ENGINEERING RESEARCH INSTITUTE UNIVERSITY OF MICHIGAN ANN ARBOR. MICH. SIXTH PROGRESS REPORT TO MATERIALS LABORATORY WRIGHT AIR DEVELOPMENT CENTER ON EFFECT OF PRIOR CREEP ON MECHANICAL PROPERTIES OF AIRCRAFT STRUCTURAL METALS by J. V. Gluck H. R, Voorhees J. W,, Freeman. Project 2498 Air Force Contract No, AF33(616)-3368 Supplement 1(57-850) Task No,, 73605 May 25, -.957

SUMMARY This report covers progress under Contract AF33(616)-3368 for the period from February 10, 1957 to May 25, 1957 on a study of the effect of prior-creep )on the short-time mechanical properties of some aircraft structural metals,, Materials presently under study include C-110M titanium alloy and 17-7PH (TH1050 condition) precipitation-hardening stainless steel, During the period covered by this report the draft Summary Report covering the first year of the contract was approved and was reproduced for distribution, Experimental work accomplished during this period included the establishment of base properties in tension and compression for 17-7PH at 800' and 900 F and for C-110M at 650', 700', and 800'F. Room temperature tension-impact tests were run on C —11O0M, Creep tests aimed at establishing total deformation curves for C-110M were completed at 700 and 800~F and are almost complete at 650'F, Tensile tests of C-11OM following unstressed exposure reveal little change in properties beyond a reduction in yield strength after 800 F exposure, Tensile tests at room temperature of discontinued creep specimens of C-110M revealed increases in strength up to 20% after 700'F prior creep, The effects of prior creep on the room temperature tensile properties of 17-7PH have been determined over a wide range of prior deformations Increased amounts of prior creep raised the subsequent tensile and yield strength at each of the test temperatures, Deformations above 1 percent had adverse effects on ductility, Scatter in the data will necessitate replicate testing before exact trends can be established, Improvements in the tension-impact test procedures have been considered and a method for recording stress-strain curves during such tests is under development,

INTRODUCTION This report, the sixth progress report to be issued under Air Force Contract AF33(616)-3368 and the first to be issued under Supplement 1(57-850) to the contract, covers the period from February 10, 1957 to May 25, 1957, The purpose of the investigation is to study the effects of elevated temperature prior creep-exposure on the subsequent mechanical properties of three aircraft structural sheet alloys, The materials and temperatures under study include: 1, Aluminum alloy 2024-T86 at 350' 400, and 500'F 2, Titanium alloy C1.10M at 650, 700' and 800~F 3, Stainless steel 17-7PH (TH1050 condition) at 600' 800', and 900F, The first phase of the contract involved study of the aluminum alloy and survey work on the stainless steel, The results of that investigation are contained in WADC Technical Report 57-150, pre-print copies of which will be available in June, 1957, Both stressed and unstressed exposure tests are being conducted for times of 10, 50, or 100 hours. Stressed exposures are carried out at the nominal stresses to give 0, 5, 1, 0, 2, 0, and 3, 0 percent total deformation in the specified time period, The total deformation is defined as all deformation, elastic and plastic, that occurs during the application of the load and during the creep of the specimen at the testing stress and temperature, By fixing stress, temperature and time, it is necessary to accept whatever total deformation is o:ta:in.dl, Properties are correlated with respect to actual deformation, After the specified exposure, the following properties are evaluated at both room temperature and the temperature of prior exposure; short-time tensile properties; short-time compression properties; tension-impact strength; and

2 also hardness determinations at room temperature, Where significant effects are noted, metallurgical studies will be employed to explain their cause, The stresses for the nominal exposure conditions are determined from curves of stress versus time for the specified total deformation, established for each material at each temperature of interest, The properties of the exposed material are compared with the properties of the unexposed material which are established through from 7 to 10 tests of samples chosen randomly from the various sheets of material,.. In many cases, replicate exposure tests are run in order to ensure generality of the results. As specified in the contract, the test materials were procured as approximately 0, 064-inch thick sheets. The testing direction was dictated by the desire to test each material in its nominally weaker direction, The aluminum and stainless steel are tested crosswise to the sheet rolling direction, while the titanium alloy is tested parallel to the sheet rolling direction, The aluminum and titanium alloys are tested as furnished by the manufacturer, the aluminum alloy was cold-worked and artificially aged and the titanium alloy hot-rolled and annealed. The stainless steel was heat treated to the TH 1050 condition at the University, This treatment is one of double aging, first at 1400'F and then at 1050'F, Test Materials and Specimen Preparation A complete discussion of the test materials and the specimen preparation is contained in the First Summary Report, WADC TR 57-150, The materials as received conformed to their nominal composition limits, The 17-7PH alloy is a precipitation hardening stainless steel containing 16-18 percent chromium, 6, 5-7, 75 percent nickel9 0, 75-1, 5 percent aluminum, and 1 percent manganese-, It was received in the annealed condition and heat treated to the TH 1050 condition as mentioned previously,

