THE UNIVERSITY OF MICHIGAN RESEARCH INSTITUTE -: ANN ARBOR, MICH. SEVENTH PROGRESS REPORT TO MATERIALS LABORATORY WRIGHT AIR DEVELOPMENT DIVISION ON STUDIES OF HEAT-RESISTANT ALLOYS by A. P. Coldren J. W. freeman Project 02760 Air Force Contract AF 33(616)-5466 Task No. 73512 December 30, 1959

Va. \ — V -

SUMMARY Progress is reported for research carried out under Air Force Contract No. AF 33(616)-5466 covering the period September 30, 1959 to December 30, 1959. It was established during this period that substructures (in "A" Nickel water quenched from 1800 ~F) resulting from creep alone can be completely delineated by the HI-3P04 etch-pitting technique only if the creep temperature is above 1500~F. Metallographic examinations indicated that creep tests at lower temperatures resulted in early, general precipitation that removed carbon from solid solution and thereby made it unavailable to decorate dis.ocatio:.s* artial substructure delineation was observed in longitudinal banded re ions in specimens crept at 1350~F. It was suggested that there was a smaller tendency for precipitation in these bands because of deviations from the mean chemical composition. Differences in chemical composition were also proposed to explain some apparent conflicts between the present work and other published data on the use of H3PO4 etch pitting to reveal sub-boundaries in "A"Nickel. During the period, an order was placed for double-electron-gunmelted pure niobium. A study will be made of the effect of hot working on the structure and properties of this refractory metal. Progress is reported on the adaptation of the rolling mill for hot working in an inert atmosphere,

INTRODUCTION This report, the Seventh Progress Report issued under Air Force;ontract AF 33(616)-5466, covers the period September 30, 1959 to December,0, 1959. The present research is a continuation of work previously initiated at the University of Michigan for the Materials Laboratory, Wright Air Development Division, on the relationship between microstructure and creeprupture properties in heat-resistant alloys. Specifically, the current studies deal with the influence of hot working on the structure and creep-rupture properties of materials having essentially single-phase structures. Special emphasis is being placed upon the evaluation of substructure and impurity effects in nickel. The creep-rupture properties of "A"Nickel were previously (Ref. 1) determined as a function of rolling conditions. Those data, suggested that the improvement in strength at 1100~F from rolling was due primarily to substructures plus any interaction there may have been between the substructures and impurity atoms. The present work is designed to test the accuracy of this hypothesis by (1) introducing measurable substructures into "A"Nickel and high-purity nickel under conditions that do not cause strain hardening of the type that broadens X-ray diffraction lines at high Bragg angles,and (2) determining the strength of these structures at 1100~F to see whether or not they approach the strength of the rolled bars. Information on the relative importance of impurities will be obtained by comparing the data from the "A"Nickel and the high-purity nickel. It was demonstrated in the Sixth Progress Report (Ref. 2) that by slow tensile straining at 1600 F, measurable substructures can be introduced into "A"Nickel. In the present report, it is demonstrated by an X-ray diffraction experiment that internal lattice strains are not introduced when substructures are formed by slow tensile straining at 1600~F. In the area of refractory metals research, it is planned to study the influence of hot working on the structure and properties of pure niobiumo During this work period, an order was placed for double-electron-gun-melted

niobium to be delivered in the form of 1-inch diameter round bars. Also, progress is reported on adaptation of the rolling mill to permit hot rolling in an inert atmosphere. WORK DONE DURING PERIOD During the period, further studies were carried out to develop suitable tests of the role of substructures in hot-worked "A"Nickel. The procurement of high-purity nickel and niobium was advanced. Construction of the atmosphere chamber for the rolling mill was also carried along. Substructure and impurity Effects in Nickel Substructures in "A"Nickel In the Fifth Progress Report (Ref. 3), it was reported that there appeared to be sufficient precipitation of carbon during air cooling of "Al Nickel from 1800~F to prevent it from suitably decorating the dislocations so that etch pits could develop and outline the sub-boundaries. At least this appeared to be the reason why substructures could not be revealed after creep at 1100~F in air-cooled specimens or in specimens rolled below 1500~F. Microstructural evidence indicated that the precipitation could be suppressed by water quenching. Accordingly, a creep test was conducted on a sample water quenched from 1800~F using a test temperature of 1100~F and a stress of 11, 000 psi. When examined after 4. 1 percent creep, there was no visible substructure and a considerable amount of general precipitation as shown in Figure la. Presumably, sufficient precipitation took place before the substructure was formed to prevent decoration. This is suggested by the fact that specimens prestrained by slow tensile deformation at 1600~F to develop a well-defined substructure were shown in the Sixth Progress Report (Ref. 2) to retain delineation of the substructure during creep testing. This result suggested that the lowest temperature for creep testing which would result in a measurable. substructure ought to be established. A 2

