure 27. Changes in the tension-impact strength produced by creep-exposure at 6000F were small and almost all within the range of strength of the as-treated material. The unstressed exposures at 600~F caused some decrease in strength which then appeared to be partially restored by the WADC TR 59-339 19

creep-exposure. The ductilities of these specimens decreased as the amount of creep was increased. The limited data did not indicate if the exposure-time was of any significance. The exposure time may have had some effect on the tensionimpact strength of specimens subjected to creep at 800~F. The specimens crept for 10 hours did not exhibit much change in strength from the decreased value obtained by the exposure to temperature alone for 10 hours, however, the two specimens crept for 100 hours showed a considerable reduction in strength from the value obtained by the 100 hour unstressed exposure. This reduction in strength appeared to be a function of the amount of prior creep. The ductilities of the samples exposed to creep at 800~F were all decreased from the as-treated value. Most of the loss in ductility apparently resulted from the exposure to temperature alone. The specimens exposed at 900~F were all subject to a loss of tension-impact strength and ductility that was due to the exposure to temperature alone. As far as could be determined, the addition of creep to these exposures did not at all contribute to the reduction in properties. The tension-impact strength was reduced about 50 percent, while the elongation and reduction of area were reduced to almost negligible amounts. The time of exposure also did not appear to be of any significance. Because of scatter in the test results for the TH 1050 condition (Ref. 3) it was difficult to reach conclusions comparing the effect of creep-exposure on the two treatments. The strengths of the TH 1050 condition after all temperatures of creep-exposure ranged from either no change to a decrease of almost 50 percent with no apparent temperature dependence. There was some indication that the tension-impact strength and ductility of the TH 1050 material declined as the amount of creep was increased, although the effects of exposure time could not be separated. No such loss of strength was obtained from the 600~F creepexposures of the RH 950 condition. There were some losses in strength from the 800 F creep-exposures, while in almost all of the specimens exposed at 900~F the tension-impact strengths were about one-half the as-treated value. None of the TH 1050 specimens exhibited the severe loss in ductility noted in the RH 950 specimens exposed at 8000 or 900~F, The majority of the TH 1050 specimens had reduction of area values of about 15 percent, while the lowest value found was 7.5 percent. In the RH 950 specimens exposed at 800~ and 900~F thereduction of area values ranged from zero to 5 percent. WADC TR 59-339 20

Elevated Temperature. A limited number of tension-impact tests were run at the temperature of exposure for specimens exposed to creep for 10 hours at either 6000 or 900~F. The data are summarized in Table 12 and plotted in Figure 28. Prior creep generally had only a slight effect on the elevated temperature tension-impact strength of the RH 950 condition. In the 600~F tests neither the strength nor the ductility was changed significantly from the values established by exposure to temperature alone. In the 900~F tests there was small indication of increased strength and decreased ductilityas the amount of creep was increased. The reduction of area data from the 900~F tests was subject to a considerable scatter, The test data for the RH 950 condition were slightly different from those obtained for the TH 1050 condition after comparable creep-exposures. In the TH 1050 tests, a slight decrease in the tension-impact strength with increased creep was obtained in the 6000F tests, while in the 900~F tests, an initial increase caused by exposure to temperature alone for 10 hours was lost rapidly as the amount of creep was increased. The elongation values for all the tests were low but were apparently more affected by the exposure to temperature alone than by the amount of creep. METALLOGRAPHIC EXAMINATION Optical and electron microscope techniques were used to study the microstructure of 17-7PH as-treated to the RH 950 condition and following creep exposure. In the as-treated condition the structure consisted of martensite, delta ferrite, various carbides, aluminum compounds and inclusions. Although the creep exposures and the exposures to temperature alone resulted in changes in mechanical properties and hardness, no gross microstructural effects correlating with the changes in properties were observed by the techniques employed. X-ray studies to be discussed later (page 23) suggested that a continuation of the precipitation of a compound tentatively identified as NiAl was associated with decreased room temperature ductility, however, no positive microstructural evidence was obtained to confirm this. Optical micrographs of 17-7PH are presented in Figures 29 to 34. The direction of observation specified on these figures are with respect to the axis of creep testing. This axis was transverse to the sheet rolling direction. As received from the producer, the material WADC TR 59-339 21

was in condition A (Figures29 and 30) —that is, solution annealed at 1925~F and air-cooled. The structure consisted of austenite and between 5 to 20 percent of delta ferrite appearing as stringers in the rolling direction. In addition, cubic particles of titanium carbo-nitride, Ti(C,N) were present. The production of the high strength RH 950 condition of the material was a three-step heat treatment consisting of heating at 1750~F, refrigeration at -100~F., and re-heating at 950~F. The purpose of the 1750~F treatment was to "condition" the material for transformation to martensite. A conditioning treatment at 1400~F results in martensite transformation at room temperature and is the basis for the TH 1050 treatment previously studied (Refs. I and 3). Conditioning at 1750~F for the RH 950 treatment produces a material that is stable at room temperature(i. e., the Ms temperature is well below room temperature) and is suitable for mild forming and straightening operations. Transformation to martensite is then obtained by refrigeration for 8 hours at -100~F. This can be carried out conveniently in an acetone-dry ice mixture. The higher conditioning temperature of the RH 950 treatment over that for the TH 1050 treatment also permitted retention of more carbon in solid solution in the austenite, which results in a stronger and harder martensite after- transformation. The final treatment at 950~F caused additional hardening believed to occur principally by precipitation of an aluminum-nickel compound. The structure of the material as-treated to the RH 950 condition is shown in Figures 31 and 32 at 1000X optical magnification. The only noticeable change from condition A is the martensitic structure of the matrix and the appearance of carbides at the delta ferrite boundaries. Figures 33 and 34 show the structure of a specimen crept to 0. 94 percent deformation in 100 hours at 8000F. The elongation of this specimen was 1.5 percent in a room temperature tension test. This was in contrast to the 8.2 percent elongation of the as-treated condition. No readily noticeable structural change from the as-treated condition was apparent. Due to the inconclusive results from the optical examination, recourse to electron microscope techniques was used in an attempt to resolve the structure. Although considerable effort was expended, the results were not entirely satisfactory due to the difficulties in finding a suitable etchant. Of the large number of etchants tried, only a modified nital, a 15% HCL, 5% HNO3, 80% alcohol mixture, appeared to bring out the structure without causing widespread pitting. Even so, the etching response was not entirely uniform from sample to sample and some doubt exists as to whether all phases of interest were delineated. WADC TR 59-339 22

Representative electron micrographs at 3500X of samples etched with modified nital are shown in Figs. 35 - 42. Also included are the elongations obtained in room temperature tensile tests of the specimens. A noticeable difference in structure exist between Condition A (Fig. 35) and the as-treated Condition RH 950. (Figure 36). In the RH 950 sample, carbide particles appear to have formed at the delta ferrite grain boundaries, the delta ferrite shows a roughening, and the matrix exhibits a transformation. The differences between the as-treated structure (Figure 36) and the specimens exposed to creep (Figures 37 - 42) are very slight if any. The roughness in the delta ferrite is less evident in the samples exhibiting low ductility after exposure, but otherwise neither the matrix nor the carbides appear to have been affected. A positive identification of the precipitating aluminumnickel phase could not be made from these studies. It could be speculated that the roughness in the ferrite is associated with the precipitation reaction, however, this is not at all conclusive. The decrease in the roughness in the crept samples may merely be due to the application of the stress and only coincidentally associated with the decrease in elongation. X-RAY STUDIES A limited X-ray diffraction study was made of two samples of 17-7PH(RH 950) in a further attempt to identify the structural changes, if any, resulting from exposure to creep. The specimens examined were an as-treated specimen and a specimen exhibiting a change in room temperature mechanical properties following 100 hours creep at 800~F. Optical micrographs of this specimen were presented in Figures 33 and 34. The mechanical properties d both specimens are summarized in Table 13, Specimen 6L-T6 exhibited an 11-12 percent increase in the ultimate tensile and yield strengths and an 80 percent decrease in elongation following 0.94 percent creep. Hardness increased almost 3 points in the Rockwell "C" scale. It should be recognized, however, that a major portion of the change in properties probably resulted from the exposure to temperature. This is evident from an examination of Figure 14. Three types of X-ray diffraction examinations were carried out on the specimens. A powder pattern was made from filings of the as-treated specimen, patterns were made from the solid samples themselves, and finally the minor phases were investigated with the aid of powder patterns from extraction residues. The data obtained from the diffraction films are summarized in Table 13, parts A, B, and C, WADC TR 59-339 23

Part A, Table 13, summarizes the measurements made from the Hull-Debye-Scherrer powder patterns of filings from the as-treated specimen. Exposure was for 6 hours in a 114.6 mm diameter camera utilizing vanadium-filtered chromium radiation. Only three diffraction lines were obtained and they were all identified as being produced by martensite having an average lattice parameter of 2.88A. The solid samples were subjected to diffraction in a Phragmentype camera. (Table 13, Part B). In this case, 10 hours exposure to unfiltered chromium radiation was used. A number of additional lines were obtained, however, the analyses of the films were complicated by the presence of beta reflections. Since the camera was uncalibrated, the martensite lines were used to index the films. As far as could be determined, the patterns from both specimens were identical. Apparently, therefore, no new phases were present in specimen 6L-T6. Due to the over-all weakness of the patterns it was not possible to determine if there was any significant change in intensity of any of the lines. An increase in intensity of certain lines wouldbegood evidence for continued precipitation of an existing phase during the creep exposure. In these patterns, the martensitic lines were readily accountable, however, the other weak lines could not be identified. Three of the lines —at "d" values of 2.07, 1.80 and 1.29 — fit the patterns for CrC and others fit the patterns for NiAl or Ni3A1, or even austenite, however, the evidence for the existence of any of these compounds from these patterns must be considered inconclusive. The factors making difficult the identification of the patterns from the solid samples were the following: 1. Several phases might be present for which only the stronger lines were recorded in the film. Since many carbide precipitates have their stronger lines at the same or very similar "d" value the differentiation between phases is rendered very difficult. 2, Additional lines that could be used to differentiate between carbides may be superimposed on matrix lines. 3. Due to the physical limitations of the diffraction camera, lines falling at "d" values of less than 1. 17 were not recorded. Thus, many conceivably useful lines were not available. 4. Finally, standard patterns may not even be available for some of the phases. WADC TR 59-339 24

Since the results of the examination of solid samples were inconclusive, a further study was carried out on the minor phases. These phases were obtained by either electrolytic or chemical extraction from the solid samples. This procedure has the advantage of concentrating the minor phases so thata greater amount is available for diffraction and also eliminating possible interference from matrix lines, The extractions were performed by using an electrolytic separation in 10 percent (volume) hydrochoric acid or a chemical separation in a warm 10 percent bromine-anhydrous methyl alcohol solution. The hydrochloric acid extraction was carried out for 2 hours at a current density of 1.5-2 amperes per square inch. The resulting solution and residues were centrifuged and washed with distilled water repeatedly until a clear centrifuged solution was obtained. The bromine extractions were carried out for 2 hours with care taken that the solutions did not become overheated. The separated particles and solutions were then centrifuged and washed in anhydrous methyl alcohol, In the case of the electrolytic hydrochloric acid extractions, a fine dispersion of particles was found adhering to the side of the centrifuge tube after the residue and solution had been centrifuged. This was scraped from the tube and subjected to X-ray analysis as were the major residues. The dried residues were placed in 0.03 mm diameter glass capillary tubes for diffraction analysis in a 114.6 -mm diameter Hull-Debye-Scherrer Camera. Vanadium filtered chromium radiation (40 KV, 10 Amps) was used for the 7-10 hour exposures. The diffraction patterns from the extraction residue are tabulated in Part C, Table 13. The patterns from the fine "adhered" particles from the hydrochloric acid extraction were identical to those obtained from the major residue. This was determined by visual comparison and consequently the films were not measured or reported in Table 13. The patterns for the hydrochloric acid and bromine extractions were fairly similar. The major difference between the patterns was the observation of the 2.03, 1.62, 1.44 and 1. 18 "d" value lines in the HC1 residues and not from the bromine residues. These represent a compound or compounds soluble in bromine but not in WADC TR 59-339 25

hydrochloric acid. There is further evidence from the intensity differences of the patterns from the HC1 extracts that a larger amount of this phase was present in specimen 6L-T6 than in the as-treated condition. No other consistent difference was observed between the patterns. Specific identification of the compounds present in these patterns is quite complex. In Table 13, Part C are listed the standard patterns of a number of compounds exhibiting fairly close correspondence to the lines present in the residues. A majority of the lines match the standard pattern for M23C6, however, it is very difficult to obtain accurate identification of carbides by the present technique when more than one is present. This can be readily seen by the similarity of "d" values for the several carbides listed. Furthermore, it is either known or suspected that substitution of various elements can occur in most of the carbides. For example, M23C6, where M = Cr, and/or Fe. This could appreciably alter the lattice parameter and structure factors so that the "d" values and intensities might be considerably changed from the standard patterns. The set of lines have "d" values of 2.03, 1.62, 1.44, and 1. 18 which were found not only to be increased in intensity in specimen 6L-T6 but also to be from a compound insoluble in HC1, show a fairly good fit to the pattern for NiAl. This could be taken as evidence of further precipitation of NiAl during creep exposure. Lines that fit the pattern for Ni3Al were also present, but the intensity evidence is not as suggestive as that for the NiAlI In addition, interference from other possible compounds is present for some of the stronger Ni3A1 lines. The evidence for other compounds is even less conclusive and consequently, all identification must be regarded as highly tentative. Several lines were found that show good agreement with the pattern for TiN. Although titanium is not an alloying constituent in 17-7PH steel, optical examination revealed the presence of Ti(C,N) —titanium carbonitride —in the structure. This is probably the source of the TiN lines. The stronger lines from the standard pattern for TiC did not fit any of the measured lines. A few additional lines were observed that did not fit any of the standard patterns that were consulted. The conclusions to be drawn from this limited X-ray study are the following: 1. The as-treated structure consists of martensite and several compounds. WADC TR 59-339 26 26

2. A tentative identification of M23C6 was made for one of the compounds. 3. Several other carbides are probably present —notably Cr Cr7C3. 4. Titanium nitride was tentatively identified. 5. A set of lines, tentatively identified as NiAl —and/or possibly Ni3Al —was found to show increased intensity after a creep exposure that produced increased strength and decreased ductility. 6. The compound showing this behavior was soluble in bromine but not in HC1. 7. No apparent change in the matrix or the carbides was observed as the result of creep-exposure. 8. Optical microscopy indicated the presence of delta ferrite and titanium carbonitride, but no specific confirmation of these phases was found by X-rays. Thus, it was fairly well established by these studies that the change in mechanical properties following creep-exposure of specimen 6L-T6 resulted from a continuationf an existing precipitation reaction rather than the appearance of a new phase. The precipitate concerned is probably NiAl. FACTORS GOVERNING PROPERTY CHANGES Examination of the data shows that the short-time mechanical properties of 17-7PH (RH 950) following creep-exposure were governed by two major factors: 1. An inherent structural instability. 2. The plastic deformation produced by creep. These factors acted either independently or concurrently depending on the temperature of exposure. In addition, the time of exposure had modifying effects on each one. In the 600 F exposures the amount of plastic strain governed subsequent properties; in the 900~F exposure it was the exposure to temperature that was important; while in the 800 F exposures there was an inter-mixture of the two major factors which was further influenced by the exposure time. WADC TR 59-339 27