3 The titanium alloy C lIOM is a'binary alloy containing 7-9 percent manganese, The aluminum alloy S 2024-'T86, tested under the first phase of the contract contained3, 8-4, 9 percent copper, 0, 3-0, 9 percent manganese, and 1, 2-1, 8 percent magnesium, Sheet sampling procedures were developed for each material in order to ensure randomness of the test results, Each specimen was given a code number denoting- the individual sheet from which it came and the position within the sheet, A modular, repeating sampling system was applied to each sheet, The specimen number code identifies sheet number, module number,. and position with the module —in that order, Exposure specimens were so designed that the specimens for the subsequent tension, compression, and tension-impact tests could be machined from them with minimum difficulty. The specimens were milled to rough dimensions and then the shoulder radii and gage sections were ground to the finished dimensions, Test Equipment and Proc edures A discussion of the test equipment and procedures developed in the first year of the contract was presented in the Summary Report and will not be repeated here, In the period covered by this report, work was initiated on modification and extension of the previously-developed tension-impact test procedures The work included the improvement of the elevated temperature test procedure and the development of equipment for recording stress-strain data during tension-impact tests, The original plan for tension impact testing at elevated temperatures contemplated heating the specimen while it was attached to the pendulum head, A furnace was adapted to allow heating the specimen, its gripping assembly, and the impact striker while all were in the vertical position prior to release of the pendulum latch. Unfortunately, the combination of the high thermal conductivity of the aluminum specimens and the large unheated mass of the pendulum head caused a large temperature difference over the length of the specimen gage section, The heating elements of the furnace did not permit compensation for this difference,

4 As an expedient the tests of the aluminum alloy were conducted by heating the specimen assembly in a separate furnace and then attaching it to the pendulum head while it was hot, Compensation was made for the necessary time delay and fairly consistent values of impact energy were obtained once-the operator had gained proficiency in handling the hot specimen assembly while wearing asbestos gloves, Nevertheless, it was felt that improvement of this procedure was desirable0, Present plans contemplate the building of a small furnace of the split type that will. just fit around. the specimen grips, IHeating is to be accomplished with tubular heating elements with provision for both fixed and sliding elements in the annulus of the furnace, Temperature distribution is to be achieved by varying the longitudinal position of the sliding elements,, In. this way, heating of the specimen could be done wh:ile it, was attached to the pendulum, 1The elements were n o rder for the greater part of the report period and only recently received,, Consequently co nstruction of the furnace is just under way,, Other effort ha s been devoted to developing procedures for recording roomn temper'ature stress-strain curves in tension-impact testing, The m.ethod contemplated i-:.:ilzes electrical strain gages arranged in a nominally balanced Wheatstone Bridge c onfiguration A voltage is a.pplied across one diagonal of the bridge and a deformation of the sensing element causes an output across the other diagonal of the bridge, Two circuits are to be used, One bridge is to be used for stress measurements, To ac crm.plsh, this a tension l.ink of square cross ssection. was ach.ined f1'rom 17-22 AV steel9 a material with a high proportional limit9 and the strain gages applied to this in the forn of a temperature compensating bridge circuit, The link was designed to attach between the impact holdin.g jaws and the pendulum head,, The anticipated stresses fall well within the elastic range of the tension link a.nd thus the lknowledge of the electrical characteristics of the bridge and the elastic mnodulus of the link allow conversion of the deformation of the link to the load on the specimen0L,

5 The deformation of the tension-impact specimen is to be measured by two strain gages attached to opposite sides of the specimen gage section and wired in series to an external bridge circuit, the other three legs of which are constructed of similar strain gages. This type of gage mounting eliminates the extraneous effects of any bending since one gage is in compression and the other in tension should bending occur, The net output is that due to pure tension, Initial tests of the equipment have been conducted with a tensile machine, A Moseley XYY Recorder has been used to record stress-strain curves. Input voltages to the bridge circuits are supplied by mercury dry cells which are noted for their constant voltage, The initial tests have been directed toward the establishment of the circuitry and the reconciliation of the actual output voltages with those computed from the bridge characteristics, gage factors, the input voltages, and the modulii of the materials under consideration. Fair results have been obtained, In actual tension-impact testing it is anticipated that the strain rates encountered will be beyond the range of pen travel speed of the X-Y!Recorder, The use of recording oscilloscopic equipment is anticipated for these tests. RESULTS AND DISCUSSION Base Properties of 17 7PH Tensile and compression tests at 600' 800', and 900'F were completed on samples of 17-7PH stainless steel in the TH 1050 condition, The purpose of these tests was to establish the base properties of the as-treated material prior to creep=exposure, The elevated temperature tensile data are summarized in Table 1 and the compression test data are summarized in Table 2, The average room temperature properties previously determined for this material are included in each table0 Figure 1 presents a plot of the tensile properties and compression yield strength versus test temperature,

6 Tensile test results at 800' and 900"F show somewhat less scatter within individual sheets than did the 600IF data, however, the agreement in average properties from sheet to sheet is about the same for all test temperatures, The drop in strength with temperature was about the same for the ultimate tensile and yield strengths, however, the compressive yield strength showed a somewhat greater temperature dependence over the range from 600~ to 900'F, A small drop in tensile test elongation from that at room temperature was found at 600EF, while at 800" and 900eF the elongation showed a substantial increase. The reduction of area data included in Table 1 show a similar trend, At both room temperature and 600'F, the compression yield strength was appreciably higher than the ultimate tensile and tensile yield strength. The greater temperature dependency of the compression strength reduced its value to about that of the tensile strength at 800' and 90-0F, Modulus values included in Tables 1 and 2 were computed from the slopes of the stress-strain curves recorded for each test, No consistent difference appears to be evident between the tension and compression modulus at the various test temperatures, Effect of Unstressed Exposure on Elevated Temperature Tensile Properties of 17-7PH The results of tensile tests conducted at 600eF on samples of 17-7PH (TH 1050 condition) given various unstressed exposures at 600~F are presented in Table 3, Exposure times of 10, 50, or 100 hours were used, The data are incomplete since the duplicate specimens exposed at each condition have not yet been tested, The available results indicate that exposure caused a drop in the tensile and yield strength and a slight increase in ductility, The apparent minimum strength for 50 hours exposure may be due to testing scatter and should not be taken seriously until the results of the additional tests are available,