test at 1350~F under 5, 250 psi with 1. 42 percent creep resulted in banded areas of precipitation and visible sub-boundaries (Fig. lb). A test at 1500~F under 3, 325 psi with 3. 48 percent deformation gave a well-delineated substructure, although there was still some precipitation (Fig. lc shows area of complete delineation). Further tests were then undertaken at 1550~F. No evidence of precipitation was found. Three tests were conducted at a stress of 3, 000 psi to creep strains of 0. 56, 1.91, and 3. 53 percent (in 1, 5. 1, and 22 5 hours, respectively). The substructure was rather well developed after 1. 91 and 3. 53 percent deformation. The number of small subgrains appeared to increase up to 3. 53 percent deformation without much change in size. The specimens tested at the higher temperatures and larger deformations were subject to extensive intergranular cracking at the surface, In those tested at 1550~F, there was very little cracking when the creep was limited to 0, 56 percent. The two larger deformations exhibited about 40 cracks per inch, averaging 0o 0018 inch in depth with cracks as deep as 0. 005 inch. The surface layers were also depleted in decorator atoms so that the substructure would not etch in these areas. These results indicate that measurable substructures can be produced either by slow tensile straining (Ref. 2) or by creep above 1500~F. The use of creep for this purpose would require that the surface by protected against reaction with air; or that large specimens be used which could be remachined to remove cracks and the decarburized surface metal. The conditions under which measurable substructures can be produced have been surveyed. Pre-induced substructures require slow straining at temperatures above 1500~F to permit a very high degree of polygonization. In so doing, however, there are problems arising from surface cracking and surface decarburization. The cracking introduces an uncertainty into the stress calculation, and the decarburization prevents the formation of etch pits to delineate the substructure. The possibilities of deriving a series of 3

samples produced by hot straining which can be used to determine the role of hot working in increasing strength are being evaluated. One of the questions concerned with the evaluation of pre-induced substructures under creep conditions is the role of internal strain which may be present from cold work. In the experiments, it is desirable to separate the two effects. The well-defined, nearly equiaxed substructures associated with slow tensile straining at 1600~F described in the Sixth Progress Report (R ef. 2) indicated that there might be very little cold work present. This was verified by comparing the width of the X-ray diffraction line from the 420 reflection for a sample deformed 19. 7 percent at 1600~F at a rate of 30 percent per hour with that of an annealed specimen. The line widths were equal as shown by the microphotometer traces in Figure 2. This indicated that samples prepared in this manner would reflect the role of substructure (plus impurities) alone. Considerable effort was expended in attempts to understand the results in view of possible discrepancies with published information in the literature. The limited delineation of substructures in the samples being studied in comparison to published data is particularly puzzling. The "A" Nickel being used is rather high in carbon (0. 06 percent) and in other trace elements as well in comparison to other investigatorst "A"Nickel. Guard for instance (Ref. 4) used "A"Nickel with 0. 015 percent carbon. It has been noted (Ref. 3) that when precipitates form, it is not possible to obtain proper etch pitting with H3PO4o Apparently, the larger amounts of contaminants in the material used for this investigation has intensified this problem. Guard's photomicrographs, for instance, indicated a depleted zone along grain boundaries which would not etch when grain boundary precipitates did form. There is a good possibility that the fewer impurities in his material was responsible for the better delineation of substructures in Guard's work because of a smaller tendency for overt precipitation. It should also be recognized that this investigation has the objective of studying substructures as established by hot deformation. Other 4

investigators have been concerned with structures derived from cold work plus polygonization heat treatments or those developed by creep alone. The problems of delineating structures developed by hot deformation may be quite difficult. Further work will consist of utilizing the known.conditions of delineating substructures and utilizing these to define the role of substructures in creep-rupture as developed by hot working. High-Purity Nickel The initial attempts to deoxidize carbonyl nickel powder with magnesium to produce a relatively pure nickel ingot were unsuccessful due to the violent vaporization of magnesium. The procedures used were reviewed with the individuals who had recommended the method. No obvious differences in procedure were determined. Several suggested modifications did not solve the problem. At present, the procedure is being studied for a way to avoid the difficulty. REFRACTORY METAL (NIOBIUM) An order was placed with the Mallory-Sharon Metals Corporation for 25 pounds of double-electron-gun-melted niobium. The stock is to be supplied as 1-inch diameter annealed bar stock. The material is to be produced to a Brinell hardness less than 85. Typical chemical composition was stated to be: 170-270 ppm of oxygen, 35-100 ppm of nitrogen, and 100-155 ppm of carbon. Fabrication is to consist of machining the surface of a 3-inch diameter ingot, forging from argon at 2000~F to 1. 25-inch diameter, and rolling to 1-inch round. The round bar is to be conditioned by sand blasting and pickling. It will be cut into 10-inch lengths and vacuum annealed. The order was placed with Mallory-Sharon on the basis that they could provide the size bar needed in a reasonable time. Other sources required the acceptance of a large-diameter ingot or a prolonged delivery time for making the bar stock. The cost between the different sources did I;

not vary appreciably. Modification of Roiling Mill for Inert-Atmosphere Rolling The chamber sealing the rolls is nearly completed. It is expected that it will be possible to make the first trials with the mill early in January, 1960. First trials will utilize a Hoskins Alloy 875 resistance wound furnace capable of operating up to 2200~F. After extensive checking of possible furnaces for very high temperatures, the choice of a graphite resistor tube furnace seemed most practical. Accordingly, as cleared with the WADD early in this reporting period, a tube furnace having an inside diameter of 4 inches and a total heated length of 24 inches was ordered from the Hevi-Duty Electric Company. This furnace is designed to have a relatively uniform hot zone over the center 12 inches of its length and will be capable of temperatures up to 4000~F with the 40KW saturable reactor control system to be provided. This will provide stepless control over the entire temperature range of the furnace. A combination water-jacketed cooling chamber and purge chamber will be provided at one end to provide a means for loading and removing bars from the furnace The other end of the furnace will be attached to the chamber around the rollir millo Pieces up to about 2-1/2 inches in diameter and 12 inches long can be accommodated by the furnace. Delivery of the graphite furnace is anticipatec in February, 1960.