From the standpoint of microstructure, in the RH 950 condition of this material the properties were developed by a multi-step heat treatment that had the following effects: 1. Caused the formation of carbides. 2. Caused the transformation of austenite to martensite, 3. Caused precipitation of an aluminum-nickel compound. Metallographic and X-ray studies indicated that there was apparently no change in the carbides as the result of creep exposure. There was a possibility that some strengthening could have taken place by additional austenite-to-martensite transformation during creep-exposure. This would imply that complete transformation had not been attained originally during the 8 hour refrigeration treatment at -100~F. This was possible inasmuch as heat treatment studies by the producer of the material had indicated that an increase in the refrigeration time to 24 hours produced slightly higher strength and lower ductility (Ref. 4). The metallographic studies in the present investigation failed to indicate any such change in the martensite matrix, There was evidence, however, that a continuation of the precipitation of the aluminum-nickel compound took place during creep-exposure. This reaction appears to have been stress-accelerated and occurred at a lower temperature or a shorter time than if the stress had been absent. An additional possibility is the occurrance of "strainaging" type reactions which so frequently occur in the temperature range of the exposures. However, verification of the presence or absence of strain-aging was not specifically investigated. Microscopic examination was also made to determine if microcracking could have been a factor in the creep-exposure. Samples were carefully examined in both the etched or unetched conditions after creep-exposure. No indications of internal microcracking were found. In addition, none of the electron microscope replicas exhibited any evidence of microcracks. Some evidence of intergranular surface corrosion was observed, however. In order to account for the possible contribution of strain-hardening an experiment was performed in which a specimen was plastically pre-strained 0. 5 percent in tension prior to a tension test at room temperature. The ultimate strength of this specimen was virtually unchanged from the base value while the ductility was reduced only from 8.2 percent to 7.5 percent. The tensile yield strength was increased about 14,000 psi. These changes in the ultimate strength and ductility were only a small fraction of the changes observed in these properties following the same amount of creep at 600~F. WADC TR 59-339 28

Therefore, it was possible to rule out strain hardening as a major factor, The change in the yield strength can be accounted for by the Bauschinger effect. The application of the concepts of stress-accelerated aging and the Bauschinger effect can be seen from Figure 43 which generally summarizes the results of the room temperature tests, In this plot, the short-time properties are related to the temperature of exposure for two conditions: exposure without stress for 100 hours, or creep to one percent strain in 100 hours. The data for the unstressed exposure provide a measure of the inherent structural instability of the material. The exposure at 6000F in the absence of stress had a slight effect on room temperature strength and ductility. An increase in the exposure temperature to 800~F caused an increase in the strength and a decrease in the ductility, while the 900~F exposure resulted in some drop in strength from the 800~F value and a continuation of low ductility. This behavior is typical of an aging reaction. The maximum aging effect occurred at 800~F while overaging caused the drop to 900~F. The application of one-percent creep strain caused large effects, (in addition to those produced by the exposure alone) following 6000F creep, some effects following 800~F creep and little or no effect following 900~F creep. For instance, the increase in the tension yield strength and the decrease in the compression yield strength following 600~F creep is behavior characteristic of the Bauschinger effect. The Bauschinger effect is caused by the residual stress associated with plastic deformation of a structure whose properties are orientation sensitive. For most materials the Bauschinger effect is at a maximum for plastic strains of between one and three percent. Since the Bauschinger effect has been observed both in single crystals and in polycrystalline materials, the usual explanation for the effect based on the differences in orientation between grains in a polycrystalline aggregate is not rigorous. A better approach is to consider the effect to be related to the differential orientation of residual stresses around slip bands. For instance, following removal of a given applied tensile load, some portions of the structure can be in residual compression. When the load is re-applied, this residual compressive stress first must be overcome before the entire structure is again in tension. Therefore, the net tensile load to cause a given WADC TR 59-339 29

amount of yielding is increased. Conversely, if portions of the structure are in residual compression following pre-strain in tension, then a smaller net compressive load must be applied in order to cause compressive yielding. The Bauschinge'r effect therefore causes an increase in the yield strength in the direction of pre-strain and a decrease in yield strength in the opposite direction, Whatever the ultimate cause, the Bauschinger effect follows plastic deformation, and therefore, the usual effects of plastic deformation on mechanical properties must be considered. However, the change in properties from 6000F creep-exposure is greater than can be accounted for by strain-hardening alone and thus other factors must have been present, The fact that a slight change in properties also accompanied unstressed exposure at 600~F indicates that the aging reaction was also present during the creep-exposure. Therefore, the changes in properties were due to a combination of stress-accelerated aging, a possible slight contribution due to strain-hardening, and to the Bauschinger effect. The aging reaction as it occurred in 100 hours at 600~ or 800~F is one that increased both the tension and compression yield strengths and the ultimate strength. Thus, if there was an inherent tendency for the compression yield strength to be increased by aging, the value of the compression yield strength observed after the application of tensile creep must be a net strength, reflecting the positive contribution of the aging reaction and the decrease caused by the Bauschinger effect. Similarly, the increased tension yield strength must include both the increase from the Bauschinger component plus the increase from the aging component. This explanation would account for the increased tension yield strength and the apparent lack of a decrease in the compression yield strength following the 800~F creep-exposure. The slight additional decrease in ductility could then be explained by the combined action of strain hardening and a stress-induced aging reaction. The exposure without stress for 100 hours at 900~F appears to be overaging since it caused a reduction in the ultimate tensile strength and tensile yield strength. At this point the compression yield strength may have been at its peak value since it could be possible that the yield strengths were affected at slightly different rates by the aging reaction. If this were true, then the decrease in the compression yield strength following creep at 900~F could then have been due to over-aging and not to a Bauschinger effect. The Bauschinger effect could be ruled out since if it had been operative there should have been an increase in the tension yield WADC TR 59-339 30

strength after 900~F creep exposure —in addition to the decrease in compression yield strength. Recovery effects tend to minimize the Bauschinger effect at 800~ or 900~F. The decrease in the elongation after 900~F exposure can be attributed to stress-induced overaging. Stress-accelerated aging also can be used to account for the effect of creep-exposure on the tension-impact properties. The reduction in tension-impact properties after 900~F creepexposure was governed by the exposure to temperature. At 800~F there was a loss in strength for a large amount of creep in 100 hours, while there was apparently little effect of creep in the 10 hour exposure. Again at 600"F, creep had some effect in reducing the ductility after the 100 hour exposure but not the 10 hour exposure. Thus, the addition of stress caused a deterioration in properties to take place at a lower temperature or perhaps shorter time than it would normally have occurred at in the absence of stress, Consideration also was given to the mechanism by which creep took place. It can be reasoned that the tensile and compression properties which in a short-time test depend on slip with grains should be most affected by creep that takes place by the same means. Similarly, properties that depend more on the strength of grain boundaries should be most affected by creep in the boundaries. Thus, damage to short-time properties produced purely by creep might be predictable if the mechanism of creep is known and if there are no extraneous microstructural effects. A study of the creep-rupture data suggests that the creep at 600~F took place principally by slip within the grains. This was indicated by the fact that the fracture ductilities of the specimens rupturing at 600~F (Figure 7) were not changed particularly from the elongation in the short-time tensile test at this temperature. In the 900~F ruptures, fairly ductile fractures were observed at the longer rupture times, while in the 800~F ruptures there appeared to be a transition in the relative fracture ductility at a stress level of 110,000 psi, A transition in the fracture ductility from brittle to ductile is often taken as an indication of a change in the mode of creep. Attempts to analyze the creep-exposure data on the basis of the concentration of plastic flow were rendered difficult by the necessity of accounting for the structural instability of the material, WADC TR 59-339 31

The bulk of the evidence indicates that the creep deformation affected properties principally by its influence on the aging reaction. That is, the stress was mainly a vehicle for producing the aging reaction that governed many of the properties. However, the stress was important by itself at 6000F and for 10 hours at 8000F in producing the Bauschinger effect. It cannot be emphasized too strongly that evidence to support these contentions is based on inference. There are indications that creep damage to short-time properties might take place by the suggested mechanism; however, in the absence of data free from the effects of microstructural instability, the matter must remain one for speculation. Research conducted on an "ideally simple, structurally stable" material would be of value in testing this hypothesis. So far the discussion has been based on the properties measured at room temperature after creep at an elevated temperature. An understanding of the results from the short-time tests conducted at the exposure temperature might also be gained by a simple extension of the preceding arguments. That is, the mechanism by which deformation occurs in the elevated temperature short-time test should be related to the mechamism by which creep took place at that temperature. If it is evident that both processes took place in the same way, then prior creep might have a significant effect on the properties. A review of the experimental results reveals that the strength at elevated temperatures generally had about the same dependency or lack of dependency on the amount of prior creep as did the room temperature strength. The major difference in properties was the drop in room temperature ductility following exposure at 800~ and 900~F that was not found in the corresponding elevated temperature tests. It appears fairly well established, therefore, that with the exception of the Bauschinger effect on yield strengths, prior creep affected the properties of 17-7PH (RH 950) by its influence on the aging reaction. COMPARISON OF RH 950 AND TH 1050 CONDITION In most respects the effect of creep-exposure on the short-time mechanical properties of the TH 1050 and RH 950 conditions of 17-7PH stainless steel was similar for the particular exposure conditions studied: creep of up to 2 percent in 100 hours in the temperature range from 600~ to 900~F. For both conditions there was a decrease in the ductility and the occurrence of a Bauschinger effect in the tests at room temperature or 600 F following creepWADC TR 59-339 32

exposure at 6000F, Again for both conditions, the properties following exposure at 800~ or 900~F were governed mainly by the exposure to temperature and not by the amount of creep. For neither condition was there a pronounced decrease in the tensile strength after any of the creep-exposures, Whatever change occurred in the tension-impact properties was also similar for both conditions. Despite these similarities in behavior, there were nevertheless two major differences between the TH 1050 condition and the RH 950 condition. One difference was the behavior of the ductility of the RH 950 condition in room temperature tension tests following 800~ or 900~F creep-exposure. In these tests the elongation was reduced to only about one to two percent, principally by the exposure to temperature alone, while the corresponding creepexposure of the TH 1050 condition did not cause a reduction in the elongation below about 5 percent. The other difference was the initially higher strength of the RH 950 condition which was also better maintained after creepexposure. Although the trends in strength behavior of both conditions were similar, the absolute strength level of the RH 950 condition remained from 30,000 to 60,000 psi higher than that of the TH 1050 condition. Where the streng:h of both conditions was changed as a function of the amount of creep, the relative change of the RH 950 condition was also less, Most other differences between the two conditions were minor and may have been due to experimental variability. The higher strength of the RH 950 condition was due to two factors associated with the initial heat treatment. First, the higher conditioning temperature permitted retention of more carbon in solid solution in the austenite, This resulted in a stronger and harder martensite after transformation. Secondly, the precipitation hardening treatment was conducted at 950~F instead of 1050~F. This could have affected the size or distribution of the precipitate or the degree of completion of the aging reaction, Continuation of the reaction during creep-exposure could have accounted for the decreased ductility of the RH 950 condition while the TH 1050 condition could have become overaged during the similar exposure. In applications where an initially high and well-maintained strength level is of importance, the RH 950 condition has obvious advantages over the TH 1050 condition. Where there is occasion to be concerned with the yield strength behavior the Bauschinger effects WADC TR 59-339 33

observed for both conditions must be considered. Where ductility is of importance, the less favorable behavior of the RH 950 condition must be taken into account, WADC TR 59-339 34

CONCLUSIONS The study of the influence of prior creep on short-time mechanical properties of 17-7PH stainless steel in the RH 950 condition shows that: 1. The ductility at room temperature and the exposure temperature decreased significantly following prior creep at 600~ and for short-times at 800~F. 2. The ductility was also reduced by exposure to temperature alone for exposures at 900~F and for longer times at 800~F. The amount of prior creep at these temperatures had little effect. 3. Short-time tests at 800~ and 900~F following creepexposures at these temperatures showed that there was little effect on ductility either from the temperature alone or the amount of creep. 4, The room temperature and 600~F tension yield strengths were increased and the room temperature and 600~F compression yield strengths were decreased by prior creep at 600~F. 5. The ultimate tensile strength and hardness were not significantly altered. 6. The tension-impact strength appeared to be decreased by creep-exposure although the effects were erratic. The effects of creep exposure observed on the RH 950 condition of 17-7PH were generally similar to the effects observed on the TH 1050 condition with the following exceptions: 1. The RH 950 condition was initially stronger and maintained its strength better after creep-exposure. 2. The RH 950 condition exhibited a greater loss in room temperature ductility following 800~ or 900~F exposure. The information available on the RH 950 condition indicates that the observed effects on short-time mechanical properties were mainly due to an aging reaction. This reaction took place at 800~ and 900~F under the influence of temperature alone. At 6000F the reaction was stress-activated. The data suggested that this occurred by additional WADC TR 59-339 35

precipitation of a nickel-aluminum compound although it should be recognized that strain aging reactions which so frequently occur in this temperature range could have been involved. In addition, the divergence between the tension and compression yield strengths following the 600~F creep exposures was due to the Bauschinger effect. The Bauschinger effect following the 800~ and 900 F exposure was minimized by the combination of aging and possible recovery effects. WADC TR 59-339 36

REFERENCES 1. Gluck, J. V., Voorhees, H. R., and Freeman, J. W., "Effect of Prior Creep on Mechanical Properties of Aircraft Structural Metals," WADC Technical Report 57-150, Part I, 2024-T86 Aluminum and 17-7PH Stainless, February, 1958. 2. Gluck, J. V., Voorhees, H. R., and Freeman, J. W., "Effect of Prior Creep on Mechanical Properties of Aircraft Structural Metals," WADC Technical Report 57-150, Part III, C11OM Titanium Alloy, May, 1958. 3. Gluck, J. V., Voorhees, H. R., and Freeman, J. W., "Effect of Prior Creep on Mechanical Properties of Aircraft Structural Metals," WADC Technical Report 57-150 Part II, 17-7PH (TH 1050 Condition), November, 1957. 4, Armco Steel Corporation Report,'Armco Precipitation Hardening Stainless Steels —Mechanical and Physical Properties of 17-7PH in Condition RH 950," February 6, 1956. 5. Marshall, M. W., Perry, D. C., and Harpster, N.R., "Enhanced Properties in 17-7 Stainless" Metal Progress, V. 70, No. 1, p. 94-98 (July 1956). 6. Gluck, J. V., and Freeman, J. W., "A Study of the Creep-Induced Bauschinger Effect in CIIOM Titanium" —to be published in 1959 as a WADC Report. WADC TR 59-339 37