7 Effect of Prior Creep on Tensile Properties of 17-7PH............ Iz:.,~. ~_.__... ___.__ ~ -...:. The results presently available on the effects of prior creep on the tensile properties of 17-7PH (TH 1050 condition) are presented in Table 4, These results include a fairly complete coverage of the temperatures, times, and deformations as they affect room temperature properties and some sparse data on the elevated temperature properties0 Inasmuch as replicate tests are planned for many of these conditions, no plots have been prepared from these data, Examination of the results shows inconsistencies in the tensile and yield strengths that are probably due to testing and material scatter, It is difficult to establish exact trends for changes in strength properties from these initial data. Cursory examination indicates that increased amounts of prior creep tend to raise the room temperature tensile and yield strength, following exposure at each of the test temperatures, Prior deformations above 1 percent appear to reduce the ductility of the material by appreciable amounts, This is especially noticeable at 600~ and 800'F,, The elevated temperature test data suggest that there may be a maximum in the relation between strength and prior deformation. however, the ductility properties do not appear to be seriously affected, Base Properties of CilO1M Tests to determine the base properties of C 110OM titanium alloy at 650' 700 and 800F were completed for the tensile properties and compression properties, The room temperature tensionimpact properties have also been determined, The tensile test data are summarized in Table 5, the compression test data in Table 6, and the tension impact data in Table 7, A plot of the effect of test temperature on the tensile and compressive properties is presented in Figure 2. The tensile data show good consistency both within individual sheets and between sheets, An almost linear drop in tensile and yield strength with temperature was noted over the range studied, A slight decrease in ductility was observed at 650~ and 700~ over the room temperature value and a sharp increase in ductility was found at 800~F,

8 The compression yield strength dropped similar to the tensile strength between room temperature and 650F, however, the decrease with temperature leveled off at 700' and 800'F, In contrast to the data for the 17.7PH stainless steel, the compression yield strength was substantially lower than the tensile yield strength. The modulus values showed a moderate decrease with increasing test temperature, The compression modulus values were not noticeably different than the tensile modulii, The room temperature tension-impact data in Table 7 show good agreement when compared on the basis of sheet averages, Individual tests within sheets exhibited scatter, particularly in the case of sheet 2, Effect of Unstressed Exposure on Tensile Properties of Cll0M Samples of Cl10M have been exposed at 650% 700, or 800' for 10, 50, or 100 hours and then tensile tested at either room temperature or the temperature of prior exposure,, At least one room temperature test has been completed for each exposure condition and subsequent tests at 650~ and 800~F have also been performed, The results of these tests are summarized in Table 8 and the data are plotted in Figure 3, Replicate tests are planned for several conditions in order to check the r es ults As Figure 3 indicates, the unstressed exposure had negligible effect on the room temperature tensile strength, while the room temperature yield strength was only noticeably affected by prior exposure at 800 F,, The tensile and yield strengths at 650'F were also little affected by prior exposure,. The 800~F tensile strength showed a slight increase with exposure time, while the 800'F yield strength dropped for exposures up to 50 hours and then recovered at 100 hours — but not back to its original value,

9 As mentioned above, further testing is contemplated to confirm these results, however, it appears that unstressed exposure had little serious effect other than a possible reduction of yield strength after 800'F exposure, The ductility data in Table 8 showed no significant effects following unstressed exposure, Creep Tests of CllOM Creep tests have been run on specimens of CllOM at 650, 700' and 800'F in order to establish the curves of stress versus time for given total deformations, to be used for selection of stresses for creep-exposure tests, The results of tests conducted to data are summarized in Table 9 and plotted in Figure 4, None of the tests were run to rupture, the test being discontinued once the limit of useful information had been reached, The discontinued creep specimens were then tensile tested and the total test time9 final deformation, and subsequent tensile p3ioperties for each specimen have been included in Table 9. This tabulation gives an idea of the relative amount of property change that might be expected from controlled-condition stress e1 exposure tests. Curves of 0,, 5, 1, 2, and 3 percent total deformation from 10 to 100 hours have been established with fairly good success at 700'and 800'F, (See Fig. 4) At 650"F,. only the 0, 5 and 1. 0 percent curves have been tentatively established, Following the loading deformation, the creep of this alloy at 650~F is very slow, The scatter in test points has been relatively slight with the exception of some high stress tests at 650~ and 700~F, Further testing is contemplated at 650'F, The subs equent room temperature tensile properties of these samples show instances of increased tensile and yield strength following prior creep. This was most noticeable for the 700'F samples. The increase -in strength was moderate and was accompanied by some decrease in ductility. In a few cases an apparent slight decrease in strength was noted, however, this may be due to testing scatter, What appears to be a very severe loss in yield strength was noted for the sample tested after almost 1300 hours at' 800~F, Generally, the increased strength was within about 15 percent of the base value,