REFERENCES 1. A. P. Coldren, J. E. White, R. K. Bowen, and Jo W. Freeman, "Studies of Heat-Resistant Alloys", Proposed Wright Air Development Center Technical Report 59-606(1959). 2. A. P. Coldren and J. W. Freeman, "Studies of Heat-Resistant Alloys", Sixth Progress Report to Wright Air Development Division Under Contract No. AF 33(616)-5466, (September, 1959). 3. A. P. Coldren and J. W. Freeman, "Studies of Heat-Resistant Alloys", Fifth Progress Report to Wright Air Development Division Under Contract No. AF 33(616)-5466 (June 30, 1959). 4. R. W. Guard, "The Role of Polygonization in Creep", Preprint Copy of WADC Technical Report Covering Work Done for Aeronautical Research Laboratory Under Contract No. AF 33(616)3263, Appendix A (December, 1959).

(a) 4. 1% Creep Strain in 166 Hours at 1100~F and 11,000 psi. X1000. (b) 6. 3% Creep Strain in 45 Hours at 1350~F and 5, 250 psi. X500. (c) 3. 5% Creep Strain in 20 Hours at 1500~F and 3, 325 psi. X250. Figure 1. "A"Nickel Water Quenched from 1800~F Followed by Creep at (a) 1100~F, (b) 1350~F, and (c) 1500~F. Etched electrolytically in 40/% IPO4.

__,___ I __- -: -,,-. I --- - - I;i-I.iI. — -I-I..I;,, -IIII iII7_i -1 1. I i i — I..1.__; — --, - __.- - -,. — I, , ,,-,-,I.-a. -. I, -o_.1.. -.I.I I.-- - -., t.. -- I.- -I- -I.-... -:.I —.II..III -.. —;_-_II1"_., —1.iI i.I_.I. --., —i -i ---! ---: _" ---.,__II;I__ ---"I-..,. — -.-, -+, ----,.. -1 7 I.-. -, _; ,.1.,.I-.-. -f I - _. -. -" —. — -..., - '. -.,-.-: —. -Ii- -1.-1:., __l7'' —..I..,,;-- '7 -- — r 4- ',, -ILI. —..,,-.,-,,_ -.. — -_..-_.-I.!,. --- - _ —,-. —,. -, , _-.,i — :,I.I.;I:. __ -:., _.-,,.- I.-4.,- -, -- - -,-..7-T-_j —i- 14 —jI, - -_.." -.,II"-,,..... --—. I.,-, — -, - -, —,,-. I- I I._'.. __;__I" +-1 . I,-, -1 ", -,-11. - I — -,; I- - -... - I -.11 -...., -.1 -I -; 1 —l.- 1, 1. 11 - -4! —IIIIi-I.- ---,..-1,11.., .,.,_. - I.I,,-.II-..-.,,I -,:.,-It 1. I.I+II.-.,,I,;_r "-I,--t -- -,, -_ —. - —., -— It__.-"-I,..,_ —.,,,4 '. -,7.,-...-;- —. -1,-.i-;_..-. o_: _.. —;..,:,- t- __ —,.. -4 —! — - -— I _,,I — -,I-,__!L -; —, —..I I... -— t -— I:,..I_:I. ----.1 - __j_--, _! r-I -, -1:-4- -,,,-; -.+_ ,- I -,,, _, - I,-I.:.-II_.. '.. "... ,- -.1.?-,-.I-.4!.L.t:,.IIt..II.I —, -t -.-_ 1_71 OT *II.IiI..I,. I..iLLT, — - - I:,"-.I iI.II-i.- -_ItI:,1.T i.I..It:I 1:7 4._' - II- -.-III.IIII;IIII1-'I-I I.I.1, — il.. —.".,. I -....- I.....I.- ".,-77.IIIII._. 4 -,.,- -, - - - "I" — i -: -, -,- - __ t,.:,,,..'... -_,-.11,II -: I- -, -- _!III_,,., ;_ - 'I,'I,,.,L -, — -. -, - -.-:,I... - -— I,,__:1 -, —I _'_ .II.I.II.-4 —I-,-t-.-,. I, _?_ -_-.1 -,1_4 -!. -1 I- I -_14 I _r.-..il-,- -I.1. '. III;1..-I -,,,_..- - --—,, —.--4;,. I:,- I-1 -!. I..... II _.,,..,.,_I___;__rll__-_._l. - (1. ?: " -' -, .- . --- - -. -, - -, - -.,-:_1 I-. _.-'. t _- ,.. -.I-+.. I. - '' _,_ - _.__ _-11. -.-. , .,.