TABLE 1 TENSILE DATA FOR 17-7PH ALLOY (RH 950 CONDITION) Ult. Tensile 0. 2% Offset Test Temp. Strength Yield Strength Elongation Reduction ot Modulus, E Hardness ('F) Spec. No. (psi) (psi) (%/2 inches) Area (%) (10 psi) R"C" Room 4D-T3 237,500 224,500 8.5 16.2 27.8 49.2 4S-T5 237,500 218,500 8.0 15.2 29.8 49.2 237,500 221,500 8.2 15.7 28.8 49.2 5A-T5 242,500 227,500 8.0 11.5 28.8 47.4 5G-T2 237,500 223,500 8.0 15.0 28. 0 47.0 240,000 225,500 8.0 12.8 28.4 47.2 6C-T6 235,400 221,400 8.0 15.3 28.4 47.2 6P-T6 235,500 219,500 9.0 17.0 29.3 49.4 235,950 220,450 8.5 16.2 28. 8 48.3 Average - 6 Tests 237,650 222,480 8.2 15.0 28.7 48.2 600 4S-T6 200,000 178,000 9.0 16.4 28. 1 4B-T4 205,000 174,000 8.5 12. 1 28. 0 202,500 176,000 8. 8 14.2 28.0 5G-T6 200,000 173,000 8.0 16.0 28.4 5Q-TI 198,000 167,000 6.5 12.5 28.0 199,000 170,000 7.2 14.2 28.2 6D-T2 19,000 170,000 5.5 14.2 28.4 6H-T2 192,000 169,000 9.3 14.0 29.2 195,500 169,500 7.4 14.1 28.8 Average - 6 Tests 199,000 171,830 7.8 14.2 28.4 800 4D-T6 171,000 157,000 10.0 29.4 27.4 4H-T4 163,000 140,000 13, 0 29.0 21.2 167,000 148,500 1. 5 29,2 24.3 5A-T2 171,200 151,000 17.3 28,4 25.5 5R-T6 162,000 142,000 13,3 27.5 29. 166,600 146,500 15.0 28.0 27.3 6P-T2 167,500 147,000 19.5 33.0 22.6 6L-T4 166,000 151,000 13.0 31.6 24.8 166,750 149,000 16.2 32,3 23.7 Average -6 Tests 166,783 148,000 14.4 29.8 25. 1 900 4D-TI 131,800 114,000 19.0 36.0 23.0 4E-T5 142,000 116,000 11.8 33.4 23.6 136,900 115,000 15.4 34.7 23.3 5C-TI 140,000 126,000 14.5 33.8 24.5 5M-TI 135,000 125,000 18.0 38.2 21. 8 137,500 125,500 16,2 36,0 23. 2 6C-T5 131,800 122,400 25.8 45.4 25.6 6S-TI 144,000 124,000 18.3 31.6 23.5 Average - 6 Testa 137,433 121,233 17.9 36.4 23.7 WADC TR 59-339 38

TABLE 2 COMPRESSION TEST DATA FOR AS-HEAT TREATED 17-7PH ALLOY (RH 950 CONDITION) 0, 2% Offset Compression Test Temp. Yield Strength Mod lus, E (F) Spec. No. (psi) (100 psi) Room 4B-T25 236,000 30.2 4K-T46 254,000 31.2 245,000 30.7 5J-T26 234,000 31.6 5E-3X 252,000 31.3 243,000 31.4 6J-X2 232,000 30.3 6E-X2 248,000 29.9 240,000 30. 1 8ST47 259,000 30. 0 Average - 7 tests 245,000 30. 6 600 4B-T27 222,000 29. 8 4K-T42 194,500 29.0 207,250 29. 4 5R-T27 200,000 28. 8 55J-T24 186,000 28.5 193,000 28. 6 6GX2 199,500 27.0 6AX2 201,000 28. 8 200,250 27. 9 8S-T41 191,000 27. 3 Average - 7 tests 199, 142 28.4 800 4K-T47 176,000 26.4 4B-T23 163,500 25. 6 169,250 26.0 5J-T23 167,000 26.6 5R-T23 175,000 26,6 171,000 26.6 6L-T51 170,000 25.8 6L-T54 152,000 -5.9 161,000 25.8 8S-T45 168,000 23.3 Average - 7 tests 167,357 25.7 900 4K-T44 138,000 23.8 4B-T21 120,000 22.6 129,000 23.2 5R-T22 141,000 23.4 5R-T25 137,000 23. 1 139,000 23.2 6L-T56 136,000 25.4 6L-T53 137,000 23.6 136,500 24.5 Average - 6 tests 134,833 23.6 WADC TR 59-339 39

TABLE 3 TENSION-IMPACT TEST DATA FOR 17-7PH (RH 950 CONDITION) Tension-Impact Test Temp. Strength Elongation Reduction of (~F) Spec. No. ft.-lb. (%) Area (%) Room 4E -T43 44 3 5 18.4 4H-T52 38 3.0 12.8 5Q-T33 44 3.0 12.4 6S-T33 46 3.0 12.0 Average 43 3.1 13.9 600 4P-T31 46 * 15.6 5L-3X 38 4.5 20.0 6S-T31 44 4.5 15.6 Average 42.6 4.5 17.0 800 4H-T11 26 2.5 19.4 5B-3X 35 3.5 18.0 5S-3X 41 * -- 6D-T12 29 3.0 20.0 Average 32.7 3.0 19. 1 900 4H-T13 27 19.9 5Q-T31 28 * 21.6 6J-3X 29 3.5 26.0 Average 28 (3.5) 22.5 * Speciman inadvertently bent following fracture. WADC TR 59-339 40

TABLE 4 RUPTURE AND CREEP DEFORMATION DATA FOR 17-7PH (RH 950 CONDITION) Subsequent Room Temperature Tensile Properties Ul Test Rupture Hardness Total Plastic Time to Reach Indicated Final Creep Total Plastic Ult. Tensile 0.2% Offset x\) Temp. Spec. Stress Time Elongation R.A. After Test Loading Def. Loading Def. Creep Deformation (hrs) Deformation Deformation Strength Yield Strength Elongation R.A. Modulus,E I (~F) No. (psi) (hrs) (% in 2 in.) (%) (R"C") (%) (%) 0.2 0.5 1.0 2.0 (%) (%) (%) (psi) (% in 2 in.) (%) (106psi) ( b600 4C4 183,000 310.7 12 22 50.4 0.95 0.30 0.1 0.8 8.2 41 > 7.95 -- -- -- ------ Uj 5A6 178,000 2228.8 11.5 -- -- 0.80 0.20 0.5 7.5 43 218 9.20 9.40 --... _ 6P4 175,000 1180.4 13 26 50.5 0.95 0.21 1 4 24 136 >> 3.4 -- -- 4S4 172,500 673 * _ -- 49.4 0.66 0.11 8 105 640 -- 1.02 1.13 267,000 267,000 3.0 9.8 30.7 4S2 170,000 437 * - -- 47,9 0.83 0.18 12 44 310 -- 1.12 1.30 263,000 263,000 1.5 11.0 29.0 5G1 160,000 331.1* -- -- 49.2 0.69 0.12 23 272 -- -- 0.53 0.65 256,000 256,000 2.5 12.1 30.3 6TT5 150,000 361 * -- -- 49.4 0.55 0.05 248 -- -0.1 0. 26 250,000 250,000 5.0 11.0 29.0 800 4D5 132,000 27.5 16 31 51.3 0.61 0.06.15.8 3.3 8.4 10.9 ** -- -- -- -- -- -- 4p- 6P6 125,000 74.1 19 33 51.9 0.47 0.04.8 3.5 11.5 28.5 >> 3.6 -- -- 4ET6 117,000 167.4 13 38 - 0.50 nil 1 8.5 45 97 4.9 ** 4.9 -- -- -- - 4D2 110,000 247.5 13 31 51.8 0.46 0.05 5.5 32 101 169 >> 2.4 - -- -- -- 6C4 100,000 437.1* -- -- 51.3 0.38 0.02 16 100 425 -- 2.11 2.13 265,000 260,000 <2.0 1.2 29.5 5A4 90,000 381.7* -- -- 51.9 0.36 nil 9 140 346 -- 1. 11 1. 11 >266,000 263,000 -- -- 29.2 6C1 90,000 1615 28.5 47 -- 0.36 nil 29 250 490 730 15.2 ** 15.2... __ __ 5JT3 80,000 575. 2* -- _ 51.0 0.31 nil 140 558 -- -- 0.52 0.52 -- 264,000 < 1.0 nil 30.3 900 5G3 72,000 48.6 34 43 5). 0 0.28 0.03 0.7 2.6 5.6 13.5(est.)>> 2.0 -- -- -- -- -- 4S3 70,000 70i6 46 51 50.0 0.28 nil Off scale-reference point lost. >> 1.7 -- -- - -- 6C2 60,000 194.9 40 54 50.2 0.22 nil 3 8 18 38 >> 3.3 -- --. _ _ 5G5 50,000 613.9 38 53 49.3 0.21 nil 7.5 25 62 134 > 9.5-... __ ~ _ 4D6 35,000 336.5* -- -- 49.8 0.14 nil 20 108 315 -- 1.04 1.04 247,000 243,000 4.0 7,3 28.2 5A3 20,000 843 * -- - 49.1 0. 10 nil 94 1100(est.) -- -- 0.43 0.43 236,000 232,000 4.0 16.0 29. 1 > Greater than. >> Much greater than. < Less than. * Stopped at. ** Estimate.

TABLE 5 EFFECT OF UNSTRESSED EXPOSURE ON TENSILE PROPERTIES OF 17-7PH (RH 950 CONDITION) Tensile Properties After Exposure Exposure Conditions Test Ult. Tensile U. Zo Offset Temp. Stress Time Temp Strength Yield Strength Elongation Reduction of Modulus E Hardness Spec. No. ('F) (psi) (hr) (~F) (psi) (psi) (% in 2 in.) Area (%) (10 psi) (R"C")* 4E-T2 600 none 10 room 241,000 226,000 7.0 14.5 30.0 48.9 6F-T5 600 none 50 room 242,000 224,000 7.5 16.5 29.8 5M-T6 600 none 100 room 238,000 226,000 7.0 10.4 28. 5 49.0 5R-TI 800 none 10 room 244,000 233,000 5.0 16.4 29.2 49.0 4H-T2 800 none 50 room 253,50Q 236,000 5.5 12. 1 28.3 49.0 7A-T5 800 none 100 room 267,000 250,500 3.5 4.7 29.5 51.0 8S-T 800 none 100 room 262,000 245,000 2.0 2. 5 31. 0 -- 264,500 247,750 2.8 3.6 30.2 51.0 6T-T6 900 none 10 room 258,000 242,000 2.8 6.7 31.5 47 9 7J-T44 900 none 10 room 256,000 244,000 1.0 1.0 28.7 -- 257,000 241,000 1.9 3.8 30.1 47.9 5T~T6 900 none 50 room 252,000 240,000 2.5 4.3 28.3 49.5 5J-T6 900 none 100 room 254,000 246,000 2,8 8. 5 29.4 46. 5 5C-T6 600 none 10 600 198, 000 183,000 6.0 15.7 25.2 49.4 4K-T6 600 none 50 600 202,500 171,000 6.5 16,6 27.2 50.0 6D-T6 600 none 100 600 203,000 184,500 7.0 14,2 29.5 45.0 4N-T5 800 none 10 800 174,000 157,000 11.5 23.6 22.9 51, 4 5T-TI 800 none 50 800 169,000 155,700 14.5 28.0 23.9 49.0 7Q-T4 800 none 50 800 178,200 164,200 10. 0 26.4 23.5 -- 173,600 159,950 12.2 27.2 23.7 49.0 5Q-T2 800 none 100 800 185,000 169,000 8.5 21.0 25 2 50. 8 4P-TI 900 none 10 900 142,000 130,400 18.5 36.8 20.5 51. 1 6H-T6 900 none 50 900 151,500 136,000 14,0 38,8 21,9 51.0 4K-TI 900 none 100 900 132,000 127,000 14.0 35.2 20.3 50.0 8K-T2 900 none 100 900 124,000 112,500 14.5 43.5 19. 0 -- 128,000 119,750 14.2 39.3 19.6 50.0 WADC TR 59-339 42

TABLE 6 EFFECT OF UNSTRESSED EXPOSURE ON COMPRESSION PROPERTIES OF 17-7PH (RH 950 CONDITION) Compression Properties After Exposure Exposure Conditions U. % O ffUset Compression Temp Stress Time Test Temp Yield Strength Modulus,E Spec. No. (~F) (psi) (hr) ('F) (psi) (106psi) 4K-T45 600 none 10 room 237,000 28.9 8S-T4 600 none 10 room 249,000 28. 8 243,000 28.8 5E3X2 600 none 50 room 244,000 29.7 6L-T52 600 none 100 room 248,000 30. 7 5R-T24 800 none 10 room 256,000 30.7 4K-43 800 none 50 room 262,000 29.8 8S-T46 800 none 50 room 260,500 30.8 261,250 30.3 4K-T41 800 none 100 room 261,000 30 2 4B-T22 900 none 10 room 263,000 30 3 4N-T33 900 none 10 room 264,000 29.4 263,500 30. 0 5J-T22 900 none 50 room 267,000 30.8 5J-T25 900 none 100 room 266,000 30.0 5R-T26 600 none 10 600 173,000 30.0 4N-T31 600 none 10 600 202,000 28.7 187,500 29.3 6MX2 600 none 50 600 201,000 28. 9 4B-T26 600 none 100 600 214,000 29.3 6L-T57 800 none 10 800 157,000 28, 3 5J-T21 800 none 50 800 180,000 27.8 6RX2 800 none 100 800 189,500 27.9 4N-T32 800 none 100 800 182,000 26.5 185,750 27.2 5R-T21 900 none 10 900 138,000 23.6 4B-T24 900 none 50 900 130,500 23.9 8S-T42 900 none 50 900 153,000 25.2 141.750 24.6 6L-T55 900 none 100 900 147,000 25.0 WADC TR 59-339 43