10 FUTURE WORK Work planned for the near future includes the following: 1, Preliminary copies of the Summary Report, WADC TR 57-150, will be distributed as soon as they are received from the printer. 2. The establishment of total deformation prbpieties of C-10M at 650~F will be completed. 3, The furnace for tension-impact testing will be constructed and the development of strain-strain recording equipment will be continued, 4. Replicate stressed exposure tests of 17-7PH will be run to allow establishment of trends in the changes in room temperature properties. Testing of elevated temperature properties will be continued. Primary emphasis will be placed on evaluation of 17-7PH, 5, The evaluation of the effects of prior creep on compression properties will be initiated,

TABLE 1 ELEVATED TEMPERATURE TENSILE TEST DATA 17-7PH (TH 1050 CONDITION) AS TREATED 0,2% offset Test Ult, Tensile Yield Strength Elongation Reduction of Modulus, E Temp (-F) Spec. No. Strength(psi) (psi) (%/2 inches) Area (%) 106 (psi) room Average 203,100 193,050 7 1 18,2 28.6 600 1G-T3 179,600 168,500 4.0 12, 6 28 1 1P-T22 175,300 169,500 5,8 17,2 28.2 1P-T26 163,600 158,900 5.0 15.0 27.9 Average 172,833 165,633 4.9 14,9 28,1 2E-T2 183,000 168,700 4.5 16. 1 29,3 2J-T4 156,900 148,000 5.2 14.8 27.4 2S-T4 186,900 179,000 5.2 16.1 27.2 Average 175,600 165,233 5.0 15.7 28.0 3A-T3 157,100 147,900 2 5 16.4 29.4 3P-T3 186,000 178,600 6.2 15.2 27,9 3P-T4 159,200 150,000 4.5 12.5 28.6 Average 167,433 158,833 4.4 14.7 28.6 Average -9 171,989 163,233 4.8 15.1 28.2 tests 800 1P-T25 150,000 136,000 13.7 30,6 27.6 2E-T3 148,000 138,000 15.5 28.8 26.0 2J-T2 153,000 146,000 11.0 21.0 23.7 2R-T4 148,000 138,000 10.8 26.8 23.6 Average 149,667 140,667 12,4 25.5 24.4 3F-T5 148,000 138,000 12.8 29,2 23.0 3P-T2 147,000 137,000 9,5 27.9 24.8 3B-T6 140,000 132,000 9.3 23.5 22.2 Average 145,000 135,667 10.5 26.9 23.3 Average - 3 148,223 137,444 12.2 27.6 25.1 sheets 900 1K-TI 118,200 109,100 17.5 38.6 20.9 1Q-T24 123,000 111,000 21.3 39 2 21. 7 Average 120,.800 110,500 18.4 38.9 21.3 2J-T1 125,000 112,000 32.3 43.0 21.6 2S-T5 129,000 118,000 11.5 35.5 21.4 Average. 127,000 115,000 21.9 39,2 21.5 3B-T7 117,300 109,000 17.5 38.6 21.0 3L-T3 121,500 109,000 16.5 41.0 22.2 3Q-T2 123,000 112,000 20,5 38.3 22.5 Average 120,600 111,000 18.2 39,3 21,9 Average - 3 122,800 112,133 19.8 39 1 21.6 sheets

TABLE 2 ELEVATED TEMPERATURE COMPRESSION TEST DATA 17-7PH (TH 1050 CONDITION) AS TREATED 0.2% offset Test Yield Strength Modulus, E Temp (*F) Spec. No. (psi) 10 (psi) room Average 220,777 29.8 600 1U-X2 184,000 25.6 1 T-X44 182,000 26.2 Average 183,000 25.9 2C-X2 190,000 25.8 2T-X2 190,000 25.8 Average 190,000 25.8 3D-X2 181,000 26.2 3R-X44 187,500 26.2 3K-X2 184,000 26.2 Average 184,167 26.2 Average - 3 sheets 185,723 26.0 800 1D-X44 146,000 24.4 1N-X44 149,000 24.4 IU-X44 148,000 24.4 Average 147,667 24.4 2U-X44 144,000 24.7 2G-X2 144,000 24.7 2A-X44 146,000 23.8 Average 144,667 24.4 3K-X44 146,200 25.4 3T-X44 147,000 24.4 3D-X44 151,000 24.8 Average 148,067 24.9 Average - 3 sheets 146,800 24.6 900 1N-X2 107,000 23.0 1T-X3 112,000 23.1 1T-X2 114,000 23.1 Average 111,000 23.1 2C-X44 110,000 23.0 2U-X2 117,500 23.5 2L-X2 119,000 22.6 Average 115,500 23.0 3D-X3 112,000 23.2 3R-X2 115,500 23.0 3T-X2 118,000 23,2 Average 115,133 23.1 Average - 3 sheets 113,877 23.1

TABLE 3 EFFECT OF UNSTRESSED EXPOSURE AT 600"F ON SUBSEQUENT 600F TENSILE PROPERTIES OF 17-7PH (TH 1050 CONDITION) Exposure Exposure Ult, 0,2% offset Temp Time Test Temp Tensile Yield Strength Elongation Reduction of Modulus (F) (hr) (F) Spec, No, (psi) (psi) (%/2 inches) Area (%) Ex 10 (psi) 600 nil 600 average 171,989 163,233 4, 8 15.1 28,2 600 10 600 1D-T3 159,000 151,000 5.5 15.2 25,4 50 600 2U-T3 148,000 139,500 6.5 19.6 26.0 100 600 2U-T6 161,000 153,000 5,.0 18,3 25,8 Note: Additional specimen exposed for each condition but not yet tested,