-I ''. ;-! —,., -v — i 4- - --4_: -fI-t- -,,- :,,;...:i-,I rI —. 7 -- — - 1-t, -1-.I -- -1-f-1 T -I-. -.0+ —,-,,-, —;-.1-.I.1!I.II._. -,.11-1 ----I — -- -, -f-t Ir...., —,,-.1-...... -..-, -,. —:I,,,I..I.i,,-.- -I __ - - -- - _t__-I.-.,,. .14-__.1.;_-.. —I,-_L-... -;-. -i.I-,-IT -,_..;:Ir; —_-l-__. -.I —,..-II... -...-.,_.,.1 t-I-, --.1-1- 1. I-,_ t — I.1 1-1I..I- -; ---, --- -;. - — I I.......kI '..,,,,- - -- - - - — -II. I.I-.1.. -d f 7; ". I+ I- 4- 1 I- -, —- tII;I Ii_1-4 —i- - --—.I. 1. —..I,, I..: -4.-1 —!.-.. —II. i..-..,,. 4_.I IP::,.?II;...I.IIi III-_rT__I ---, —.I-!..I.1:;!q..I. I;i, —?..4-I.,.,1i4-1 -Ir —,-I- ---I;I..I- ---— !ji--.I,,;_;!-_ -.-T- - -,1.I,,-.I-_..+. -I... --- 1 t - - - - —! _ " i +_ -1. 4- - 4 I- I.,; It_,__l__ - _ - I 1. _7 __ I '' _ I,__ - -:. ...-I....-..-. - -I I - 11-,.; . — -- -III.-t-,. I -_...-. -t..,,- J, —,_".-, —.+ -I..T. — —I — -I,-,,7 ---, -,1. — -.'III__-._...j. -; —4- 1 --- _ f _. -4 _-.1 4 --- .4. L- - -,,.I.-..,-_ __4iI11I,I'...I,.m___ t,_ —,:,.- __-,,,:__tI"I.r ---_. , --___ — I --.I,.1...I., —, _. __!..:- ---------...I- II..1., -.-;I14IIi IT.I- _,-.-II —I;_!-, T —,--,AL -,,,.-_j.,-, I I- —, ---I.I-', 7-7 — - -r- _. —1 —.._.. T;.-, 1.III,,,".. -1 i,I___,_,_.,_ I-I -, _1 _: — i.II. V .I, — I -- -i - -!:,II;,,' — — I- -I ,.I-TI.,-I -I'-,- 1-_,,-,-I' — -,.-,. —t_ 4-1 — - " I.. II.. _ __ .i. II- i- _! IT -, —I-,-.. ---,.. -..I, -—..--..-t-i.-II,.I — '..:II-.- ,I.,II; fI,.ilr,. -, —,.;.I ---.-I —..I,;-: — -1-7j:. I: I-, --- -7 —.-._, I.I.I.... - -! —..-:-, -— IiI — —I+- -,,I__ H,_o-.. - — TI-,1...1 1.-,,III..:,1. -! -;-,.-11., ,; - -... I., T-. — f —, —i,.7 —:t-,-1I.I... -— I_;__.I-II 1-,-__,__-..jI.IIIII. _i I-, Iii- 1 --.,.:7- '"I,:i:,Ii;,.IrIII.I.11I.II. IIiII. ---I:-I. --- -- I-!II,..." -1..I..II I. I. - I. ---.-_III!I.i.I ,i__ -o - - 11 -.. I:,IIfI ---- I. -- __ I - L_- i ----" -,- + — — I -I- ' — 4-I__.I.. -.-;;- -.- — II.. - -.,I I-;II,, —I1 —_.'II__._I- -.. -,. -.- -__ -1 I..-Ii -.. —,liI:.I-.I:IIfT `7 -- - -r — ,- ---- - J- 4' - - -,I.II.-1,.-II,,I-.-... "__ -I.4-':-, -,:-,;, I;.1.I.II- I -, -._1 — ---iI..I" _--_'__ -- i. ----- --- -,.-,,,.!-. 1-i-4I -',!-1. 1. I,...,-II_,4.-. — — -,_i..,.+.- -I-.;' .I-I-,I!- -, --- —- — ._ ., —. — -—, — - -LL ---,., ---'.-:_ j "I' -I.- — .-I- -_-4I.i..I!I --- II- _- --- 11 -__ -I. —.-. —.-I.-.I 14 ,.I.,. -_j -, - JL-,-. _...,,.,-.;7"_:....I., -,-.?," —:.I I.II7!i-.., -__. ---- I-,I. -.__I__Ii-. -,-_-....,,_ -— -+,, -, -,t-I-IIIiI..,-"-1III.. --- -- _.-. -I -- -.-,.II1. _i.._.__ __ - __, -,..I- --- -.pI.:1I,,-.-,_- __ -...-_ -__ L,. -,-I ---f,-__!I.I. -,!,- -—.- I --- -7.-.__ -.4-,.. I!+,I,..1 1- - _ II.-.-, —z It- —I1 -: —, t T- - -, 7 -, - --—. -,.I-1., .., I 11 - — I-T-,_, __; _ — I', -.....-._ —I...-:_.,,I !11 - I,-!, -,,,-Ii:-,-.;-] I-,-.-si i iLi, 4, -4, -i v; 4-;:'q-_l" - _"..IAI.II.-...,IIm7,i-I,.III-.:7.j'I ---- — I.:TII ---,v-IIIIIII-iII- __ - - -.. — WK - i,:.