TABL~.. 7 EFFECTOF PRIOJRCR~P ~POSUR~ OH ROOMTEMPERATURJ~TENSILE PROPERTIES OF I?*?PH (Rit 950 COND/TIOH) F~lpp~t~tre Condltionl Room Tamperaufo Tendtim' Propertel Agter Expolur?' Nolninct[ Exl~aimre Co**~dtttona Actualoral;" Pl&attc Total To, aim-mr; Ten, lid 0. ~ (~f[iet - --' Reduction.... Temp. Time De~. Time Load D-~. ~f, Plastic' Der. Yield $rrenllth of Area ModuJt)m, E ~:-"~ ~l~at.ion hL~-L cr?~). _ (~,) ~pt} (p,,q.... Load Del. StrohBib' S c~:~hrl):= s(t;:i~* Del. __ 680. 10 0oZ 70-T5 t0. O 171.000 0.76 0.07 0.32 0.39 t. oa zsz, 000 z5~.000 z.o 6,9 31.z 49 5.5 6F-T7 18o0 t7b. 000 0.92 0.3t 0.44 0.75 1.36 ZZ9,000 229,000 i.5 5.9 28,0 *., i.0 8U-TZ 10.0 18~. 0OO 0,88 0.21 1.12 1.33 3.00 Z$ l,'000 251,000 2.5 t3.8 29,5 -- 2.0 7A-Tb 10,0 188. 0043 i. 0? 0.53 3,48 4.0L 4.55 268,520 26l,~00 t, 5 8.0 ~8,0 -- 0, 2 8M-T3 SO, 0 158,000 0, 63 0, 03 0. t7 0, 20 ~, 80 248,000 247,000 4, 0 t7.0 ~6. 6 *0.5?P-T4 50,0 t72,000 0.85 0,13 i.05 1,18 1.90 259,000 259,000 2,0 i2..0 26,4.* t.0 8K-TS SO, e 179:000 0,91 0. Z0 J,27 1.53 Z. 16 260,500 260,500 ZS i2.~ 31,5 -- 2.0 7tt-Tb 50,0 103. 000 1,0Z 0.30 3,46 3,76 $,46 272,000 265, ~00 1.0 5.7 ~i,6 -- 0.2 5R-T3 100,0 t52,000 0,60 0,.(~5 0. i? 0.23 0.77 247,000 239,000?.S 15.6 ~9. t 49 0.$ 4K-T2 100.0 179,000 ~ 0.$4 0.16 0,68 0,84 1.5Z 258,000 ~54~000 los 9,9 ~8. b 48 t.0 6L-TI t00.0 t77,000 0.90. 0,30 1o12 1,42 2,02 2blQ00 26t, 000 t,0 nit ~8.0 50 ~-o9,t P-T4 t00.0 liltt00 t.02 0.3~i 1.64 t,98 Z. 66 263,000 263,000 I.O 7.4 30.3 50 ~00. 0. Z 7J-TS 10,0 10Z,000 0.40 ni'l 0, t9 0.19 0.59 2524000 Zt0,500 2,5'to2 ~?, ~1.~ ~5 5M-T3 tO. 0 i 18,000 0.44 nit 0,52 0,5Z 0.96 258,000 256,000 2.3 4,7 Z9,4 ~J 1.0 70-TI 10.0 IZ6.000 0.53 0.05 1.30 1.35 i.63 ~60,000 260,000 1,0 3,5 29.1 5~ ~.0 8T-TS i0,0 13t.000 0.53 0.0S t. S8 1,63 Z, it 26t,000 26i,000 <5 3, I ~9,6 52 0.2 aM-T4 50.0 ~l,478 0,35 nil 0.21 0. Zt 0,56 257,500 248,000 3,5 6,5 29,5 -. 0_. 5 70-T6 50, 0 106, 00O 0, ~Z nil 0, 57 O. 67 0.99 263,800 2600000 l, S 2, 2 ~8, 3.-'.',0 8L-T6 50.0 i 18,000 0,$6 nil l. Z2 I. Z2 1,60 26~, 000 259,000 io5 ~,l 26,9 -- _2,0 7Q-T~- 50.0 tZ2,000 0.55 nil 4:45 4.45 5.00 26~, 000 26i, ~00 ~.5 5,6 28,,~.. ~ 0 0. Z SR -T5 t~0, 0 62,000 0, ~2 nil 0. ~ l 0. 21 0, 53 )250,000 -- 52 aT-T2 ~00.0 0Z,000 0.31 nil 0. Z4 0,24 0.55 260,000 261,000 2:0 2:8 2;.9 53 0. S 4P-T5 100,000 0.40 0.03 0,5t 0,54 0.91 >264. 000 -- - 2T. 8 50 100.~?C-T6 J00. t0l, t)00 0. 38 0, 0 i 0.55 0.56 0, 93 266,000 g63,000 n~l nit 30. ~ 53 1.0 6t.-T6 i.~0. ~ 0.43 art 0.94 0.94 1.37 267,000 246,000 i i5. 000 $.0 29.8 5, UU-T3 lil5 J00. tSo 000 0. 50 nil i. 2Z l, 22 i. 72 2660000 264. 000 n nil ~8.0 S2 Z,0 5C-T4 1~0.0 117,000 0.46 nil l, lb |. lb 1.62 262,000 Z60. Q00 1.0 1.7 27,2 tl 7q~-T$ (faUe~i)9l. 0 t18,000 0,52,4il....{at 0~ hr,)5, t......... e, 2 4~-T3 10.0 45,000 0, t6 nil 0.23 0. Z3 0*41 >248, 000 ~9 OT.~ ~o.o.,oo0.o.~8.~ o.~7 0.~? o,. 2.,ooo.;,:oo0 2:0,:0 2~,~ ~ to0 ~T-T5 10o0 66,000 0. Z6 nil 0,70 0.70 0.96 25t,000 ~42,000 i.0 2, l IZ, I ~J g.0 5~.T5 10,0 75/000 0,30 2.09 /.li 2,39 246,500 23t,000 5.0 7,6 28.1 4~ 0~t02?A-TI 10,0 76,000' 0.29 n $.2i 3,21 3,00 255,'000 229,000 nil rill 29,~ -. 50 8~.T~ 50.0' ~ 42,000 5.17 o 0,07 (~.58 0,65 0,75 242,000 236,000 ~..5 idl Z9,4 -. t.~ 5~'-~1 S0,1t $2,000 o. 21 ~tl l,$l 1.3t I.SZ 256,000 240,000 (,~t,) a.0 as 20.6., go 7C.TI f)Qg S9. ooo 0,24 nil'~50 3,50 3.74 237,000 228,000 nil nil 21~1.-..............,..........................,,........................................................................................,...,,,.,,.,,.. o,.., i I.~ t00 ~$-TS 100, g ILL, 000 0o07 nil 0, 15 0.16 0.23 2)0,020 230,000 t.S b, 6 28,4 -- 9.5 ST-T3 IQ~ }6, 0~0 0.15 nil 0.54 0,$4 0.69 25Z, 000 243,000 J,5 2. Z 3~,3 ~ t.e iT-T) ti~t)t {) 45,000 0.20 nit i.34 1,34 1.54 252,000 248,000 2,0 ~,S 29,~ 69 ].0?C-T~ 150,~ 52, o~ o. zt o. oz ~.34 ~.~6 2.55 ~54, o00 z.~4, o00 AS ~,5 31,6 ti ~ -':':-'/:=-*" "."'":~ —":'''- ~.~' ~ ~.....~,.,~'~ ~,,~ i.'','',~,,,',''~, "-',,,,'-',;"',,,'- ~, ~- ". _z-',::,'''~ _'..-:!;~:~,~"':~: 44 wADc TR 59-339

TABLE 8 EFFECT OF PRIOR CREEP EXPOSURE ON ROOM TEMPERATURE COMPRESSION PROPERTIES OF 17-7PH (RH 950 CONDITION) Actual Exposure Conditions Compression Properties After Expoure Nominal Exposure Conditions Total Plastic Total 0.2% Offsat Temp. Time Creep Def, Time Stress Load Def, Load Dot, Creep De(, Plastic Del, Total Der, To t Temp. Yield Strength Modulus,m ('F) (hrs) (%) Specimen No. (hra) (psi) (%) M 09( M M F) (psi) jo~p 600 t0 0. Z 6F-T6 10. 0 17, 000 0, 82 0, 15 0,43 0,58 [.Z5 room Z31,0000 48.3 0,5 5M-74 10.0 176, 000 0,0 0.15 0.53. 0.68 1. 33 room 206, 000 za. 8 1,0 4H-73 10. 0 18Z, 000 [. 38 0. 64 1. 56 2.Z0 2,94 room [93,000 28, 9 Z. 0 6H-T3 10.0 189% 000 1.27 0.61 Z. 59 3,20 3, 86 room 192, 000 26. 50 0. 2 6U-73 50.0 159,000 0.64 0.07 0, 31 0.38 0,95 room 238, 0 2. 0.5 7H-73 50.0 172,000 0.74 0.1 3 0.58 0,71 1. 32 room 211,000 48,6 1.0 8M-75 50.0 179,000 0.9?9. 0. 0.91 1. 17 1.83 room 202,000 27,86 2.0 7Q-T6 50.0 183,000 0.72. 0. 17 0.65 0.82 1. 37 room 205, 00 31. 0 75-T I 50.0 1830000 0.85 0,21 1. 61 [. 82 2.46 room 206,000 28. 000,02 4H-T6 100.0 153,000 0.56 nil 0. 16 0.16 6 0.72 room 215,000(?) 30.0 65=T2 100.0 154 000 0.68 nil 0, 34 1.02 room 235,000 30, L 0.5 5M-T5 100.0 169,000 0.79 0. 11 0.67 0,78 1,46, room 222; 000 306, 1.0 6T-T4 100.0 177,000 0.89 0. 14 1.47 1.61 2.36 room 208,000 3{, 9 2.0 5C-T3 100. { 181,000 1. 02 0.30 1.84 2. 14 Z.86 room 223,000 29.8 800 O. Z BU -74 10. 0 102,000 0.46 nil 0. 30 0. 30: 0. 76 room 257,000 31. 1 0. 5 7H-74 lO. O 118,000 0.47 nil 0.56 0.56 1. 03 room 249,000 30.1 1.0 8S-TZ 10.0 126,000 0.5. nil 1, 17 1. 17 1.69 room 243,900 29.2 Z.0 7P-Ti 10. 0 132,000 0.55 nil 1,36 1.36 1.91 room 242,~000 10...........................................................................................................................................!......... 50 0.2 5F-T3 50. 0 91,500 0.34 nil 0. 32 0.32 0. 68 room 272,000 29.8 0,5 7J-TL 50.0 106.000 0.44 nil 0.70 0,70 1,1 4 room 258,000 27,8 4U-T3 50.0 106,000 0.42 nil 0.64 0.64 1,06 room 264 000 30.4 1.0 7A-74 50.0 118.000 0.52 0.06 1.28 1.34 [,80 room 252,000 30, 7 2.0 8L-T3 50.0 12,000 0.55 0.08 3.68 3,76 4.13 room 254,000 29.7.................................................................................................................................................. 100 0.2 6T-T3 100,4 8.,000 0, 34 nil 0.23 0.23 0.57 room 263,000 31 9 O. 5 5C-72 100.0 100,000 0.37 nil 0.45 0. 45 0.82 room 247,000 30. 4 1.0 4K-T5 100,0 115,000 0.43 nil 1. 07 1.07 1.50 tool" 261,000 31. 6 2.0 5J-T5 100.0 117,000 0.49 0.08 1.70 1.78 Z. 19 room 258,000 30.0 900 10 0.2 5Q-Tb 10. I 45,000 0. 19 nil 0.27 0, 7 0.46 room 264,000 30, 5 0. 5 4P-'1'2 10. 0 58,000 0.?4 nil 0. 38 0. 38 0.62 room 459,000 32. 7 1.0 6H-T5 10. 0 67,000 0.27 nil 1,04 1,04 1.23 room?53,000 31, 6 2,0 6L-73 to. 0 75~000 0.32 0.07.19 2,21 2,51 room Z46,000 41, 3 50 0.5 4U-TZ 50.0 41,000 O. 15 sil 0.48 0,48 0,63 roonm 271,000 Z~. b 2.0 8 F-73 50,0 59,000 0.45 nil 3,39 3,39 3. 84 ruom11 259.000 3Z. { 100 0.2 5Q-T4 100.0 18. 000 0. 05 nil 0. 16 0.16 0.21 roo.~ 457,000 31.8 0.5 4N -T I 100.0 36,000 0, 14 nit 0. 44 0.44 0.58 roonm Z61,000 32.5 1,0 6F-'' 100.0 45,000 0. 18 nil I. 17 I. 17 1.35 roomn 26z,000 49. Z 2.0 5J-TI tuO.0 52.000 0. 19 nil 2.43 2. 43 2. 62 room 254,000 29.4 WADC TR 59-339 4

TABLE 9 EFFECT OF PRIOR CREEP EXPOSURES ON ELEVATED TEMPERATURE TENSILE PROPERTIES OF 17-7PH (RH 950 CONDITION) Actual Exposure Conditions Tensile Properties After Exposare Nominal Exposure Conditions Total Plastic Tstal Total Test Ult. Tensile 0.2% Offset Tem"p. Time Creep Del, Time Stress Load Del. Load Del. Creep Del. Plastic Del. Def. Temp. Strength Yield Strength Elongation R.A. Modulus.E Hardness ('F1 (hot) (M Spec. No. (hr~) (psi) )%)% ) ) (,) 0%) (%) (IF) (psi) (p%) S%) (lopti) Rockwell'IC H ^00 10 0.2 8U-T6 10.0 169,000 0.79 0.11 0.31 0.42 1.10 600 198.000 198.000 7.5 14.3 25. 5 49 0.5 6D-T5 10.0 176.000 0.80 0.05 0.74 0.79 1.54 600 Z16.000 216,000 2.0 7.0 25.6 50 17 1.0 8S-T5 10.1 182,000 1.11 0.39 0.99 1.38 2.10 600 213,000 213,000 1.5 7.6 25.6 50 2.0 7P-T5 10.0 187.000 1.18 0.45 2.18 2.63 3.36 600 217,000 214.000<est.) 1.7 8.3 25.5 50 (JO —.-..-. —- ~ -~ ----------------- ----------- ----------- -- - ------ _ —------ - ---------- - - - - --- ----------- -- - ---- - -------- --- ----------- - --------- ------------ ----------- ----------- 10C 0.2 6S-T4 100.0 153.000 0.61 niu 0.15 0.15 0.76 600 205.900 196.000 8.5 21.1 26.4 49 0.5 5M-T2 100.0 169.000 0.79 0.15 0.91 1.06 1.70 600 208.000 ~- 4.5 13.6 25.1 1.0 6F-TI 100.0 177.000 0.96 0.26 1.40 1.66 2.36 600 214,000 214,000 2.0 10.5 26.8 2.0 4B-T6 100.0 181.200 1.02 0.30 3.66 3.96 4.68 600 220,000 220,000 2.5 10.9 26.6 49 goo 10 0.2 8S-T3 10.0 100.000 0.36 nil 0.21 0.21 0.57 800 173,000 140.000(?) 13.0 29.8 25.0 0.5 7P-T3 10.0 118.000 0."52 0.03 0.61 0.64 1.13 800 172.500 172,500 14.5 33.3 24.4 1.0 8L-TI 10.0 126,000 0.53 0.06 1.03 1.09 1.56 800 181.800 179.900 11.0 26.1 24.1 2.0 8N1-T2 10.9 133,000 0.60? 1.07 1.07+ 1.67+ 800 177.700 176.300 12.0 30.2 24.3 7G-T2 10.0'133.000 0.66 0.04 1.91 1.95 2.57 800 180,000 176,200 12.0 25.5 24.4 SO 0.5 7C-T3 50.0 106,000 0.44 nil 0.58 0.58 1.02 800 176.000 176.000 12.0 24.8 24.3 1.0 4U-TI 50.0 118,000 0.49 nil 3.55 3.58 4.07 800 182.000 176,000 11.3 24.0 23,0 2.0 6U-T2 (failed)47. 1 121,300 0.47 0.09 ~ (at 45.5 hrs) 3.47 - —. ~- ~~ 100 0.2 4B-T3 100.0 82,000 0.33 nil 0.21 0.21 0.54 800 184.800 177.000 13.5 23.9 25.5 51 0.5 6F-T4 100.0 100,000 0.39 nil 0.38 0.38 0.77 800 18*,000 177.000 13.5 30.2 24.7 1.0 7B-T6 100.0 115,000 0.4Z nil 2.04 2.04 2.46 800 179.000 175,000 12.5 27.5 24.0 2.0 6D-T4 100.0 117,000 0.51 0.05 2.73 2.88 3.24 800 174.500 174.000 14.0 29.4 25.0 52 900 10 0., 6S-T6 10. 1 45,000 0.19 nil 0.32 0.32 0.51 900 137.200 125.700 13.5 35.5 23.7 47 0.9S 83-TI 10.0 58,000 0.25 nil 0.55 0.55 0.80 900 140.000 140.000 29.5 48.0 22.2 51 1.0 7P-T2 10.0 67,000 0.27 nil 1.05 1.05 1.32 900 136.000 132.000 16.3 40.0 22.6 51 2.0 4K-T3 10.1 75,000 0.28 nil 2.49 2.49 2.77 900 136.600 134,800 21.0 45.0- 20.4 51 SO 0.5 8K-T3 50.0 43,000 0.13 nil 0.73 0.73 0.86 900 124,000 115.000 17.0 45.4 20.8 1.0 7B-T3 50.0 52,000 0.21 nil 1.41 1.41 1.62 900 135,000 128,500 19.5 38.5 20.7 7R-T5 50.0 67,000 0,24 0.07 11.19 11.26 11.43 900 130.000 124,000 22.3 37.2 25.3 51 100 0.2 8M-T6 100.0 19.000 0.08 nil 0.17 0.17 0.25 900 134,000 124.000 31.5 44.0 22.3 0o5 7R-TI 100.0 36,000 0.12 nil 0.57 0.57 0,69 900 141.000 118.000 26.8 41.0 20.8 47 1.0 7G1-TI 100.0 45,000 0.23 nil 1.85 1.85 2.08 900 135.900 121,800 28.0 40.6 21.9 2.0 8T-TI 100.0 52,000 0.21 nil 2.88 2.88 3.09 900 140,000 131.000 21.3 55.5 23.9 SO