TABLE I EFFECT OF ELEVATED TEMPERATURE STRESSED EXPOSURE ON SUBSEQUENT TENSILE PROPERTIES 01' 17-7PH (TH 1050 CONDITION) Subsequent Room Temperature Properties Nominal Exposure Conditions Actual Exposure Conditions Ult. Tensile 0. 2% offset Temp Time TotaI 1e-l~.- Time Stress Load Del. Creep Del. Total Def. Strength Yield Strength Elongation Reduction of Area Modulus, E Hardness (*F) (hr) (%) Spec. No. (hr) (psi) () () (/0% Si)si) (psi) ( _%/2 inches) (%)_ 10~ (psi) R"C" 600 10 0.5 2U-T5 10.0 118,000 0.43 0.02 0.45 186,500 179,000 5.5 20.5 29.6 41.1 10 1.0 3D-T6 10.0 159,000 0.69 0.35 1.004 210,000 210,000 4.0 16.3 29.7 45.0 10 2.0 ID-T6 10.0 167,000 0.77 0.99 1.76 211,000 211,000 2.3 13.3 28.0 43.3 2T-T5 -- 167,000 rupture on load. -- -- -- - - - 10 3.0 20-T4 10.2 173,000 0.98 1.53 2.51 227,000 227,000 2.0 11.2 28.5 44.7 3R-T6 173,000 rupture at 6. 5 hours -- -- - - - - 50 0.5 1D-T5 50.1 116,000 0.43 0.06 0.49 205,000 195,000 7.0 16.7 30.0 45.1 50 1.0 3K-T2 50.0 150,000 0.54 0.32 0.86 205,000 205,000 3.2 13.8 29. 2 44.2 50 2.0 2A-T3 -- 160,000 rupture on load -- -- -- -- -- -- -- 50 3.0 3T-T5 50.0 164,000 0.63 1.18 1,81 216,000 216,000 2.2 10.5 29.9 44.0 100 0.5 3D-Tl 100.0 114,500 0.39 0.05 0.44 191,500 186,000 9.8 17.2 29.6 45.0 100 1.0 1D-T4 99.9 146,000 0.55 0.31 0.86 218,060 218,000 3.0 10.7 29.2 42.9 100 2.0 2N-T1 100.5 157,000 0.60 1.28 1.88 223,000 223,000 1.5 13.7 29.4 3Q-T7 104.9 157,000 -- -- 3.8-1 209,000 -- 2.0 8.6 30.3 41.1 3H-T4 -- 157,000 rupture at 17.8 hours - - - - 1P-T24 99.9 157,000 -- -- 5.30 217,500 188,500 2.0 5.8 28.9 42.8 100 3.0 2C-TI 100.0 161,000 0.74 3.68 4.42 218,000 218,000 1.8 6.3 29.0 43.9 800 10 0.5 3K-T6 10.2 70,000 0.29 0.13 0.52 212,000 206,500 4.3 13.1 29.8 42. 6 10 1.0 2G-T5 10.2 88,000 0.36 0.68 1.04 191,500 188,000 6.5 16.6 30.2 41.1 10 2.0 1J-T6 10.0 98,000 0.35 1.86 2.21 208,000 207,000 3.5 16.5 28.4 45.5 10 3.0 3R-T5 10.0 101,000 0.42 2.08 2.55 234,000 222,000 3.0 14.2 30.2 48.7 50 0.5 IN-T1 50.0 62,000 0.23 0.15 0.98 187,000 174,000 9.5 17.0 29.4 42.3 50 1.0 2A-T1 50.0 75,000 0.32 0.64 0.96 221,000 207,000 9.5 16.6 29.5 47.4 50 2.0 3R-T2 50.0 86,000 0.35 1.43 1.78 172,000 171,000 3.0 16.4 29.2 45.0 50 3.0 1J-T4 50.1 91,000 0.33 2.77 3.10 216,000 212,000 3.5 17.0 29.6 46.9 100 0.5 3P-T5 100.0 59,000 0.23 0.15 0.48 208,000 204,000 3.8 17.6 30.3 -- 100 1.0 3H-T5 100.0 70,000 0.27 0.62 0.89 220,000 215,000 3.5 14.0 32.1 -- 100 2,0 3P-TI 102.6 81,000 0.31 1.81 2.12 223,000 229,000 3.5 12.1 29.9 46.7 2S-T6 102.1 81,000 0.32 1.56 1.88 227,000 222, 000 4.2 15.8 30.2 46.7 100 3.0 3L-T2 100.0 85,000 0.32 2.13 2.45 218,000 214,000 2.2 20.2 30.1 -- 900 10 0.5 2L-T6 10. 1 46,000 0.21 0.36 0.57 228,000 218,000 2.2 3.6 30.3 46.3 10 1.0 IJ-T2 10. 1 55,000 0.24 0.89 1.13 215,000 207,000 4.0 15. 2 29.9 44.0 10 2.0 3K-TI 10.0 62,000 0.28 2.03 2.31 221,500 219,000 3.5 12.7 29.4 47.0 10 3.0 1N-T6 10.1 68,000 0.27 3.09 3.36 201,000 195,000 4.8 17.6 29.2 43.1 50 0.5 2ULT4 50.0 40,000 0. 17 0.45 0.62 235,000 228,000 7.0 9.8 30.0 48.4 50 1.0 2A-T2 50.0 48,500 0.20 0.91 1. 11 200,000 191,500 9.8 18.0 29.4 44.3 50 2.0 1D-T2 49.9 54,000 0.29 1.48 1.77 205,000 197,000 6.8 17.0 29.2 47.5 50 3.0 3R-T1 50.0 56,000 0.25 2.15 2.40 195,000 189,000 8.0 19.6 30.0 43.0 100 0.5 3G-T5 100.0 37,000 0.14 0.33 0.47 204,000 196,000 4.5 17.6 29.2 100 1.0 3A-T4 100.0 46,000 -- -- 0.94 228,000 220,000 4.5 14.4 30.1 46.0 2R-TI 100.0 49,000 0.19 1.36 1.55 214,000 209,000 6.5 16.7 29.9 45. 3 100 2.0 3G-T2 100.1 50,000 0.22 1.82 2.04 224,000 219,000 4.0 15.2 29.7 46.8 1Q-T22 100.0 50,000 0.20 2.13 2.33 235,000 230,000 4.0 13.1 30,0 48 1 100 3.0 3Q-T4 100.0 52,000 0.23 2.07 2.30 221,000 219,000 5.0 14.9 31.0 Subsequent 800'F Properties 800 100 1.0 2T-T6 99.9 70,000 0.26 0.57 0.83 149,000 140,000 16.8 27.7 22.6 47.6 100 2.0 3T-T1 100.0 81,000 0.32 1.76 2.08 144,000 137,000 14.8 28.8 23.3 46.5 Subsequent 900'F Properties 900 100 0.5 1D-TI 100.2 37,000 0.16 0.43 0.59 132,000 119,000 17.8 28.4 23.0 45.6 10 3.0 2G-T6 10. 1 68,000 0.31 2.49 2.80 125,000 117,000 14.5 31.3 21.3 43.9

