AD-A26 2 924 ()

EW-23-92The Effect of Temperature on the Impact

Behavior of TiB 2 Reinforced XI)TM-Ti Al

Intermetallic Matrix Composites

M.K. Hamm and D. F. llasson

DTIC

AR3 1993

LT, USNRIProfessor

Department of Mechanical Engi neringUJnitcd States Naval Academy

Reproduced From

Best Available Copy

93 4 12 046 93-07612-- -- - - -- - l~ /ll /l•]l///t/l, \

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RLAlI INSTidJC11iUN5REPORT DOCUMENTATION PAGE f .til" 1,01,imI. REPORT NUMBER .. OvT ACCESSION NO. 3. RECIPIENT'S CAT .ALO.G Hultr

i! EW-23-92

4, TITLE (and Sublitte) . y'yPc OF IEI.OHT a P4t.lo COVt NEG

THE EFFECT OF TEMPERATURE ON TUE IMPACT BEHAVIOROF TiB2 REINFORCED XDTM TIA! INTERMETALLIC MATRIX

6. PERFOR•IN G ONG. NLPomy humst5tt4

COMPOSITES7. AUTHoAfs) S. . OV"TRACT OR GRANT NUh 'BER(. .

M. K. HAMM AND D. F. HASSONN0001493WR24019

9. PERFORMING OkGANIZATION NAME AND ADDRESS 10, PROGRAM EL-EMENT. PRO.)ECT, T ASK

UNITED STATES NAVAL ACADEMY AREA & WORK UNIT .MU.. HS

DIVISION OF ENGINEERING AND WEAPONSMECHANICAL ENGINEERING DEPARTMENT

It. CONTROLLING OFFICE NAME AND ADDRESS 11, REPORT DATE

UNITED STATES NAVAL ACADEMY NOVEMBER 1992ANNAPOLIS, MD 21402-5042 '1N HUMUIE1 OF PAGE

IR14. MONiTORING AGENCY NAME 6 AOORESS(it ditf.,.,n from Controlling o0f114) 1s. SECURITY CLASS, (of this report)

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SCHEDULE

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I?. DISTRIBUTION STATEMENT (ot the abstract entered In Black 20. it dill.arnt (rom Report)

I&. SUPPLEMENTARY NOTES

It. KEY WORDS (Continu, on rvers side It , ." c.. eary and Identli- , by block number)

Intermetallic Matrix Composite, TiB2 Reinforced, XD - TiAl, Near Gamma

Aluminide, Instrumented Impact Testing, Notch Impact Strength, Temperature

(-192 0 C to 1032 0 C)

20. ABSTRACT (Conlinuet on reverse aide ft necessary and Identity by block number)

A study was performed to determine the effect of temperature on the impactbehavior of two XDTM processed TIB2 reinforced TiAl Intermetallic composites

(IMC's). An existing instrumented tup drop tower apparatus was modified for theprogram. The IMC compositions were Ti-49 at.% Al + 5 vol.% TiB2

FOR•M ii i i.. .

DD I JAN 73 1473 EoITION OF I NoV 4S IS OBSOLETE UNCLASSIFIEDSIN 0UA2-OG4-660 I 1

SECURITY CLASSIFICATION OF THIS PAGE 00`1-n 1)-(-n~f~i

SI '111 ' y C.A A , IF t(_ AT 1H Or I I 741, AG'E(WhI D-( A. rfn4.f.d)

and Ti-48 at % Al + 10 vol.% TiB . - The specimens were notched to an a/w ratio2of 0.2. Details and test procedures for the modified apparatus were presented.Test temperatures ranged from -192%C to 1100%C. Impact toughness and maximumbending stress for both IMC's decreased from room temperature to temperaturesas high as 1100%C. An important experimental, observation which supports theseresults is the change from transgranular cleavage to incergranular fracture atthe 760%C test temperature. Also noted is the possible contribution todecreasing toughness of unfavorable difference in coefficient of thermal ex-pansion between TiB and the matrix with increasing temperature. Data repeata-bility and verificaiion of the ability to observe high temperature brittle-to-ductile transition behavior established confidence in the modification of theexisting instrumented tup apparatus,