TABLE 10 EFFECT OF PRIOR CREEP EXPOSURE ON ELEVATED TEMPERATURE COMPRESSION PROPERTIES OF 17-7PH (RH 950 CONDITION) Compression Properties Actual Exposure Conditions After Exposure Nominal Exposure Conditions Total Plastic Total Total Test 0. 2% Offset Temp. Time Creep Def. Time Streas Load Del. Load Def. Creep Def. Plastic Def. Def. Temp. Yield Strength Modulus, E F) (ers) (9',) Spec. No. (lrs) (psi) (O ) ("lo) (is) () (%) (~F) (psi) (106 psi) 600 10 0.2 8L-T2 11.7 171,000 0.75 0.10 0.31 0.41 1.06 600 180,000 27.5 0.5 7R-T2 10.0 176,000 0.92 0.15 0.47 0.62 1.39 600 185,000 28.4 1.0 7G-T5 10.0 182,000 0.86 0.30 0.78 1.08 1.64 600 161,000 28.6 7B-T4 10.0 182,500 1.02 0.22 0.90 1.12 1.92 600 165,000 28.6 2.0 8K-TI 10.0 188,000 1.23 0.52 2.40 2.92 3.63 600 163,000 28.1 100 0.2 5T-T4 100.0 153,000 0.57 nil 0.11 0.11 0.68 600 187,000 30.4 0.5 8U-T5 100.0 168,000 0.71 nil 0.59 0.59 1.30 600 186,000 26.8 1.0 6T-TI 100.0 175,000 0.84 0.15 1.31 1.46 2.15 600 168,000 25.3 2.0 6F-T2 100.0 181,200 1.11 0.36 1.75 2.11 2.86 600 162,000 28.8 800 10 0.2 8K-T4 10.0 102,000 0.44 nil 0.27 0.27 0.71 800 168,000 24.2 0.5 711-TI 10.0 118,000 0.42 nil 0.55 0.55 0.97 800 175,800 25.9 5F-T2 9.9 112,000 0.49 nil 0.49 0.49 0.98 800 174,000 26.8 1.0 81.-T5 10.0 126,000 0.48 0.04 0.80 0.84 1.28 800 153,000 25.2 7C-T2 10.0 126,000 0.55 nil 0.93 0.93 1.48 800 166,800 27.4 2.0 6U-T6 10.0 133,000 0.65 0.09 2.90 2.99 3.55 800 174,000 25.7 50 0.5 7A-T2 50.0 106,000 0.43 0.02 0.62 0.64 1.05 800 189,000 26.2 1.0 8D-T2 50.0 119,000 0.47 0.03 2.13 2.16 2.60 800 161,000 26.9 100 0.2 4B-TI 100.0 82,000 0.30 nil 0.20 0.20 0.50 800 188,200 29. 1 0.5 8T-T6 100.3 100,000 0.38 nil 0.49 0.49 0.87.800 176,000 23.0 1.0 5C-T5 100.0 115S000 0.43 nil 1.27 1.27 1.70 800 166,000 23.9 2.0 7R-T4 100.3 117,000 0.50 nil 3.78 3.78 4.28 800 154,000 24.0 900 10 0.2 613-T3 10.6 45,000 0.19 0.0) 0.29 0.32 0.48 900 130,800 21.4 0.5.S-T6 10.0 8, 000 0. 21 0.0) 0.52 0,55 0.76 900 125,000 24.0 1.0 7Q-T1 10.0 07,000 0.65 0.01 1.25 1.26 1.50 900 121,000 23.8 2.0 4E-'1l 10.0 75,000 0.29 oil 2. 36 2.3 2.65 900 119,000 22.7 50 0.5 7D-..2 T 0.0 -15,000 0.16 oil 0.56 0.56 0.72 900 144,000 24.4 2.0 1)-TI 50.0 58,060 0.22 nil 3.03 3.03 3.25 900 1I31OOO 24.8 10 1,. O-l - IO.O 1,9, 00. 0.08 ill013 0,21 900 151,000 24.5 0.6 SM-I 100.0.36,600 0.12 nil 0.16 0.46 0.58 900 130,000 21.6 1.0 7J- I'6 101.0 -15,000 0.17 nil 1.46 1.46 1.63 900 142,000 23.,5 (US-TI 100.0 -14,000 0.2) il 1. 11 1.11 1.31 900 145,000 24.4 -,0 711-'1' 100.0 52, 600 0.24 0.02 2.31 2.35 2,57 900 126,900 22,2 WADC7TR 59-339 47

TABLE II EFFECT OF UNSTRESSED EXPOSURE ON TENSION-IMPACT PROPERTIES OF 17-7 PH (RH 950 CONDITION) Tension Impact Properties After Exposure Exposure Conditions Tension-Impact Temp. Time Test Temp. Strength Elongation R. A. (OF) (hrs) Specimen No. (OF) (ft-lbs.) (00) (00) 600 10 5H-3X room 37 2.5 20. 0 50 4P-T32 room 30 * 7.4 100 6D-TI room 33 3.0 nil 300 10 4B-T53 room 27 * nil 50 6D-T13 room 30 3.7 3.7 100 5R-T41 room 39 3.5 6.6 6S-T32 room 41 3.5 2.0 40 3.5 4.-3 900 10 6A-3X room 21 * nil 50 5R-T43 room 19 1.5 nil 100 4H-T12 room 26 0.8 nil 600 10 6K-3X 600 34 4.0 17.0 50 5K-3X 600 29 3.5 19.0 100 4H-T53 600 30 4.5 17.0 800 10 5P-3X 800 29 3.0 17.0 50 4H-T51 800 43 3.5 19.0 100 6E-3X 800 35 4.0 17.0 900 10 4E-T41 900 29 3.0 13.0 50 6Q-3X 900 27 3.5 14.0 100 5Q-T32 900 27 1.5 12.0 Specimen inadvertently bent following fracture. WADC TR 59-339 48

TABLE 12 EFFECT OF PRIOR CREEP EXPOSURE ON TENSION-IMPACT PROPERTIES OF 17-7PH (RH 950 CONDITION) t ______A_____t_____1_____E_____p__Actual Exposure Conditions Tension Impact Properties After Exposure () Nominal Exposure Conditions Total Plastic Total Tension-Impact Temp. Time Creep Det. Time Stress Load Def. Load Def. Creep Def. Plastic Def. Total Def. Test Temp. Strength Elongation Reduction of (~F) (hrs) (%) Specimen No. (hrs) (psi) (%) (%) (%) (%) (%) (%6) (ft-lbs) (%) Area (%) lid 600 10 0.2 8F-T2 10.0 170,500 0.64 0.14 0.32 0.56 0.96 room 40 1.5 14.0 0.5 7J-T3 10.0 176,000 0.86 0.20 0.50 0.70 1.36 room 45 2.3 12.7,,0 1.0 8L-T4 10.0 182,000 0.82 0.08 0.28 0.36 1. 10 room 38 1.5 16.0 t(J 2.0 7G-T4 10.0 188,000 1.15 0.40 2.38 2.78 3.53 room 38 0.8 2.2 100 0.2 5T-T2 100.0 153,000 0.59 0.06 0.19 Q.25 0.78 room 39 2.0 15.5 2.0 7C-T4 100.0 181,200 0.73 0.11 0.58 0.69 1.31 room 48 1.0 5.2 10 0.5 5F-T5 9.9 176,000 0.83 0.20 0.58 0.78 1.41 600 27 2.5 17.0 1.0 6U-T4 10.0 182,000 0.97 0.32 0.95 1.27 1.92 600 37 2.0 12.0 800 10 0.2 8F-TI 10.0 102,000 0.42 nil 0.26 0.26 0.68 room 47 1.5 9.0 0.5 7G-T3 10.0 118,000 0.54 nil 0.78 0.78 1.32 room 28 1.0 3.7 1.0 7P-T6 9.9 126,000 0.51 0.03 0.93 0.96. 44 room 35 1.0 3.7 2.0 8D-T3 10.0 133,000 0.60 0.08 1.86 1.94 2.46 room 26 0.5 3.0 100 0.2 6T-T2 100.0 82,000 0.34 nil 0.23 0.23 0.57 room 28 nil nil 2.0 4N-T2 100.0 117,000 0.49 0.10 2.00 2.10 2.49 room 11 1.0 nil 900 10 0.2 4N-T7 10.0 45,000 0. 18 nil 0.27 0.27 0.45 room 23 1.0 4.6 0.5 7R-T6 10.0 58,000 0.18 nil 0.61 0.61 0.79 room 18 0.5 nil 1.0 7A-T3 10.0 67,000 0.26 nil 0.97 0.97 1.23 room 18 0.5 nil 2.0 5J-T4 10.9 75,000 0.31 0.04 2. 85~(st.) 2.89(est.) 3. 16(est.) room 18 1.0 nil 100 0.2 8E-T1 100.0 18,000 0.09 nil 0.20 0.20 0.29 room 35 nil nil 2.0 8E-T2 100.0 52,000 0.21 nil 2.25 2.2s 2.46 room 16 nil nil 10 0.5 8F-T6 10.0 58,000 0.24 nil 0.94 0.94 1.18 900 27 2.5 nil 1.0 5F-T6 10. 0 66,000 0.28 0.02 1. 10 1.12 1.38 900 37 3.3 22. 0 2.0 4U-T6 10.0 75,000 0.32 0.03 2.28 2.31 2.70 900 43 1.0 6.0 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...,....

TABLE 13 X-RAY DIFFRACTION DATA FOR 17-PH (RH 950) BEFORE OR AFTER CREEP EXPOSURE AT 800~F Mechanical:Properties of Specimens Selected for Diffraction Studies Ult. Tensile Reduction Strength Yield Strength Elongation of Area Modulus,E Hardness Specimen No. Condition (psi) (psi) (%) (%) (10 psi) R"C" RH 950 As-Treated 237,650 222,480 8.2 15.0 28.7 48,2 6L-T6 800'F-115,000 psi (0.94% Creep) 267,000 246,000 1.5 3.0 29.8 51.0 X-Ray Diffraction Data A. Hull-Debye-Sherrer Powder Pattern (Filings) Measured'd" Values Standard Pattern for Martensite Specimen'd" Intensity "'d" Intensity (I) Indices RH 950 2.03 S 2.035 1 110 1.44 M 1.44 0.4 200 1. 17 MS 1. 175 0.8 211 B. Phragmen-Type Camera (Solid Samples) Measured "d" Values Standard Patterns of Possible Phases Martensite Unknown Specimen "d" Intensity "d" I RH 950 2.41 VW 1 6L-T6 2.27 VW ~~ (Patterns Identical) 2,.07 W ~ 2.03 VS 2.035 1 1.80 W / 1.44 M 1.44 0. 4 1.29 M _ 1,17 M 1.175 0. 8 C. Powder Patterns (Extracts) Type of Extraction Standard Patterns of Selected Possible Phases ** HCI (Electrolytic) Bromine Measured "di Values M23C6 NiAl Ni3AI Cr7C3 TiN CrC Al2Cr3 Unknown* "d"' I "d" I "d" I d"~'d" I ~I":F'~" iTr~mT ~-m S"~T "d'*~ >"d" ~1 ~ Specimen TRH 93 bL-T RH 950 5-TI - -~- -- -~- -T - ~~ z. 5z W! I ~ 1 ~' 2.53 MW 2.51 W'2'.45 VW Z.vw 45 VW. 2.44 VW 2.44 VW 2,43 VW 2.4 lM.t 3 W 2 _2.38 w 2. 38 w. "W 2.38 S 2.37 W 237 W 2.37 M z.17 W 2.17 MW 2.17W 2.17 W 2.17 S *2,28 M... ________ 2. 12 VW 2. 12 VW 2.12 W.2. 12 5 2. 2 Vs 2. lZ 0. 8 ____.___ 206 S 2.07 S 2.08 2.08 1.0 2.05 M ____ 2.05 S 2.05 S 2.04 S 2.04 S 2.0o5 0.1 2.03 VW 2,03 S 2.03 1.0 1.89 MW... 1,96 M 1...,9 1 O.92' 1.88 W' 1.88W 1.88 W 1.88 M.....1.86 S - 1.,87 0. 1 1.80 W 1.80 MW 1.80 W 1.80 W 1.79 S.. 1.79 S 1.78 W' 1.81.....1.77 VW 1.77 W 1.77 VW 1.77 VW 1.77 MW 1.76 M ______ 1.,62 VW ________ 1,68 W 1.,66 0,2 1.60 W 1.60 VW 1.60 VW 1.60'MW 1.60 W ___________ 1.50 VW 1,50 VW 1.50 VW 1.51 M 1. 50 S 1.51 0.8 _ 1.44 MW _________ 1.44 0.2 1.46 W 1.44 S 1,45.0,4 1.33 W 1.33 VW 1.33 VW 1,35 S.. 1.29 VW 1.29 VW 1.29 VW 1. 29 VW 1. 29 M _ 1. 28 VW ____.___ 1.28 VW...1,28 0.1 1.275.2 M i. 1.28 1.828 0.1"1.26 MS _________________ 1.26 S 1,26 M 1,25 0. 1._______ 123 M 1.23 W 1.23 W 1.23 S 1.22 S 1,22 M 1.24 0.1' 1.19 VW 1.19 W 1.19 VW 1,19 VW 1,23 1.0 1. 18 VW 1.18 S 1.18 Mi. 18 0.7 1.19 VW 1.18 S 1.19 0.8 1.17 VW 1. 17 VW 1.17 VW 1.17 VW 1.17 S..... 1,16 0.2 ** Other possible phases include: Ni.C, Al5Cr3, AI9Cr4Cr3C2, AI2Cr, Ti(CN)-(identlfied optically), Delta ferrite, etc. WADC TR 59-339 50