-; -—..,-:-,IW..r - -.IqI-II-,; __ - — t 4 -,, -4- __, _.II_'..-I - - -.-.-- +II, '. —. I- -, — -f -I -, --. t.1 —1- A-',;-I 11j....-,. __-,,,_ -;! - -, — ,!,-, - -,.... ',. — -- --— A, 5-.74Ir -,,. -4- -—, I -. " - i _. - . -,.,...i...II1,..,I-,.:. I_ 4-,-,-I..- I-...II...:I, - __.-4 - ----- ---4- - t- 1... -.,?. -1 _.- -, _- .1- ___M -, — _ L-;". I. t_ ":. — -,.... -...-... III -. I,.I-I-_ . 1-i- - -'_,!,-, -I.I I T-,-.. --,,-..-..I 4,__, __.' -,_ I! -,.-II.., I-1,_! __ 4 ---- -" -- -,- 41,,-I,- I__., ,,...0 —,I-"-l_ .;-r __;_.,,i+ __ __ I _+ I - - -I.A-f.-..-,-. ---, 1.___.. I —.. -.__ "et. - ___..!II: J.,.!- -- -...-,-,,. _:.. -,.- -,. —,,.,I-.i —.I I.I14 ---;.. -. — - --,-. J I. 14! I.. __. - - d- -.. -I-2iII.I.IjiIIoaZ4 , -' _ _.:11-1 t-:,I. I! -i-.34 - I,_.:,; -! I.I _4_I-_4-1 _____ — __. ---,I,!-IShi to 11T1.I _;,, 1,I,'al-_-.I- - ,!,I:-4_,__j__t__ 4, _ lf, A-r,.'-At-3I. -—,-,.-.___ -.1. i ,Ii' -i 1-:1Ii liI — T- __ I.- II- — -;;I:III--7 -,.--,-.i. — t -,r —.-. - - — L __ -1I- —,,M._ -- - -,-,. -1-.II._:_ I-:.II.- T.I.IIIi.,,3i -i, -, —... __-.-,-,.-. - I.- -I-"..:. I_',.-.1.1.-I I..,:I I.f_' -,II,I..I -- '.;- --- 4;,'..-7 '-'''-'-,- t- -, —, -- --,- _r II- __ I- - -I:_ - -.I- . -I 1-.IV-_- _'_ -1 — L I.- 11-i -.--__;_, -I,.-.1 -,,T,, "I -` I —L — 1..,. -T.,___Il -Z.,,-1I.`_ - -,,, --,,,_.-.,- - -,I,. I: _.....'..t..-I.-, 4,!,.,. — IIIII __ - ..-I,:..., —1, __.,..,-.,I-.. — 1I1. I -.1, —".;_ -1-i —t - - .. —., -_ -,-i..,, -1!.-,:.-.. . -' —:, ---__,___ _.HI-.- — _-_ ".__-"II.I... --.!!!,:_, `- - -,I I — L -iT.,4, —,- -f-. -.I-_ I. --- -,, -1 I 7,-1-t- I-,I L '. - -,,I- 4-i-1,..I,,_ ..t -T-. — 1. I,,I-.,1-i;IT-.I ---T-I,,",-.I... -7 -..-1,4-1,.- - - ,-.,,-.-'.. —:.t,-_ -1 4 1.I,,- 71 tT!...,-, -,-..-,. I.-,L-.,-,- , _71. 11,, —. -No!_7:-I,-,.,..l..__;;.-I -4-,_. -I —,I_ - -,;1. -.,,,,1-1.;,q1__ -i.I I. -...1.j_, - .-.1 - I,:,,- - -, ' —,17-;. -I, —, ` --,I,.- r-,:-.,: - --— I I- - --. —" - -1 -- -, -, -4- -— 4-+-. 1-.- I -- i--'., "I -1... __. III:...I.,I!II —,'i.-7! -I.i -, ---.., -_jt.:_ f, '-.r - _ _- -4.,-,,__-,tIfLiI.I.iI-.III,.r II I,I q-..I.... —I;..I I -,,, —I.. -r-T- -- "I- I4_ li. -.I-1 _ 4' -.'-, - - -J -4-L, -t-, __ 1-f-Z — _ -,-...I — 4 4- __f1, ". _..-, .;I -I; ---.._.-lt.__Tll..", __,.. -_ -.. I - I- _,.".,,..II 4 —::. - --.,-, _. _.. -L-.1-...+, v-, — '.I- -Iq- —! 71..I..,- —,, -,,__ `- ---- 4 — 1., -T -7. II -,;.;,-;I-_:_- 'Ll-I ---, — -t,-4- _ T.,.4 ---. It,, i-T-,.-I;.-,..., — +-I-. -.1..I,.-I -. - -,,.. -I..,I —. j-,"L — . ---.11 - -;- _- I, L. j. - — '..i -1- -1iI li -_ -1 —i- I - ,, I -,- '!I I -.- , I. .I.. i;-+,._ -4 + —,. - i _4,! - +..I- -,..- - ..,I,,,iI!I;.I.III I —... — -- I- _;I._. __I"., -, ----II.;I..I... —!I -,_ I.-..4p-I —.- -_ __ r.- _1 I_ -1.. _t. __- —.-a -..-.,...,.-....."_, 4i4 -,- -"'..,I — -,,- -,-. — -I -.- _ 4 --I, -,i,-..1-11 t. .