0ooSSo10 For

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I NTRlIODUCTlION

Htigh p~erformfance propuIlsion systems and1 structures for Ihypersoniic vehicles

rqiii iire advanced mi aterials. Tlhese materials must have strength, ductility, tough ne~s.s

and1( resistance to oxidation at. high temperatures. One family of high temperature

materials are inteimetalhc compoundls. An early sumnmary aind review or their

p~roper'ties was providedl by Westbrook (1). lie noted their principal mechanical

- ~~claracteuisitcs were brIit~tleness and extreme hardness. Also, lie p~ointed out the vecry

carly work or raminan and Dahl (2) in which they performed impact tests to classify

int ernietallic comp)ounds on the b~asis of the temp~eratuire dlependlence of their

(Iiicti le-bi)ittle bleh avior. The iy observedl low valutes of room tern iera~ture dIucti lity andl

impact toughness.

More recently, for- the high strcngtlu-to-wcight ratio and stiffnless required for

aerosp~ace applications, titaniumi aluminniles, such as, Ti 3 A and TiAl were id~ntirimd

as having the dlevelop~ment potential to meet high temperature reurm ns.lliese

I ~aluminicles axe (lesignated no ai~l I, respectively. Elarly work on thme elevatedl

tenipleratuire deformation and fracture of -r-a~ltinlinides was reported 1by Lipsitt, 0, al

(3,4I). They indica~te(] a, (uctile-to-lbrittle transition temperature (mvi-TT of about

7000C Th lie ^y-a unlninidles, howvever, have more senlsitivity 1.o room temiperatLure

1wbitldeness than the q alloy. Activity on the n, 2-Ti 3 Al type alloys followed and the1

imost. recent effort, is summ-a~riz/edl in the work of Blackburn a~nd Smith (5). M'ore

I ~recent activity on titanium aluninides has b~een sumniarixed by K~im (6). lie reports

on all their attribuites, but still notes their low fracture toughness at low to

intermedc~iate temperatuires. Ilie note., that activi~ty in the last, several years has

provid(edl some Suiccess th iom igh chemistry modlifi cation atnd in icrostrc,nrm uie control by

I i iimproved p~owdler met~al Inrgy p~rocessin1g.

Dur i ng the 0171 me tat iwii temea IIics were uinder (levelopni enii, mui ces in ii Meal

ii1iti'ix comp)C)i tes (i.e., mimeta"ls rel ii orced wi th c~ernl.1c particles) wnas accomplhisliedl

The development of an intermetallic matrix composite (IMC), therefore, is an obvio,.s

extension. A technology to achieve IMC's was recently accomplished by the Martin

Marietta proprietary XDTM casting technology. Some microstructural and

mechanical property information -,! a mixed a2/' intermetallic alloy reinforced wit

TiB2 ceramic has been reported by Christodoulou et al (7). Room temperature

toughness values of 12-14 MPa (m)1/ 2 were reported for the lamellar structuie.

Impact toughness and DBTT's have not been reported for these new IMCs.

The present study is to determine the effect of temperature on the impact behavi(o,

of two XDTM processed TiB) reinforced TiAl IMC's. In order to determinie the

variation of impact. toughness from low to high temperature an existing instrumentd

tup impact drop tower apparatus had to be modified and new procedures develop×ed

to obtain meaningful results.