TABLE 5 TENSILE TEST DATA FOR C11OM AS PRODUCED 0.2% offset Test Ult. Tensile Yield Strength Elongation Reduction of Modulus, E Temp ('F) Spec. No. Strength (psi) (psi) (%/ 2 inches) Area (%) 106 (psi) room 1A-9T 145,000 140,000 22.0 35.2 16.8 1AB-17T 144,000 139,000 24.0 32.4 16.0 1C-13T 152,000 144,000 21.5 30,2 16. 8 Average 147,000 141,000 23.5 32.6 16.5 2C-5T 146,000 144,000 22.3 29.6 16.8 2C-20T 147,000 143,000 21,7 31,6 16.4 2A-28T 146,000 142,000 20.5 32.0 16.9 Average 146,333 143,000 21.5 31.1 16.7 3C-20T 146,000 142,000 22.7 26.4 15.8 3A-13T 147,000 145,000 21. 5 30,8 16.4 3A-34T 151,000 147,000 22.5 33.3 16.6 Average 148,000 144,667 22.2 30.1 16.3 Average - 9 tests 146,211 142,889 22.4 31.3 16.5 650 1C-24T 108,000 92,000 19.5 28.0 13.4 1A-32T 109,000 95,000 21.0 33.3 13.8 1C-9T 107,000 -- 15.1 31.6 13.6 Average 108,000 93,500 18.5 31.0 13. 5 2A-24T 112,000 97,000 14.5 29.0 13.6 2C-13T 111,000 97,000 17.5 24.7 13.5 2A-5T 112,000 94,500 16.0 24.0 13.9 Average 111,667 96,167 16.0 25.9 13.7 3C-9T 114,000 100,000 17.0 21,6 13.8 3C-34T 111,000 96,700 17.7 26.6 13.0 3A-1T 112,000 98,600 16.7 24.8 13,6 Average 112,333 98,433 17.1 24.3 13.5 Average - 9 tests 110,667 96,033 17.2 27.1 13.6 700 1C-1T 94,900 83,500 17.2 36.4 12.3 1A-13T 106,000 91,000 19,0 34.1 13. 7 1A-28T 105,000 92,700 21.2 31.4 13.6 Average 101,967 89,067 19.1 33.9 13.2 2C-36T 107,000 95,700 16.1 32.7 13.6 2C-24T 107,000 91,400 17.0 32.8 13.3 2AB-17T 106,000 91,500 15.8 29.6 13.5 Average 106,667 92,867 16.3 31.8 13.5 3C-17T 107,000 97,500 16.0 32,4 12.8 3A-24T 109,000 96,700 18.7 2'. 2 13.4 3A-9T 108,000 94,000 19.0 28.0 12.7 Average 108,000 96,067 17.9 29.9 13.0 Average - 9 tests 105,545 92,667 17.8 31.9 13.2 800 1C-28T 90,000 83,000 39.7 51.0 11.8 1C-17T 90,000 85,000 25.4 47.3 11.8 1A-20T 90,600 82,000 29.0 49.5 12.0 Average 90,200 83,333 31.4 49.3 11.9 2A-9T 91,000 79,700 30,0 48.7 12.0 2A-36T 93,000 84,500 46.5 51.0 12 3 2C-28T 93,200 85,500 32.0 49.7 11,3 Average 92,400 83,233 36.2 49.8 11.9 3C-1T 95,000 84,800 24.7 45.3 11.2 3C-28T 95,300 85,700 30.8 47.2 11. 1 3A-20T 94,000 87,000 21.3 43.4 11.2 Average 94,766 85,833 25.6 45.3 11.2 Average - 9 tests 92,455 84,133 31.1 48.1 11.7