A { BT0(0jC{ Fi 0I IKILIM I11 N lP R{5{T U -~PANEL NO. 1;i i SHEETI 1 1 ^ 1 I ^ I Il ^1 ^1 SHEET2 111id iInIIIIIiis Sheet Designation: 1, 2, 3, -etc, Panel Designation: A, BP C, etc. Panel Location Code: IA, 3L, etc. (Sheet No. Panel No. Specimen Blank Sampin Sce: (SeeFgr for details) Sheets 1, 2, 3 All treated to TH 1050 Condition; Sampling Schemes W and Z as indicated, all others Scheme Y. Sheets 4, 5, -6:Part treated to TH 1050 Condition, balance to RH 950 Condition; Sampling Scheme Y used throughout.,,Sheets 7, 8:Treated to RH 950 Condition; Sampling Scheme Y used throughout, iii 111111 ~~~~~~11Is IY - Figure~~~ ~ 1. - Pae sapln Icem fo aheao 77Hsails te he WADC TR 59-339 51~~~~~i

XI I MI I TI,! M'2 1 T. C2 I I T2 X33 T3 13 X44 T4 x4 W66 C 26 6 M6 I~ T5 I' X5 T6...0 ^22 I T22 IX2 X33 T23 iX3 INCHES T - TENSILE (LENGTH ONLY) C - COMPRESSION ALL BLANKS, I INCH WIDE IM - TENSION-IMPACT X - EXTRA

Exposure Spec. 0. 530 (+ 003) Tensile Spec. 0. 500 0 -.15/1 Am — 4.8.... ~ 15/1 ~^ ~b- ~ Ppr ox... -'-D )2 1/4 ~ ~ Grind last 1/32 each edge, longitudinally \-5/32 D 3/8 D ___________________________~_________________________ 22 Tensile or Creep-.Exposure Specimen ____________________0.200_______________200 1 -1/4~ 3/4- ~ 2 ~ _3/4 1-1/4~> Tension-Impact Specimen DO NOT SCALE 0.500 ALL SPECIMENS ALL DIMENSIONS ININCHES (-(+ 0. 003) FULL SHEET THICKNESS ALL IDIMENSIONS N INICHES ______________________________'-. *'Q0. 064 INCHES L _____ _____ 2-3/4 ~ Compression Specimen Figre 3. - Details of Test Specimens (Tension-Impact and Compression Specimens Designed te be Cut from Creep Specimens after Exposure).

2 4 0 -. __. ___ ___ ___ ___ ___ ~ _ ___ ___ A1 ^^ Tensile 220 Strength 210 ___ 200 o 190 —- ~ - ~\_ ~_-~ ~ 18 ~Yield A Strength \ A ^ 170 ---- 8 ^ 160 ~~~ ~ ~ I~~~~~~~~~~ \\ A 150 ~ ~~~~ \ - H- A \ H 140 ~ —~~-A-U 0 130 ~-~-~ \ ~ 120 1 10 ~ ~-~~ ~~ ~~ ~ 0 100 200 300 400 500 600 700 800 900 30 o~ 2 0 ~- ~~_ -~ -~ ~ ~~~~ 0 ~ ) ^ S 0 ^~~~~~~~~~~~ Zo o0 0 0 0 100 200 300 400 500 600 700 800 900 Test Temperature -'F Figure 4. - Effect of Test Temperature on Tensile Properties of 17-7PH (RH 950 Condition) As Heat-Treated. WADC TR 59-339 54

Ss 6~~-6S HI D1 Ivi ~(uoTITpu'o 096 H4H) IHclJL-LT P01rO.l-sv JO qUU plOJ UOPSSOTXdtUOD UO OJn1p.TJ)(cuTOlI 1SOTL JO JJo I j j1,1A do- 0tnlp dm 9 IwpJj 006 008 00L 009 009 0017 00f 007 001 0 ~ _ 0 ~ ~ ~ - ~ ~ ~ ~ ~- ~ o2\001 ~ ~ - ~~ ~ -" ~ ~ 071 T _ _ 0171 ~ ~ \l ~ ~ ~ ~ ~ ~ ~ ~ ~~~ ~~ ~~~~091 C) o 0 091 OI081 ^ o~-~~ ~~~ 061 ^ \ 0 0 00 ~ ~ ~ -\ 0 ~ ~ ~ ~ "~-~ ~ ~~~~~~~~~~061 7 \0 0 \ ~ _ N ~ ~ ~ ~ ~ \^~ ~ ~ ~ ~ ~~~~~~~~~~~~~01?77 ~ ~ ~ ~ ~ ~ ~ ~ ~ ^~~~ 097

50 I 0I 0 j4 40 ~- ~1~_ -. 0 ____ 40 0 ^ 0 0 ^I 0)^^^0 ^ 30 -_~ 0 4-~ U Cd 20 S rI 10 0 *r4 (vn Z 30 cd 0 20 - 10 0 ~rq r4 0 U 010^ ~~ 0 100 200 300 400 500 600 700 800 900 Test Temperature - ^ Figure 6. - Effect of Test Temperature on Tension-Impact Properties of 17-7PH (RH 950 Condition) as Heat- Treated, WADC TR 59-339 56

230 ~~~~~ ~ 220 - Code I Rupture.....__1_ ___ _ Elongation on Rupture ~ 0, CreA^p 190 _ _ _- ( 0; C I ~~~~ -~~ ____ __ ^dup)licate test..190 ~~~ __ — — _ (12)'Note: Tensile strength used 180 G I ~ O_-~ 1'" e — as 0. I hr strength. 170 ~ ~ ~ ~~ ~ ~lF'i -- ~ Ar- 0 —-~]~a Rupture Time - hours I (14.4) 160 - -- {~ ~ 0 1 50 0. f... 140 (16) 90 __o,(13) __or,,____a 5o I o ^o ~ ~ ~ ~. ~\ ~\~'T Q..oo' ooo 80 —~~~ -- -~~~Time - hours At 0. I hr.9) 9 10 11 137400 psi 90.. 179% long... 7 ____ ____6o ____ ^ ^a 10 I0 ~N 4) _..., _. _.. — _ 60 ~~ - — 0 Li- Rupture- ~ ~ WAI 20 50 A- A-t6 — 900'F 0 Lo J 0....~I{~ ~ ~~100.... - 10~ 00 Time - hours Figure 7. - Stress-Rupture Time and Stress-Time for Creep Deformation Curves for 17-7P1-1 (RH 950 Condition) at 600', 800~, and 900~F. WADC TR 59-339 5

~>. 270. -_ - -~250 260 2 60..~ n 250' 240/ _-f As Treated oYS 0 Creep-Exposure 2 1 _ _( ) Plastic deformation obtained 0^ O during loading. 220 00^ 210 kO n d u ~0 Elongation 0 1.0 2.0 3.0 Total Plastic Deformation - percent Figure 8. - Effect of Creep Exposure at 600~F for 331-437 Hours on Room Temperature Tensile Properties of 17-7PH (RH 950).

o I 270 o 260 " 0 250 ~ ~ 24- _ _ _ 240 _ H-e 230 A 8001 ) Temperature *'F - ~ 900 ) L) / Unexposed, (average value for 7 tests) 220 250 ~~~ ~ 1 ~-, 240,... I/ I II L 2Q 230 -// r.220 0 210 10 1 1I I II 1 1 _~0 0' 60: 4 40 0 10 20 30 40 50 60 70 80 90 100 Exposure Time - hours Figure 9. ~ Effect of Unstressed Exposure at 600, 800*, or 900~F on Room Temperature Tensile Properties and Hardness of 17-7PH (RH 950 Condition). WADC TR 59-339 ^

210 4 180....... 170 - I - ~- _-~ ~ _ _ { 1~~ 0 160 -... 1501 140 i- ~~.. 130 ~~~~ 120 ____ 190 ~0 o 1,60 to 166 130 I C ode - I o 600* ) Exposure Temperature 13.' A 800 ) and 120 0 900 ) Test TJerperature - F Unexposed (average value for 6 tests) 30 X. _,, 110 iI~~1 0o 0 0 10 20 30 40 50 60 70 80 90 100 Exposure Time - hours Figure 10. - Effect of Unstressed Exposure at 600,'800', or 900~F on Tensile Properties of 17-7PH (RH 950 Condition) At Exposure Temperature. WADC TR 59-339 60

280.. - - 01 o- 270 250 I I 240 — ) C ode o _____ 600' ) Exposure A 800 ) Temperature - OF 230 H I i I U nexposed (average value for 7 tests) 0 10 20 30 40 50 60 70 80 90 100 110 120 Exposure Time -hours Figure 11. - Effect of Unstressed Exposure on Room Temperature Compression Yield Strength of 17-7PH (RH 950 Condition). WADC TR 59-3 39 61

220~ 0 180_ ___ A -~'_______ M ~ 160 o 150 14 U I 0 ]L Code 0 600 ) Exposure Temperature l ( ^tA 800 ) and 110 a 900' ) Test Temperature wF - / Unexposed (average value for 6-7 tests) 100_____________ 90 0 1O 20 30 40 50 60 70 80 90 100 110 Exposure Time - hEours Fig ure 12, - Effect of/ Unstressed Exposure at 600v,.800, or 900F on Compression Yield Strength of 17-PH (H 950 ) At Exposure. Temperature. WADC TR 59-339 62

10-hr Prior Creep at 600"F 50-hr Prior Creep at 600OF 100-hr Prior Creep at 600~F C) - _ 5_ ___ __ 270 -~_ Code 270 -.g_ —- - t __ -- 4 0 280.0 280 20..1Z70 270 270 H 0.!~o 1^5 _ __ ~ ~ ~ Z50 ~,t -~2 —~ 250 ~o-~- o ______ ---— ___I.' ~ /,0 E 0^0 0 40- - -.. 240 240 ~ 1 - 20 T Code 230~ 230 ~ —O-Tension Properties _________ a 230:'...... 3. —-Compression Yield 230 2~0 Unexposed 220. 220 ________ 0 1.0 2.0 3.0 0 1.0 2.0 3.0 0 1.0 2.0 3.0 27 2 j70 270 o 260 1o ^~,igr... 13. -.260 Tension- 260 Tension c 250 260P Tension of ______ (H 9i 26 O2x0 ToFensionr 0 A 250........... 240 ~~ 240......250. _-4 ~~ - \ — ~~ 2400 LOI0 \4 \ 210 2 0 A \ \-'' ~..... 1901,, 190 30 2-1.0 2.0 3.0 0 1.0 2.0 0 1 0 2.0 3._ r C) \ T ^ ~ /> Compression ~! I I Comp es~ion 0= I220 e -y E o ri orCreepat0 Compression00 190 ~ 1 ~ ~-19019Properties of 17-7PH (1R- 950 Condition). 0 1. 0 2.0 3.0 0 1. 0 2.0 3.0 0TQ ~ T 2, 0 3 O~ z 5 ~5 5 0 0 ~~ - ~0 1 1. 0 2.0 3.0 0 1. 0 2.0 3. 051 ~ 1.~ 0 Creep Deformation-5/ Creep Deformation-% Creep Deformation0/ Figure 13. - Effect of Prior Creep at 600'F on Room Temperature Tension and Compression Properties of 17-7PH (RH 950 Condition).

10 hr Prior Creep at 800~F 50 hr Prior Creep at 800"F 100 hr Prior Creep at 800*F 270 270 270 ~~m,.. 0 0 o260 o o —.-0 26026 0G~26 0 0260 H p4~250 250 250 "? I0 Code U1 I D 240 ~ 240/j ~ ~0~ Tension Properties 240,NO g, ~ 2 P — — A — Compression Yield 0 oJ2' Unexposed uo o 230 I 230. 230 E__ 220 I 220 ~~20__~1~2220 ________________________________ G) __ 2301' 220 1. 220 0 1.0 6 0 1.0 220 0 1.0 Z. 0.".34 5 6 0 10 2.0 2701- 270 270 I A Tension i 0 Tension 260 Tension -o- ~ 260 -- 2 60 m - O 0 F C4om-_re ~ mpresosionon -0 1240 0 240,/o/__ - 24- ~~~ 250 oCompression r O Compres sion 230 1 230 [ ~ 230 o IC 220_______ 2201 220o 210 - 210 ~~ J ~ 210 0 1.0 2.0 0 1.0 2. 3 4 5 6 0 1.0 2.0 ~e 10 10. - - 10. I I I I I C0 0 5 5~~ 5 s~ bo O o0 1"~_ 0_ 0 0 0 of o 0 1.0 2.0 0 1.0 2.0 3 4 56 0 1.0 2.0 Creep Deformation-% Creep Deformati6n-% Creep Deformation-%o Figure 14. - Effect of Prior Creep Exposure at 800~F on Room Temperature Tension and Compression Properties of 17-7PH (RH 950 Condition).

10 hr Prior Creep at 900~F 50 hr Prior Creep at 900~F 100 hr Prior Creep at 900~F 270 ~ 270 - 270 260 260- 2 60,~ o'=o 0 0 0 4 O- \0 0 250 0' 0 1.0 2.0 3.0 0 1.0 2.0 3.0 0 1.0 2.0 3.0._ _ _ ~ _ _ __ _ ____~ _ __ _260 1-^^ ~~~ 260 ~Compression______________________^___ 260 __ -._Compression 2 6J! 230 2O C' A^ ^ ^ Compression 1 -- - JI 2520 250 250 ~_ ^20 00 ^o 240 " Q ^__________________ 244_-A0 L __ __'_________________________ 0 Tension______ 240 ^ ^^^0 Tension 2400 0 240 Tension^^^^ 0 Tension ^Z3 0 230 ~-0 2 30 Code I - " ~0 — Tension Properties C 7 0mp-,ion ~ — a — Compression Yield 0 1.0 2.0 3.0 0 1.0 2.0 3.0 0 1.0 2.0 3.0 20 260 0 a, _ ~1 1 ompressionA~ _ ~~~~~~~~~~0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 00 ~ ~ ~ ~ ~ ~ ~~ ~ ~~~~~ ~o0f v40 0240 01 — 0 14 0 1.0 2.0 3.0 0 1.0 2.0 3.0 0 ~ T ~ 12.030 Creep Deformation-%o Creep Deformation- Creep Deformation-o Figure 15. - Effect of Prior Creep Exposure at 900~F on Room Temperature Tension and Compression Properties of 17-7PH (RH 950 Condition).