EXPERIMENTAL DETAILS

Materials

Machined blanks of two near gamma TiB 9 reinforced TiAl IMC materials were

obtained. The blanks were unnotched with a 12.5 x 12.5 mm cross section and

63.5 mm length. The compositions were Ti-49 at.% Al + 5 vol. %X; TiB2, and Ti-IS

at.% Al + 10 vol. % TiB2, and they were identified as lots 82XD and S3XD.

respectively. Both materials were isothermally forged below the transformation

temperature at the (a' + 1•)/(a,• + "y) boundary shown in figure 1. This phase

diagram of the central region of the Ti-Al system is due to McCullough et.al.A'e A

representative microstructure is shown in figure 2 from the S2 ND material. TiB.,)

particles are uniformly dispersed in the (. 7+ o.))/ lamellar matrix. T1e spe1cimens

were notched with a low concentration diamond saw. Oil lubricated. multiple and

minute cut depth saw passes were made to a final notih depth ratio. ai. of 0.2.

2

The notch width was 0.3 mm with the notch tip radius of 0.15 irm. After nouchil!,.

the specimens were washed thoroughly with acetone and dried in lab air.

Impact Test Apparatus

An existing drop tower with an instrumented load tup was modified for th.-

present study. The apparatus is shown in figure 3. Impact velocity is controlled Lkv

drop height, and impact energy by the addition of weight to the tup head carriaige.

Test velocit.' for the present study was 1.5 m/s, and the impact energ\' was 5.S J.

Data acquisition from the instrumented load tup was obtained from an analog to

digital interface in a p.,sonal computer. The number of data points per test, is 10224

load-time pairs with a total recording window adjustable between 5 and 2.5

milliseconds. Data reduction was accomplished by commercial software:

Details of the test procedures and modifications to the existing drop tower

apparatus for high temperature testing are as follows:

a) Specimen Notch Alignment-

Before the impact test, specimens were positioned on the drop tower anvil using

a machined positioning jig for centering in the long axis direction and by centering

marks on the anvil in the short axis direction.

b) Data Acquisition Timing-

The data acquisition start flag is attached to the tup head carriage which

passes through a capacitive sensor and initiates data acquisition, as shown in fi'gue3. Due to the possible brittle nature of the test materials the time to failure can he

very short. Some of the XD samples were found to fracture in less than 0.25

milliseconds. Thus. a barrel micrometer was mounted on the start flag gate to

adjust for precise data acquisition start times. The trigger start height was s,:l io

initiate data acquisition 0.3S mm before tiup head/sample iI)actp .

3

c) Heating-

Other investigators have attai,.d high temperature testing, by heating the

specimens in an external furnace and then transferring the sample to the inpact

apparatus for the test (9). To evaluate this method for use in the present study a

temperature instrumented sample was heated, and it was found that after transferring

the sample, temperature decreased at a significant rate before impact occurred. This

method, therefore, was determined to be unacceptable. Winsa and Petrasek (9) also

used another heating method in which multiple propane torches were used to attain

temperatures of 1099 0C. The latter method was tried using an oxyacetylene torch

with some degree of success except that some materials were reactive to the ,zas

torch. An approach to attain equilibrium high temperatures rapidly was suggested

by the work of Hartman et al (10). Thus, four water cooled quartz infrared line

heating lamps were utilized as shown in figure 3. These lights were controlled by a

potentiometer for heat flux adjustment from zero to 100 percent along with

individually controlled powered switches to provide ei,!hrr two or four lanmp heating.

For all the testing reported herein 4 lamps were used.

As shown in figure 4, temperature versus time tests were performed on a

specimen from the S3XD material to determine the time to achieve internal

equilibrium temperature required at various power settings. The sample temperature

measurements were made using a 0.005 inch diameter chromel/alumel thermocouple

inserted into the notch and held in place with zirconia fiber. The zirconia fiber also

prevented the thermocouple from being exposed to the direct radiation of the healing,

lamps. Since the notch width was greater than tije thermocouple diameter. no stress

should be present from the thermocouple insertion and zirconia insulation inside of

the sample notch. For the results reported herein the specimons were heated for five

minutes to achieve internal temperature equilibrium.