TABLE 6 COMPRESSION TEST DATA FOR C110M AS PRODUCED 0, 2% offset Compression Test Yield Strength Modulus, E Temp ('F) Spec. No. (psi) 10~ (psi) room 1C-24C 108,000 15.8 1A-5C 107,000 16.2 1A-13C 108,000 16.0 Average 107,667 16.0 2C-24 C 107,000 16.7 2C-9C 109,000 15.9 2A-28C 105,000 16.4 Average 107,000 16.3 3A-24C 108,000 16.0 3C-32C 110,000 16.4 3A-9C 111,000 16.1 Average 109,667 16.2 Average -9 tests 108,111 16.2 650 IA-24C 63,000 12.9 IC-32C 58,400 12.6 1C-5C 57,600 12.8 Average 59,667 12.8 2C-28C 58,400 12.9 2A-9C 55,800 13. 2 2A-5C 68,400 13.2 Average 60,800 13. 1 3A-13C 58,600 13.2 3C-24C 71,000 13.3 3C-5C 57,800 12. 8 Average 62,400 13.1 Average -9 tests 61,000 13.0 700 1A-28C 57,900 12.7 IC-13C 53,800 12.5 IA-9C 55,400 12.3 Average 55,700 12. 5 2C-13C 60,600 12.9 2A-24C -- 12. 5 2C-5C 59,400 12.5 Average 60,000 12. 6 3A-32C 54,600 12 7 3C-28C 59,000 12. 5 3C-6C -- 12.4 Average 56,800 12.5 Average -7 tests 57,243 12.5 800 1C-28C 53,900 1. 8 1C-9C 55,100 11.8 1A-32C 53,800 11 6 Average 54,300 11.7 2C-32C 62,500 12.0 2A-32C 55,1 00 11.7 2A-13C 55,600 11.9 Average 57,800 11.9 3A-28C 59,800 12.1 3C-13C - -- 3A-5C 54,600 11 7 Average 57,200 11.9 Average - 8 tests 56,337 11.8

TABLE 7 SMOOTH-BAR TENSION-IMPA C T TEST DATA AT ROOM TEMPERATURE FOR CI1OM AS PRODUCED Tension-Impact Strength Spec. No. (ft-lb) 1A 5M 48 1A -13-M 50 1C 24M 69 Average 55,6 2A -28M 67 2C -5M2 64 2C-9M 37 Average 56,.0 3A-9M 50 3A-24M 62 3C-28M 58 Average- 9 tests 56.1

TABLE 8 EFFECT OF UNSTRESSED EXPOSURE ON SUBSEQUENT TENSILE PROPER TIES OF C 1 10M Subsequent Tensile Properties Exposure Conditions. 0,. 2% offset Hard-'emp Time Test Temp Ult, tensile Yield Strength Elongation Reduction of ModulusE ness (0F) (hr) Spec. No. ('F) Strength (psi) (psi) (%/2 inches) Area (%) 106, psi R'C" 650 10 2A-31A room 144,000 1369000 25,3 31. 4 15 1 35.3 50 1C-26C room 147,500 140,700 23.3 35,6 15,4 37,2 100 2A-21A room 143,400 136,800 24.0 32,2 15,5 35.8 10 3C-11C 650 112,700 94,900 20.5 26.0 13,7 35.4 50 2A-B21 650 111,500 94,500 17.5 27.6 12.9 34.5 100 2A-B7 650 114,000 97,000 22.5 26.3 12,9 35.8 700 10 1C-D15 room 143,000 140,000 23,8 34.0 15,4 39.1 50 2C-21C room 1499000 137,500 23.0 33,2 16.1 35.8 100 1A~3A room 146,500 140,000 19. 5 32,0 15.4 38.5 800 10 1Al15A room 146,000 133,000 24.0 35.7 15.1 35 1 50 1C-D3 room 144,000 129,000 23,3 31,8 15,0 34,9 100 2C-D31 room 147,000 125,000 19.3 29.2 15.7 34,1 10 3A-B33 800 91,600 74,400 22,3 48.6 11,3 34.7 50 2A-B31 800 92,200 68,000 23,5 45.0 11.4 32,8 100 3A-18A 800 96,500 78,200 29.5 43.4 11.2