Prior Creep at 600~F Prior Creep at 800~F Prior Creep at 900~F M 280 1~0 280 ~ 101 hr 280 - 50 hrhr _270 | _ 270 1 270 01 o 2 __1 ___ Zo100 hr QN o260 260~~10 hr ~ 260,O'0 250 -Ten n 250 -/- I.r 250 CE3 _\ —4 150 hr h Tension,0. _0 l o -.. 240 240 240. Cd 1^50 hr 2 30 230 I 230. H 220_ _ I' 220 2 C o 220 -2 110 00a~ h~ r 50e270 270p 00 \hr U Tension 0 0 50 hr Fiur 16 U npoe260 d 260 C,por Compression oo f10 hr ( ~ 250 Tension \ IionI00 hrt I19 ______ ____________^^' 190. ___ _ 19^_~~~20 250- __ __ = 20....Cr Compression D100 hCreep'~ 54oP~ P:10 hrT o100 20 300.020130 100 30 4 Figure 16. - Summary of Effect of Prior CreeEhr Uxpos e d Tension 30 1 - 1of 0 Nore e... o,9 o ___ _______o__ _..,230 I23I 0 120 2.0 3.00. 2.0 3.0 0 1.0.0 3.0 4.0 0-~- 5 —----— Compresion 220 Code Creep DeformatPrion% Creep Deformation-% Creep Deformation-% F igu re 16. - Summary of Effect of Prior Creep-Exposure on Room Temperature Tension an Ud Compression Properties IO~of H 1 (RH 950). of 1.7-7PH (RH 950)..

Prior Creep at 600~F 280 50 and 1.00 ^ 7 hours _ O II 260 ~ 0|- ^U~A.- I 10 hours o 260'. ^^ 0 250______ Code ^ bp 250 / El> h^ /~ |^ Tension Compression Exp, Time o240X 0_ 10 hr o 0 o A A 50 hr 0rl 0 B 100 hr 230... XAvg. value for unstressed EH exposures. 220..~. 0 1.0 2.0 3.0 4.0 5.0 270... I | 1 50 and 100 hours 260 |. ~.4 hours 200'20 0 0 Ts ___ 4) ~A 25i 0 20 C hour 4 2, 4,TR 5,5 Figure 1 Room Temperature Tensile and Yield Strength 200osure erusTotl lasompression of 7P (Rh 950)Aoturs 0 WAD.C TR 59-339 67

Prior Creep at tLOOF Prior Cree o at 800.' Prior Creep at 900'F oGZ31240~~~~~~~~~~~~~~~~~~~ 1 p 8 1ol4__X-Lt40; 240 02i 1 i 2 C 0 ~.3 o 00,, I kr0 f ir Tio ~.! -1 9i i I I o 3 3 I Ii!o 2 I 1I /10 ~ C 210 ~ ~ ~ ~ ~ _0 __ 200 ~~20 2.o z/o r0 2 10 200 zo-2o 200 P - 0 170 ~ ~ ~ ~~ 170 ~ ~ ~ ~ ~ ~ ~ 170 0 1L0 2.0 3.0 4,0 5,0 0 1.0 2.0 3.0 0 1.0 2.0 3,0 4.0 18 - 8 - - - lll ii 2I'- - -240 - 90 -~ ~0 1 1 3 ~ 0 0.02 23.0 [ 0 1 30 20 220.. 220 - =1 I I I I I - Z,-0 2-10 210 l- 210 ~ ~~1~ 2t 00 ~20 0200 ~. 19 -190 ~~ - 190 Igo 18o. ~ ~ ~-~0 ~180.170 170 1 - 170 0. 7 ~ 1 /. 0 3. 0 ~-.0 -.0 0 i. 0 ~0 3.~0 0 -. 2.0 ~. 0 4~0 13011 13:::..T —, 0 ~ ~ ~ ~ ~ ~- 130 ~0 I 10 j 0 1.0 2,0 3.0.00. 3. 0 1.0 2,3.0 4.0 Tntll Dlors,,tis - pertent its l)lo' toli t is rctilt Total Defloranationl - percent Figure 18. - Summary of Effect ol prior Crfti, Exposure at 600', sUo*, or 900'F os Houn Teiiiper.ttilr Piriria of 17-7PH (FrH 1050 Coonition). WADC TR 59-339 68

10 hr Prior Creep at 600~1 100 hr prior Creep at 6006F 1 230 ~ i 230 220 / 22 o O 200 f- 2/0 0 ~ 1 Code s I - O~-0- Tension Properties 190 ------ Compression Properties 190 190 / Unexposed (ZI I 1 180 - 180,,o 0 1.0 2.0 0 1.0 2.0 3.0 4.0 220...... 2201~~1~. J',,-0 — 0 210 1/01 Tens0ion0 Cree DefoTemnstion Fige 1, -/ E t \ aTension a_ o 210 - 0 - ~~~0~~~~~~~~~ ~ 1?0 Compression 170 omression 160 -A- 160 150 ~7I. 150 0 1.0 2.0 0 1.0 2.0 3, 0 4.0 20 j 20 0 & 10 10 ~- ~~ O 0 ^ 0 o0 - 0 0 1.0 2.0 0 1.0 2.0 3, 0 4,0 Creep,Deformation-%o Creep Deformation-% Figure 19. - Effect of Prior Creep Exposure at 600~F on Tension and Compression Properties of 17-7PH (RH 950 Condition) at 6000F. WADC TR 59-339 69

10 hr Prior Creep at 800~F 50 hr Prior Creep at 800~F 100 hr Prior Creep at 800~F a> ^ 200, 200 10 _... 2001~ 0o ~CeI,0 ( \ r — g ~ Tension Properties O'~~., 16 0| -I --- A — Compression Properties 160 ~O O 1,0 2.0 3.0 160 / Unexposed 16 0 " 150 ~~ 150 150 0 1.0 2.0 3.0 01.0 2.0 3.0 4.0 0 1.0 2.0 3.0 4.0 0o 1.0, O 2. 0 31.0 2.0 3.0 2200~ o 200 oo~~ 0i ~-~190 ~- ~ 4- - --— _-~ 190 ~ _a 19~ -~_ _.....-........-..........1..... i I ~.\ 180 Tension ~ 180 Tensrion 180e\ TensionF e Aio o of'.- -- o- Iondiio-0 o. 170 1 70/, - / I 4 /'^~ ",CompressionP e ^ 17 0 —-- Krpeso I- Compression ~ 1 oO I//- _____ 160____ompeso 1o........60.... -~__ 130 ~ 130 130...0 0 i.0 2.0 3. 0 0 1.0 2.0 3.0 4.0 120 _ _ _ _ I: 0__ 201 17 o'I7 t I 00 -C ion 0 14 0... 0 0 1.0 2.0 3.0 0 1.0 2.0 3.0 4.0 0 1.0 2.0 3.0 4.0 Creep Deformation-% Creep Deformation-% Creep Deformation-%o Figure 20. - Effect of Prior Creep Exposure at 800~F on Tension and Compression Properties of 17-7PH (RH 950 Condition) at 800~F.

10 hr Prior Creep at 900~F 50 hr Prior Creep at 9O00F 100 hr Prior Creep at 9~00F a~x. n3, 170 170 1 ^ r~ ~0 ~ 170 00 S _______________ ___.___ ___________ _______ Code 160 160 --- Tension Properties 160 ~ — i-~ —~ — Compression Properties ~~~~~150~~~~~~~~~~~~ /L Unexposed 150 150 I 150 ~^~~~~~~~~~~~~~~~~ I JJ.-___^ I^-~ ____ 1_0 ___ _o_ o _ _ ____ ()10 ~0 I~' 30 12 30 1 3 I o 121~10 I Ton 0 Tensio 1o ir0 ___ ___ ___-__ 1__ ___ 0___ ___ __ ___ 4 I~ 140 C 1 ________ ________ 10 I 130 Q1 30j 130 0 o _ _ o. i~~o 2.0.3.0 ^^ ~ T^ ~ ^ ~!T^ ^"~"T~~~~~o0 30 10 Crep TensDeformation Tension-% Figure 21. Effect of Prior Creep-Exposre at 900F on Tension and Compression Properties of 17-7PH (RH 950 Condition) at90F. 100 30 0 30 30 I 0 20o 0 i, 1.'o.0 3.0 0 1.0 2o.0 3.0 o 1. 0 0 1. o

Prior Creep at 600~F Prior Creep at 800F Prior Creep at 9006F > ~~~~2301~~~ 20 ~~~~ ~ ^170\ ~~ 0 rI200 2. Zo -o 160 Q - Ts - b - 190 ~~~ ~~ o) 10 hrs 9 H~~~~~~~~~~~~~~~~~~ -- ^zio t 18010 hrs i^ - ______ —~_____00 has 50 hr F - 150 - - _________ _________F______rs ^ 1~~~~210~,^ ~~ 180 ^ g^~^ ^ ~"" ~ 150^ ~~ -z.o100 hrs Qn/'^^ "^ 100 hrs ^ En 200/ ~~ 170J ~ 140 -- - 100 hrs I I / \I ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~10 hrs ^ 190 160 130 ~ 180 ~ 150 ~~ 1120 ~~ ~ 0 1.0 2.0 3.0 4.0 0 1.0 2.0 3.0 4.0 0 1.0 2.0 3.0 4.0 ~o 2201 ~~~ ^ - ~ 2001 ~~~~ 160^ ~~~~ 110 hrs ^ -~ "" ] 00hr-s 210 1~/ ^'~ 90 ~~~150'-~. Compression ~ ~~ -^ \ / y^Tension Tension sin^ T ~> 200 ^\-^~ ~~~ 180 0~ lOOhrs ~ 140 ~0 hrs ^ ^~-V V ~ Compressi0n ~ ~ ~- 1hrs ~ 190 -' ________ 10lir 10oo%.......l~r 170 \ 130 50 hrs ( 180 160 V204I,0 h"...s.. 160 ~\-^ 4 ~~10 ~~ 15/~~ 190 _!. -— Compression 5 hr 10 1\ Compr40 0 100 hesion 10 Ie 0 4s 50 ~ ~ ~. h{ l~~~~~~~~hrs ~ ~ ~ ~ ~ ~ lO'r ______________________________- [ PirCep ________________________ _______________ __________ ________________ _________________________________ 1610 ~ - - 140 100 150 _____ -— 130 90_________ ~~-_~i_~~ zol" ix____ _____0 r o]~ 100hrs i""~~_~~~~~Tm I0 hr s~ Note: Heavy lines are,: 0 I,U -rs 10 - compression data - 10 __________2.0_____ - [~~~~~~~~~~~~~~~~~~~~~~~~~5, ~~,,fr...' Unexposed TensionP o -'NN. ~ Unexposed Compression_____1 100 ~ ~ ~ ~ ~ ~ ~~' - hrsl Q\ ~ \ ~ 1 ~ 1 ~ 1 o ~1~ 180 0 1.0 3,0 0 1. 0 2. 0 3. 0 4.0 0 1. 0 Z. 0 3. 0 4. 0 0 1. 0 2. 0 3. 0 4. Creep Deformation-% Creep Deformation-% Creep Deformation-% Figure 22. - Summary of Effect of Prior Creep Exposure on Elevated Temperature Tension and Compression Properties of 17-7PH (RH 950).

Prior Creep at 600~F Tested at 600*F 200,O 200 =.! Prior Creep at 800~F ~~~~~~~~~~~~~o I I I I I ITested at 800~F g 190 ~ ~ ~ ~ ~ ~ ~ 180 -'tc^~~~ 180 W _ ~~~ > w F W F:F F WPrior Creep at 900'F M ^ **L n*Tested at 900 F a 180 1 70 - 0 I t'" i t" 170 ) 160 10 oI o-,r c ~ oI o 160 " = 0 t t I J' 20 a 1 I 1 I | | I h, 30 i..... 3 100 1 0 110' 0 -0 -- [ 100 I O 1. 0'-,0 3. 3. ( O 1. 0 1. 0 2. U 3. 0 190'1 ~1~ 1 160 140 ~~~~ ~ 180 ~ ~ 150 IT - I - - ~ ~ - 1 30 ~ 1 0 1.0 2.. 3.0 190 j~1~1~1~1~,~,~j 170 1 1.0 20 300 ~ 10 o 180 1 11~~ ~ -10 130. i -, o o.!. \.l 140 140 100 ~ 130 -—,1 ^-~ ~ ~ ~ ~ g 140~1~^^^^~ ~ ~ S 190~~ ~ ~ 190, 180 ~ 170 t o' V ~ 5 \\ 0 1g. 132Una0 0 i ne 160 1o O 0\ o 12 0 1 1450 0 1 1300 010 203 0 130 - 0 l O 0 ~,[ ~ — ~. o,.o 2 0 a.0 I5~{ oo I I I' o WA0 T -- 39 73 I;I i[ [ ] I I _ I 1 k o 1.0 0 3.0 01.0 2.0 3. 0 1.0 2.0 3.0 1't)ttl c)lorw.1tion Ort cni TotlI Dlurlorttio)n - rr 0). 1 To eioctal i)elormation - percent

Prior Creep at 600~F Prior Creep at 8006F Prior Creep at 900F 270 (7)270. 270 (673) O/ 27 0 ) 1100 hr - - 0(4-37) o 260 260 60 0 / 260 _100 hr (37) 260hr 73 ^ 250 -0 ~~ 250 250 ~ 50 (336),0 ut 240... 240 ~ 240p I. 4 0 o (843) tO 1 230 230 230 220 220 220 Ln 0 1.0 2.0 0 1. 0 2.0 0 1.0 2.0 270 f 270 270 (673) 0%437) (575) 381) 260 (331)-^~ 260'0- 260 0 100 hr (437) 0 / /100hr - -. I ol o (336) h. 240 240 240 0 (843.1 t 230 230 230 04 ZZ 220.. 2200 210 2 210 - Code - 210 210. F~Y} Base condition un — o — Exposure time in 200 200 parentheses 200 100 hr prior creep 190 190 190 (361) _ (843) (336) a 5[ ~(673) ~ ~ 5 5 0 \'o 5 O - -) 5 5 t 0 (331)0?(437) 5 ) 1 0 2. 10 2.0 0 1.0 2.0 Creep Deformation-% Creep Deformation-% Creep Deformation-% Figure 24. - Effect of Long Creep Exposure on Room Temperature Tensile Properties of 17-7PH (RH 950 Condition) — Compared with Effects of 100 hr CreepExposure.