4

(1) lnstriirrerit~ed l 1 lj ead heat P~rotectioni

To( pro)tect the jl in 1-1111en(d1.1ii ) head from- the lowe'r ci ai iber hevat (rfig. 3), Ow

till) hleadi was pl)aced ini a standbIIy p)osition that was a large (hist~ance Fromi the uipper

(ilallibler to avoid coliwe(t~ive heating from11 thc lamps. Cooling or the till) head when

placed in the ready position was achieved iby a stainless stnoel, overlapping, m1anlual ly

activ~atedl, Iiliquid nitrogen cooled ''trap dloor"' which providled a tLhermai barrier

lbetweeni the lower chanibe)r and1( the till he~ad. lDesired low Lu p imnpact v'elocitby

requlired tile tillp head to 1)0 Very~ closo to the lower sjpeci en hieat~inrg cilamiber.

Sinrce the inistriimenited till1) hei'd ( hard no temnperature conlpensa.Lioil andl was (designled

tLo operalte art. room1 temll~era Lure, the temiperatLure in the upper cllamlber (position or

the Limp head in the readly p~osition) was mianually rmaintained at 150 to 20'C. TPhi-s

occurs Concurrently while thle Samjple is being heated in the lower chamiber. Wl~ieim

the uipper chamiber hadl achieved the p~roper temnperature (i.e., 20 0 C) the tup11 head

wvas lowveredl to tihe readyv positLion. When tile rive m1inuiito sal niple hueatinrg p~eriod was

comiplete, thle "trap dloor" wvas opened and the hip head releasedl fromn the readly

p~osition to im-rpact the sample. Imninediately upon fracture, the till head was

retra~ctedl t~o the sta~ndby position and the heating lamnps were extingulishedi.

In order to confirmn that, thme modification oil the existinrg i 11st,riiiienteol ed drop

tower system andl possible effects of high and low temiperature test~s onl tile

iisthuinienteol till, almlminui i) loadl calibration stamidarols were tested before and a~fter

the t~ests. These tests verified that the instrumented till load mneasuremnent was in

cornpiia~nce after thle low and~ high temrperature tests. Also, to check the systemn's

ahIbi ity to (leter-nline inc~reased touighneiss at, high telflI)Ciatuires, 1090 Ilot, rolled (lII.)

carbon steel Charily speciniolns were Lestedi at, 20 0Cq 300 0 C 1c i)000c. rihe resuiDt, arv

shown ini flg~re I. These resul t~s con firni t~he systemn's ability 1,o Iviiiasuire r~isi ng.

t(Htghliess at, hiighi telfli)Cra ILure.

RE'SULTFS AND) DISCUSSION

'rl tntl111ne ,1)ilpc est. provides a. lad - timle hist~ory as showni hi

features are inertial loanl, as dIiscu1ssed in reference 1], sample vibrationa~l

chlaract~eristics aind die maximum INoa(l. rilie st~eel) (irol off in loadi after inaxi mimlil

loadI is charactecristic of a lm-RIttl material. From the maxi mum load values al, room i

temper~ature, maximum b~ending stresses of 472 M11a and 4168 M ~a. were calcudltedl for

82XD and] 83X1), respectively.

Impact0 loa.(-61ime hlistorieS at. theC various test, temperatur('s from 192'C to

1 0320 C for the 8:3XD imaterial a-re given in figure 7 which shows thle inertial loadlan 'bafiona~l chara~cteristics ror all t~emperatures t es t a.''m odt edt

is integr-at~ed by thle Colnpui 1.0. software to p~rovidle thec tot~al energy absorbed by Owli

specimen from inim ltact. 10 fra cthire. Thie l1 rendl of thle energy ablsorb ed (i.e. tou1gh itess)

allong withl the maximuilm load values, versuis test temperatures ror- both the 82X1) and

83XD 1MG materials are shown inl figure 8. Both of these properties are maximum

it, roomn t~emperature and (decrease significantly as temperature increases. 'rilhe t~wo

IMIC's, one with 5 vol.% dlispersedl TiP9 particulatle and lilte oilier with 10 vol.%,

produlcedl very close absorbed energy and maximum- load results.