TABLE 9 TOTAL NEFORMATION DATA AND RETAINED TENSILE PROPERTIES AT ROOM TEMPERATURE FOR CREEP TESTS OF C110M Subsequent Room Temperature Tensile Properties Loading Time to Reach Indicated Total Total Ult. Tensile 0.2% offset Test Stress Deformation Deformation (hrs) Test Time Deformation Strength Yield Strength Elongation Reduction of Area Modulus, E Hardness Temp (F) Spec. No. (psi) (%) 0.5%1 1.O 2,0%o 3.0% (hrs) (%) (psi) (p)i) (%/2 inches) (%) 106 (psi) R"C" 650 1C-32T 105,000 in progress -- -- -- -- -- -- -- -- 3A-28T 95,000 0.84 -- 13.5 125.5 -- 166 2.63 165, 000 160, 000 12.2 23.9 15.9 39.0 1A-36T 85,000 0.68 -- 110 -- -- 142 1.10 144,000 141,500 20,0 32.6 15.0 38.4 2A-32T 75,000 0.60 -- 125 -- -- 142 1.,05 164,000 159,000 14.5 22.8 16.8 3C-5T 70,000 0.56 -- 290 -- -- 307 1.03 151,000 145,000 19.7 27.9 15.4 1A-5T 60,000 0.48 5 -- -- -- 216 0.68 152,000 145,000 19.3 29.8 15.6 2A-1T 55,000 0.42 66.5 -- -- -- 142 0.53 146,000 140,000 15.8 31,.2 15.8 36,1 700 3C-24T 90,000 0.86 -- 0.4 12.9 25 * 51 5.0 * -- -- -- -- -- 3AB-17T 80,000 0.65 -- 22.2 47* 68 * 71 3.1 * 164,000 158,000 13.0 22,.0 15.2 39.2 2A-13T 75,000 0.63 -- 17 46 64 147 6.0* 174,200 164,800 7.3 17.3 16.5 2C-32T 65,000 0,52 -- 41 94 127 143 3.49 170,000 151,000 16,.8 26.0 16.1 3A-5T 60,000 0,.43 5 49 102 142 210 4.,8* 169,000 149,000 16.5 21.2 16.1 1C-5T 50,000 0.36 28 108 220 -- 242 2.18 167,000 151,000 15.7 25.6 16.9 2C-9T 40,000 0.30 63 193 -- -- 193 1.10 158,000 140,000 17.5 27.0 16.6 IA-1T 35,000 0,.21 110 -- -- -- 139 0,.58 149,000 134,000 18.0 27.4 15.5 800 3C-13T 35,000 0.30 1 3.2 7.6 12.2 46 6.60 151,000 140,000 19.3 25.2 15. 9 2A-20T 30,000 0.24 3 8,.5 17,.5 26 117 10 * 151,000 138,000 20.3 28,.6 15, 0 1A-24T 25,000 0,.18 4 11 27. 5 46.5 123 6,.40 158,000 137,000 24,.0 31,4 17.2 3C-32T 20,000 0.18 11 29 87 160 169 3,.10 145,000 130,000 19.8 21,.4 16.2 3A-32T 15, 000 0.07 20 64 314 -- 358 2,.11 143, 000 125, 000 23,.0 25.2 15.2 33.2 2C-IT 10,000 0.09 52,.5 296 -- -- 307 1.02 150,000 132,000 30.0 25. 5 16. 5 1C-20T 5,000 0,.05 1140 -- -- -- 1292 0.52 135,000 67,700 (?) 23.8 33. 5 16.3 35.9 * Estimate by extrapolation.

220 ~~~~^~21 Compression Yield ~200.I.- ^ Strength 200 Ultimate 190 _.__Tensile' -Strength 180 Tensile Yield Strength 170 160 ISOib 03 150. 140 \'\~~ S~ 130- ^ 0'2' 120 -/ N 110 10 Tensile Test Elongation 0. 4-, 100 90 0 0 100 200 300 400 500 600 700 800 900 Teat Temperature - *F Figure 1. -Effect of Test Temperature on Tensile and Compressive Properties of 17-7PH (TH 1050 Condition) As Treated.

150 140 130 Tensile Strength 120 Tensile 2 *^ yield'*^ Strength 110 ~100 Compression Yield ^ 90 - ^- Strength ~k 80 70~~~~~~~~~~- 40 70.'^~- / *~ Reduction of Area 60 Elongation 502 a 40 Each point is av,,erage of~ 7 7 9 tests.,__ i __ - _ * -- sf -- o1 ---- I --- I --— ^~ —-- — "5OI., - 70 ~5 0 ~~100 200 300 400 500 60070 Test Temperature - *F Figure 2. - Effect of Test Temperature on Mechanical Properties of Annealed CllOM (As-Received).

Tests at Exposure Temperature Tests at Room Temperature Yield Strength at Tensile Strength at Yield Strength at Room Tensile Strength at Room Exposure Temperature Exposure Tempt*ature Temperature - 1000 psi Temperature - 1000 psi 1000 psi 1000 psi I' o0 NO 00 W0~~ ~' oNo o i U N L 0 0 0 0~~~~~~ 0 0 0 0) 0 0 0 0 0 C) N 0 CD OC CC) (-'D (DT (a 0 ~CD CD r ot 4 HCD CD C?'CA 00 C0~ 01~~~~~~~~~~~~~~~~~~~~ 0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~0 1'10 00 MlJ 0 i'1 CD) 00 Vi C \ t)CD'-'C 11CD 1 i CD 6 ~

100 I lo I I I I I' i Code 0 00.5 A 1.0 LPercent Total 0. 0 3.0 A uo - \1 _. 08 680- A 650F (est) 0.55% I5 I, I i Ii I 0. 1 1 10 100 1000 Time - hours 70 90 - O 6oC- -- -—, \ -.0 60 70 Code 0 0. 5 A 0.1 1.0 Percent Total 020 Deformation 1. 0% 30 - I, I 1 L 0. 40. 1 1 10 50 Defor100 1000mation 10 I Code s^ \ \' 03.0 800'F 0.1 1 10 50 100 1000 Time - hours Figure 4. - Stress Versus Time to Reach Indicated Total Deformation for C11OM at 650, 700 and 800F. 030o-0