800~F <' 40 kt-0 g I I0 00~F m30 i _ 900 i OF I 20 E,20 -— t CODE 0 600oF 25 o 80-F Exposure 0 O eo TnoI a pempe o 3g 6 0 60F 0 0 39 E 3 8 0 500 o 5. U EfcoUsrx osu e 10 \ 900o 6o",7009Fo ~ ~~ ~ o 0o 0 10 20 30 40 50'60 70 80 90 100 Exposure Time-hours Figure 2-5. - Effect of Unstressed Exposure on Room. Temperature Tension-Impact Properties of 17-7PH (RH 950). WADC TR 59-339 75

E.. I I I........... o 0 100 _ I I I o o in —- -; 0 0 1 30 Ex 5 0o900 I I ICode i0Expose TmF Ex-posure Temperature Figure 2 800-F and - erat900F Test Temp-erature 0WADC TR 59-339 76 A [~'.^^^ ~i. - Z~ ~ ~ 600-F o.. I ~8o( 0 —--- 0 -_1 O' O w 0 10 20 30 40 50 60 70 80 90 100 Exposure Time-hours Figure 26, - Effect of Unstressed Exposure on Elevated Temperature Tension-Impact Properties of 17-7PH (RH 950), WADC TR 59-339 76

Prior Creep at 6008F Prior Creep at 8006F Prior Creep at 9006F!::: 1l 50 ~ ~1 50 501~~. 0 I.. 100 hr 0 (u I \ o H 4 ^-40 lh 0hr 44 o 0o 0 U ^3 30 30 3 0 10 hr 1 u h c Qd Code 0O * 0010 2hr 1 w 200 - 10~ hr 2 Exposhre 20 20------ 100 hro Time ) 101~\-~' Unex osedj ~0 )0 0 100 _ _ 10 0 0 ~~6 0 0 1.0 2.0 3.0 0 1.0 2.0 3.0 0 1.0. 0 3.0 I 200 20 20 10 105,~ 5~1 10 0 3 0 0 0 Oa2 00 1.0 23 04 1.0 2.0 30'o J I 0 I oIo=^ I n^ -O j~~, o w 0 1.0 2.0 3.0 0 1.0 2.0 3.0 0 1,0 2.0 3.0 Creep Deformation-7o Creep Deformation-o% Creep Deformation-) Figure 27. Effect of Prior Creep Exposure at 600. 800", 9000F on Room Temperature Tension-Impact Properties of 17-7PH (RH 950).

10 hr Prior Creep at 6000F 10 hr Prior Creep at 9000F 150, 1 50 ~ 1140~ 4j 0 I I 00 ~30 ^408.,40 ~~ <~ o f 0 4 30 I30 fh4l Bi O L 20 U 020 0 Unexposed 0 1.0 0 0 20 020' C0 i 0 1. 0 2 0 2.0 3.0 01. 10~~~ 1____________ - 0 I.~ 05. o 0 1.0 2,0 0 1.0 2.0 3.0 Creep Deformation-%o Creep-Deformation-% Figure 28, - Effect of Prior Creep Exposure at 6000F or 9000F on Elevated Temperature Tension-Impact Properties of 17-7PH (RH 950). WADC TR 59-339 78

:>l-2 ~.: ~tt2~2~~~~~~~~~~~^NL:: <C>: ---- tz~ ^ ~ure 29 (Longitudinal Face) xlOOO Figure 30 (Transverse Pace) xlOOO 17-7PH Stainless Steel: Condition A A-1~~~~~~~~~~~~~~~~~ ar42^^^"cx ^.. ^^..' ^1 ^^ ^:....... rure 31 (Longitudinal Face) xlOOO Figure 32 (Transverse Face) xlOOO 17-7PH Stainless Steel: Condition RH 950 211 247 2~ 2 >> 2 S; 2~-> >. 2.2'^ ~ f 2. > <\'%'.M>22~~4 >2> 24^ 4 33 L gu n Fc 0Fg 2 4.(Transverse F. -4> "- ^ (." -~.,..^ ^ "- -.fi'^ L...^ ~~^;"~..l A ~ ~~~.. ^:.^.... ~~~'~ ~ ^ " ^.',-2~2 > 2->22> > r5 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~ - ~-..^ -~; -~~ ^ -~ - ~ ^ - ^ —-^-^~~2 >2 ^ure 33 (Longitudinal Face) xlOOO Figure 34 (Transverse Face) xlOOO 17-.7PH Stainless Steel: Condition RH 950___________, Specimen No:'.. 6LT6 Creep~ Teste LOG"' hor >t800 o 4 Dfrmto -ures "9' 4 -^.^ Optca Mirgah of 17-7PH Stainles Stee (Al samples^......^f.^ -.. ~1"'^-..etched.. wit Marbles-..:.,l Reagent)..-~ ~- "-. -"^s "" M:l'-' W A D TR 59U:.. - ^ - 339.^..79~~;^;:.~:>... ~ ~~-.~".. ~:.' ^. i ^~.".

Figure 35 x3500 Figure 36 x3500 Condition RH 950 Condition A As Treated R.T. Elong. 20-30% R.T. Elong. 8.2% Figure 37 x3500 Figure 38 x3500 Condition RH 950 Condition RH 950 600~F-100 hr-No Stress 600~F-100 hr-1. 12% Def. R.T. Elong. 7.0% R.T. Elong. 1.5% Note: Specimens subjected to indicated creep-exposure; RT Elong., is elongation in subsequent room temperature tensile test. Figures 35-38. - Electron Micrographs of 17-7PH Stainless Steel (Samples etched in modified Nital). WADC TR 59-339 80

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270 ~ ~~~~ - ~~ 1% Creep in 100 hrs En 260 ~ ^^~~~~~~ ~ ~ ~~~~~., ~_ _J/ l go 250 ~I ____ie ___ H /100 hr Unstressed } exposure 240 /_ _~~~ o0~ 0.... M ^ I ~~I 230 8~ I_ %..........:_ _I H 50 ~ ~ ~ - - ~~Ohr \ ~ ~ ~ S~~~~~~~~~~~~~ ~ 240 -- ra / 0 230 ~' __ ~~_ o ~ -.~ ~ ___ ___ ____ I,3O J- O100 hr Unstressed exposure 210:~i J I I I [ 270 ---—. 0 100 hr Unstressed/ { exposure __ 2 1 60 ~- -.. BS -- 250 ~~~L -/ ~~ -__ 0 _ "~_ _______ _ _____ ____ -— 6__ ___ 240 - /1% Creep "' [^~ ~ ~ ~- /in 100 hrs 230 ~ -4~ ~-~.. - ~ 210 - — _.. o2 210I~ ~~ 10j~ ~~~~~ o''~ - 100 hr Unstressed ____ ex I_ _ j posure _____ b - -- lo Creep j _Q 0 j in 0l0 hrs I _ N 00 100 200 300 400 500 600 700 800 900 Exposure Temperature-~F Figure 43. - Effect of 100 hour Exposure Either Unstressed or to One-Percent Creep on Room Temperature Tension or Compression Properties of 17-7PH (RH 950 Condition). WADC TR 59-339 82

UNCLASSIFIED UNCLASSIFIED University of Michigan University of Michigan Research Institute Research Institute Ann Arbor, Michigan Ann Arbor, Michigan EFFECT OF PRIOR CREEP ON EFFECT OF PRIOR CREEP ON SHORT-TIME MECHANICAL SHORT-TIME MECHANICAL PROPERTIES OF 17-7PH STAIN- PROPERTIES OF 17-7PH STAINLESS STEEL (RH 950 Condition LESS STEEL (RH 950 Condition Compared to TH 1050 Condition), Compared to TH 1050 Condition), by J. V. Gluck and J.W. Freeman, by J. V. Gluck and J.W. Freeman, March 1959, 82p. inci, illus, March 1959, 82p. incl., illus, tables, 6 refs, (Proj. 7360; Task tables, 6 refs, (Proj. 7360; Task 73604). WADC TR 59-339). 73604), WADC TR 59-339), (Contract AF33(6161-3368), (Contract AF33(616)-3368), Unclassified Report UNCLASSIFIED Unclassified Report UNCLASSIFIED (over) (over) UNCLASSIFIED UNCLASSIFIED University of Michigan University of Michigan Research Institute Research Institute Ann Arbor, Michigan Ann Arbor, Michigan EFFECT OF PRIOR CREEP ON EFFECT OF PRIOR CREEP ON SHORT-TIME MECHANICAL SHORT-TIME MECHANICAL PROPERTIES OF 17-7PH STAIN- PROPERTIES OF 17-7PH STAINLESS STEEL (RH 950 Condition LESS STEEL (RH 950 Condition Compared to TH 1050 Condition), Compared to TH 1050 Condition), by J. V. Gluck and J.W. Freeman, by J.V.Gluck and JW. Freeman, March 1959. 82p. incl., illus,. March 1959, 82p, incl., illus, tables, 6 refs, (Proj. 7360; Task tables, 6 refs, (Proj. 7360; Task 73604). WADC TR 59-339). 73604), WADC TR 59-339), (Contract AF33(616)-3368), (Contract AF33(616)-3368). Unclassified Report UNCLASSIFIED Unclassified Report UNCLASSIFIED (over) (over)

The effect of creep to 2 percent in UNCLASSIFIED The effect of creep to Z percent in UNCLASSIFIED 100 hours at temperatures from 100 hours at temperatures from 6000 to 900~F was determined on 600~ to 900~F was determined on the tension, compression, and the tension, compression, and tension-impact properties of 17-7 tension-impact properties of 17-7 PH (RH 950 Cond. ) at room temper- PH (RH 950 Cond. ) at room temperature or the exposure temperature. ature or the exposure temperature. A substantial loss in ductility was A substantial loss in ductility was observed in room temperature ten- observed in room temperature tension tests. Material exposed to sion tests. Material exposed to creep at 6000F exhibited a substan- creep at 6000F exhibited a substantial Bauschinger effect in tension tial Bauschinger effect in tension and compression tests. The loss in and compression tests. The lossin ductility is attributed to stress and/ ductility is attributed to stress and/ or temperature induced aging dur- UNCLASSIFIED or temperature induced aging dur- UNCLASSIFIED ing the creep-exposure. ing the creep-exposure. The effect of creep to 2 percent in UNCLASSIFIED The effect of creep to 2 percent in UNCLASSIFIED 100 hours at temperatures from 100 hours at temperatures from 6000 to 900~F was determined on 6000 to 900~F was determined on the tension, compression, and the tension, compression, and tension-impact properties of 17-7 tension-impact properties of 17-7 PH(RH950 Cond.) at room temper- PH(RH 950 Cond. ) at room temperature or the exposure temperature. ature or the exposure temperature. A substantial loss in ductility was A substantial loss in ductility was observed in room temperature ten- observed in room temperature tension tests. Material exposed to sion tests. Material exposed to creep at 600~F exhibited a substan- creep at 600~F exhibited a substantial Bauschinger effect in tension tial Bauschinger effect in tension and compression tests. The loss in and compression tests. The loss in ductility is attributed to stress and/ ductility is attributed to stress and/ or temperature induced aging dur- UNCLASSIFIED or temperature induced aging dur- UNCLASSIFIED ing the creep-exposure. ing the creep-exposure.

UNCLASSIFIED UNCLASSIFIED University of Michigan University of Michigan Research Institute Research Institute Ann Arbor, Michigan Ann Arbor, Michigan EFFECT OF PRIOR CREEP ON EFFECT OF PRIOR CREEP ON SHORT-TIME MECHANICAL SHORT-TIME MECHANICAL PROPERTIES OF 17-7PH STAIN- PROPERTIES OF 17-7PH STAINLESS STEEL (RH 950 Condition LESS STEEL (RH 950 Condition Compared to TH 1050 Condition), Compared to TH 1050 Condition), by J.V. Gluck and J.W. Freeman. by J.V.Gluck and J.W. Freeman. March 1959. 82p. incl. illus. March 1959. 82p. incl. illus. tables, 6 refs. (Proj. 7360; Task tables, 6 refs. (Proj. 7360; Task 73604). WADC TR 59-339). 73604). WADC TR 59-339). (Contract AF33(616)-3368). (Contract AF33(616)-3368). Unclassified Report UNCLASSIFIED Unclassified Report UNCLASSIFIED (over) (over) UNCLASSIFIED UNCLASSIFIED University of Michigan University of Michigan Research Institute Research Institute Ann Arbor, Michigan Ann Arbor, Michigan EFFECT OF PRIOR CREEP ON EFFECT OF PRIOR CREEP ON SHORT-TIME MECHANICAL SHORT-TIME MECHANICAL PROPERTIES OF 17-7PH STAIN- PROPERTIES OF 17-7PH STAINLESS STEEL (RH 950 Condition LESS STEEL (RH 950 Condition Compared to TH 1050 Condition), Compared to TH 1050 Condition), by J.V.Gluck and J.W. Freeman. by J. V.Gluck and J.W. Freeman. March 1959. 82p. incl. illus. March 1959. 82p. incl. illus. tables, 6 refs. (Proj. 7360; Task tables, 6 refs. (Proj. 7360; Task 73604). WADC TR 59-339). 73604). WADC TR 59-339). (Contract AF33(616)-3368). (Contract AF33(616)-3368). Unclassified Report UNCLASSIFIED Unclassified Report UNCLASSIFIED (over) (over)

The effect of creep to 2 percent in UNCLASSIFIED The effect of creep to 2 percent in UNCLASSIFIED 100 hours at temperatures from 100 hours at temperatures from 6000 to 900'F was determined on 6000 to 900'F was determined on the tension, compression, and the tension, compression, and tension-impact properties of 17-7 tension-impact properties of 17-7 PH(RH950 Cond. ) at room temper- PH(RH950 Cond. ) at room temperature or the exposure temperature, ature or the exposure temperature. A substantial loss in ductility was A substantial loss in ductility was observed in room temperature ten- observed in room temperature tension tests, Material exposed to sion tests. Material exposed to creep at 600'F exhibited a substan- creep at 600'F exhibited a substantial Bauschinger effect in tension tial Bauschinger effect in tension and compression tests, The loss in and compression tests, The loss in ductility is attributed to stress and/ ductility is attributed to stress and/ or temperature induced aging dur- UNCLASSIFIED or temperature induced aging dur- UNCLASSIFIED ing the creep-exposure, ing the creep-exposure, The effect of creep to 2 percent in UNCLASSIFIED The effect of creep to 2 percent in UNCLASSIFIED 100 hours at temperatures from 100 hours at temperatures from 6000 to 9000F was determined on 6000 to 900~F was determined on the tension, compression, and the tension, compression, and tension-impact properties of 17-7 tension-impact properties of 17-7 PH(RH950 Cond, ) at room temper- PH (RH950 Cond, ) at room temperature or the exposure temperature, ature or the exposure temperature. A substantial loss in ductility was A substantial loss in ductility was observed in room temperature ten- observed in room temperature tension tests, Material exposed to sion tests. Material exposed to creep at 600~F exhibited a substan- creep at 600~F exhibited a substantial Bauschinger effect in tension tial Bauschinger effect in tension and compression tests, The loss in and compression tests, The loss in ductility is attributed to stress and/ ductility is attributed to stress and/ or temperature induced aging dur- UNCLASSIFIED or temperature induced aging dur- UNCLASSIFIED ing the creep-exposure, ing the creep-exposure,

UNIVERSITY OF MICHIGAN 3 9015 03127 2506