__..1.-1 -,-,.- 4_ I-j-! -. — ., ___ -..,I,I.7 - - --—.. -,,, -.....- - ---..I- " -,-,T- I. ";.-T ----I : -— t-+ — I ---..4.. -. ---." -, —,-1. I.. — -, __, -...__ I.;..-.. -,...I -,:tL, '_If -- -- I- -4-1-1-,I,- -J — 7 —I-. —,-, 4- -, II,.III -—,I. 4iI ' _: — +..,-.,.;Ii.-+"-. - -,:.-I I;.!,,.F,I.IIIIII —.,- T-. -, - —.:_ '... -...6.i.,,.,!It-IjIII;..IIII.I.iI.I;_.II,,- -- -1. —..-I..l..-. _. _-,III;I!1 --- -,- -,-II..-,I:i,7 "TI- -- __ -- I,;:-..II — I.- -,- — j. -- -1,... -I_ —.11 _. I._-,-,, _,_.I.-I _! ' —__'41t- - r..- - -,,.,,, --....1-, '. —.,,I —,-._; -i- __ __ -4 --.-.I II I-.- - --,.I- -.1-1 I.,,-::... '...,,,. -. —; .-1 _. -i.17,i.il _6 _i-I.I,.-,,-,T'.IIII, - -—;,Z, -.. I.I. I,__.. -_,- -1 4 "L7, _-..-T, -'-.. .7 -!.".-.1.I.I-.,I;I.I..III-!:-, - -+.-.- L - _,.I - —, —....T,1 —4- - - -- -I —,- I;I,.I.I...IT- -,, 1 -__ --—. I- I, - 1I.......-..-.:..,,!, i I... — __,i,;- --- ____, -,:,, -- ---— _-!, -,.I-: " -.. —_- -,- - I..71; —t-.,. —,-,.i- -1-1-1;..,- - f.'.:_,.- I._; —__.Ii,-.,_ -, -—,4- -.4 J","t,::711r'i I-, —i-. I-,- -1I- I It- _,__r_-,, I.-.1- _, ---4- -, —_...::II.-1iI. —,. -. —.-., ": ----— i.1..'.t._. .4-4.I-;- m — - -I- --—!14.,..__..: -;.,.,I-4.,.,-,- -,.-1.11. 0I,,II:_,-I.I.I- —II- :-I.-:: _'...,-1 —,_.-. d_ — t! - -- ------ I-.- —.t-.IIIiI,,.,. —,. -, , —T 4__ -,-f':-I. --- -__ —jI.II,, -.-,-, rt. - I..h.,_. --- —,-,. -! —, -, -4 ""-t -..-.. __IIqII-.. —__-.; - -- _;, __T.__I,-II.I i;1,4i,!7 II-' — -' -T.II:. .i. _!, _.I.I,I,.II;I I.'. __-,.-.I- I..: t- -- —,tI-, I- -,,_-_,- I-,-.-,..!. -- 1-_7 1. — -, — - _ -— r.- -;II.-I.;-,;,,,. —.__ — 1-II.;,.....''.., -,. - iI.- -..-!--_ -.;.. -_ ._ -11 AI —,-,,.,I _1 -.. -:i I F_..1,-__.,._l.-1_ -.- - 7 -.TT, __ _,:",I...,.(T.-. __T. ---! -t - - -,,. r. ----.:IIi" -T',-:. I....,, I;,...-.4- . II I.. :-: I '. -.-++-...I ----1- -fI-..,.-,, I, I-i. -.; !,-. —i — __... - - I - t —__,_.7.. "..,,11.-,-1..I — '. -,..; -4-.,,f, ""I.!I1,!,II..,I;:. I -7.._-;_,! -.,..- 7- -. I.-.. I. I...- -TIIti, —.- - -.-... _,,, __;,;_ -...+ — _- —,.- - -.. 1 4__ —0 -q1- - r- __.I._.-,, - - 1-., - -.i.I.- —..., — -i,, -7'PU-.___. -!,.:,II:-.,.-;!17-I., -:-,1.II-4j. I;IIl —. ----4 — L;,,,.;_IIt-f.."- I, __ - - - - - I - - -"-1 I -II-I. —4 - ''' —I...-.Ii- —,.-..;..I; GQ.!J.:. I.13I :,-.-... oIi.- ___l ---:4''.II.I, 11:" IIII I ...-, -I -.; -jIII..- I' 11 -. --- -, - ---- -,- -—. --- t,.I-I._I.iIIII,-'T-;: - TT T!!__I;I; —- -, -,-,-II-_1_7;I II,.I..IIf ----:`. -I.,-.,I-I.11I.IIII -I;4.I,.-, _; 4 — - 1, r -.-,.., .!. - v -. ._ --- I_. .-II_-;- - -I;. W-..-, "I -i — —, — I..+ -... I — L.4. ---.,_ W..-.-._j.1 - -+_..,..- —:-,;-.1.-.I ---II I: ---- _. ---.-I.I.. Ii...,a I;. i -. -__.. _.. 4.__ -....1''-,-, " I;III II-,I., I _'i.- _. _+ _l -,.I!,I-"t,-,::,,I.-I —.'.. '- -r- -- T- ''T__.- _', -.I.I,-.-,-...IIq;..1.7 -.-III II-:-1-. 7t -.,,. I.,-...1. -._.I.- -1,j-!-4...I--, -;_ - .!--tI.. --- -. I.I —_,-, 411....II,Ii.. I.: — I —1 — '-t, --.7.. - 4 -!I.:'. -., -...-1. —II I,1. I . — _,-_ -,-.... -,,-; — 1.;_.... ,_ -..IL., _. -,,_ _- - I:.,.I —:,_t-t7;I,.II.:,,:,-: -1III.I 7 1_4.;., -,, —i..,I_...I — II.. I ,"I,Z,.=.-.-, -.- _,; - -;_._I — -,I"II.,f-,-:_;_ -:. i..-. — - —..., 4,,,-, i--II ._-,III.., -,, a, WI_,,,.!I-I - i:h.III. —II.Ix,.IiqI -,-Ay,-,I:I.-.. I, -I!I-t ---- ---, ` __ -I I__-.:,. -_..IiIi —T-.;IIII.,!0, "*_,..- --. - —, ! I.iI —i t — : ;;; i.I.1... - -II!,,.-... _ ---- -1 I -I;-...I.I.-;,__ -;,.T —.. - -- -1. +I -.. 11I; ----,,-_: -. --- I...I.-1 1...41 —.I...I- -II:,_:;-, - __ -!.!- - I..- _-, —I.,. I-.-. _-I-... I.; ;-_tI,-;I 111 - -I,-,.I —. I -, 117-" -1 -.. I- .I-,-1- .:,_ __._,, _ _;-_.II... — -5t. p __I -, jw!, _P_ 141#_ -..'' :-.-,: II I.. II._:, I. - -t -.,__ _..,.,_.___f, — —,_-__IIII;.!qI.I, ",_.., . --1-i 4.I... 11. I-1.I_;II ..-...i — I. - ...I.;.!-7 -:, 1. ___Pv-.1!...II.I.-,.....II -,I-.7I.I 4.,-1,.. 1-177. I -1 -..1,_ _L.., -- I ,__..I--. — -— "-,-,!I-1 '_ I -7 Im+.I:II;I....,__,,-1,:-I,.I,, I. I,-, - -, T- -t-q,,,. -rI .-.. —.,.. -A -..- _..I.-F. -:,_ _ —..-..I ,4 -...,:.-. -L.. -— I.._ —...1... - I,__,.I._t,,.i., — I-,.-:",,., +-:_ --- -17 --- I;- +,-71..- -", ---!, —,-,,,7,:,,,, -t:I --- -'fixIIII,:.--4 1 -, i- - —,,-4- -4. _,L I..1 --.g::_ -_""_ ',.I.-,4-.f-T 'I,,-11II:. --— i —FI,I., ----1-. —I.:-:II- -, -L-;I.t4 t L-__ -11. ---.I__III;I.I I _,_ 11 , -. - mo-. )..,u File,, I I I -;-. I- I.II. [- i I.1II:rI.-, -_ -+....,. -1, -1. _. 4 - -..-. - -- -.. a.-_I-' i+__ _-_,,.... I- -— 4,-, - I.,..;II I.4.II II.! —-,.,_. — i-.-,-_ IT. _e-..I.I.1.11I,!,-,.,..;-.__ 1.;.i.II-. --,L __ ` 7''I.. — -.1I!,II!:4,.I!'__ T" - -;.1..m_-,..,.;, II-__ m II I __! ---— I11 Io1...I -.-I,.17, 1., _11_ -pd - - t ,..;I. — - —Iil,.I-.,-.. I 1. - -1 __.,.. .;,- - -, — - - -'. I ----I — 6_ —,- t- —.11... -- - I I.- -!:,:_....__ __..:-.. I..-..,I. II I..-1 -!-..-.-.! --- —,.... ". _,_.,__ -i i-.-". ._' , -,.-!.-!.-. .. — -I.. I. - I- ". -. -- - -...1. -. 11 1..... —..I.. I,.,-... —; _,-!. -, —. __-i -, —...., - —.-. _... -. I,I- -—;.p-O... -. --.- L ---."I.,;,,,,,,:-, —,, +t..-' - -1 1, —I..:,!- -:,-,-:-,, -,-t-I-;.-,-.-__. I,I I - - -LiI -II- -__ -1-..I'I -14,.- - -:,II! f:. I-I'.-.I _'_ ---- 7- '-- - I.- -mI —.- -,;,,-,-,,,,,,- -'_ -.1 1.iI, -tt i 41..__I1;.. I — __....I.... —-__I.T.II.,Ip.IIi...;I7,I ZoIo_.:.I — —.,-,I.1t, —. -" - _i- ,. Im -1-_".,.- 11,4 —,-.I-.-:1 __ - -__ .,-... ---.. -.. —.- - 1. _I I.-1-f - -; — ---— I - --.-1- -!..I-.,.-.,__ -I — 1 -.I.j __.-III -,,...-. —,WII Au- I — 1-T:__1 ---,,,- -.-.II-.I- _,L_, _,,,..-.I.... . ol —.... _.. —.I..- I _.. -. -—..,-4---I- 1 I-,..- - -I —A --4 ---,I",-.-..II.II..i ---,-, —, r- _ -.-I -,.-.. _L_ - -fq __,. —! -.-I. - 1. 1.....!_-1 — "!_,I:_ _. I -,.4. -_.IIII__I"+-,", j_-,-,.-II_.1,,I.,,:..I I....,I-1..I.!,- - .,I-I-.. __ —__, —.-..:_i,0-;fbIt*4,r__ ,.t,- I'. _.., ".I:_. -..:_ -t I I I-.- —I.I..__ i. 1, --- — T:1";!'t-, — -1,.4..,_.I I..-, --..,t:-_ ; I I... ---'T 4- I1.,.-'-t-,,__,.t 7 ~r5t it [,'~.I.~_,,i i!" ~..7.i rl 2- - -~1 -:-'ir — ".r t + j-?:! '- + -'~ — + -?t r --. '__ ~-,- -,~ r-; I;:;,-. -. i 1 -r-1 t'- *-;t +" t-' ' i.,!;:1:. - t~, 4 _ -:'? 55 —; -e i.i - t_!{i:- 1 t * |

DISTRIBUTION LIST Contract AF 33(616)-5466 Hqs, USAF DCS/De ve lopment Directorate of Research and Development Washington 25, D.C. Attn: Col. John V. Hearn, Jr., AFDRD-OR Chief, Office of Naval Research Washington 25, D.C. Attn: Mr. Jo J. Harwood Metallurgy Branch NASA, Lewis Research Center 21000 Brookpark Road Cleveland, Ohio Attn: Mr. G. M. Ault Allegheny Ludlum Steel Corporation Research Laboratory Watervliet, New York Attn: Mr. W. Wo Dyrkacz Battelle Memorial Institute Department of Metallurgy 505 King Avenue Columbus 1, Ohio Attn: Mr. J. Ho Jackson, Document Librarian Battelle Memorial Institute Department of Metallurgy 505 King Avenue Columbus 1, Ohio Attn: Dro R. I. Jaffee Climax Molybdenum Company 14410 Woodrow Wilson Avenue Detroit 3, Michigan Attn: Mr. A. J. Herzig Curtiss-Wright Corporation Wright Aeronautical Division Woodridge, New Jersey Attn: Mr. A. Slacht General Electric Company Aircraft Gas Turbine Division Cincinnati 15, Ohio Attn: Lo Po Jahnke, Materials Laboratory General Electric Company Aircraft Gas Turbine Division Small Aircraft Engine Department 1000 Western Avenue West Lynn 3, Massachusetts Attn: W. L. Badger General Electric Company Research -Laboratories Technical Library Schenectady, New York General Motors Corporation Allison Division Indianapolis, Indiana Attn: Mr. D, K. Hanick, Chief Metallurgist General Motors Research Center Detroit, Michigan Attn: Mr. R, Fo Thomson, Head, Metallurgy Department General Tire and Rubber Company Aircraft Sales Department 4 South Main Street Dayton, Ohio Attno Mr. Ro E. Stork, District Manager International Nickel Company 67 Wall Street New York 5, New York Attn: Mr. Mo P. Buck Massachusetts Institute of Technology Metallurgy Department Cambridge 59, Massachusetts Attn: Dr. N. J. Grant

DISTRIBUTION LIST (Concluded) Oak Ridge National Laboratory Metallurgy Division P. 0. Box P Oak Ridge, Tennessee Attno Mr. Wo D. Manly Universal Cyclops Steel Corporation Research Laboratory Bridgeville, Pennsylvania Attn: Dr. C. To Evans, Jr. Westinghouse Electric Corporation Ltion and Gas Turbine Division,as City, Missouri L: Mr. D. C. Goldberg American Brake Shoe Company Research Center Mahwah, New Jersey Attn R. Jo Ely Manufacturing Laboratories, Inco 249 Fifth Street Cambridge 42, Massachusetts Attn: Mr. Bo So Lement Materials Research Corporation 47 Buena Vista Avenue Yonkers, New York Attn: Dr. M. Ao Adams

UNIVERSITY OF MICHIGAN 3 9015 02841 2891