The above t rend(s of dlecreasing impact toughness wvith increasing temperal.u ie

are reflcted in the estimated lplane-stra~in fracture toughness, 1K Th VK~ aluaes al.

toi emperature (are 25.4 MPa(m)'/ for the 82XD IMC a~nd 24A' M Pa(mn) /2or

81X!). TPhese Values decreasedl Lo 10. 1 MI a(m1) 1/2at 11.56 0 C for 82X1) and~ 10.5

Nil P'1a(Inl) 12for 83XDI at, 10320 C, One( possible contribit~ion L~o the (lec~rea'sv in K<

%vi thl iincreasi ng teniperalture migig t be t,iie unfavorable difference iewieen ow menatri x

and p~attictatf' coefficiviam or ofw,hmra exasi(T1 Compar11isonl of C'1'l v'al I vs

6

vrVsI, teviIn)peraur, Ifrom rl((!'rvlccs (7) and (12) for the Ti12 rivinfore(Ied -' TiAI

natm-rix andl T'j Il. pa rticul ate, Show the CTPE fror Till,, to be less It haln lhe nIl atrix ait

temperatures rrom 20 to 1000 0 C. Titls chiaractLerisLiC would inipose all tiflfavorahl(,

thermtal stress in tihe mlaterial as teeml)erat.ure increases with a subsequent, decrease ii

fraetIt'c loughness.

Only the 83X1) (10 v/o '1i' 2) was tested at - 192 0C. The energy absorhed

a.nd mnaxi mum Ioa.d values were less than those at. room temperature (i.e., 200 C).

Since It hese proplerties decreaseed ahove room temperatures, it was anlticipaled Ihi at. 1.1tv

abl)50r)ed lenergy and ma(xi mumn load values ,at, - 1920C would he slightly higher lha I

those at room temperatil re. Au explmation of the low tenll)eratlure result, is nol,

appllarenlt.

After the i•lpac, t.tests, I ockwell-C lin.rdnesses were measured on ile rooml

t,enlp(era.l re aid the highhest tlemperatiure test, samples. There was no change in 1.hw

siltrface hard-ness aftler hie higl t temperat, ure tests. The IRockwel l(-C, values were 10

and :15 for the 82X!) and 8:IXl) materials, resl)(ectively. 'ITlh higher vale for 8Im 3X1)

confirms the higher Till') volume fractiion.

Stereo pair scanning electron microscope (SEM) microfract-ography was

performed on tihe fractiure snr faces. As shown in figure 9, as the impact, test,

temperature heconlis 7(i60C and higher, tile fraciire morp)hology changes from

transgranilar cleavage at, room temperaturp to an even lower fracti Ire totughness

mechanism, that is, classic inntergramular fractume. The SEM fractography, therefore,

yields an explanation for the impact toughness results. The int.ergranmlar fracture

also illustrates the fine grain size achieved in the test, materials. An estimatle

suggests a grain size tlumrl' ill excess of 10.

7

C'ONC'IAJS IONS

lImpfact. toughness andl maximium b.endhing stress for 5 and 10 vol .% Till)

reinforcedl XI)-TiAI IMCs dlecreased from room temperature to t~emperatures "s high

a)s 1100 0C. Ali important experimental ob~servation which supports these rcsull-s is

t. e (Change from t~ransgraiiul r to in tergrani'ilar fracture ait the 760 0 (" test,

lomemjratulre. Also noted is ILhe possibl)e contrib~ution to dlecreasing toughness of

unfavorable dlifference in CTE between TiB9 and the miatrix with increasing

temperature.

D~ata. repeatahili ty andl verilfication of thle aIbility to observe high tell]perahture

bri ttle-to--duictile-t-tanisit~ioui behavior established confidence in the instrumented tup

(drop towver modlification and p~rocedlures for high temperatures implact toughness

ACKNOWLE-DGEMENTS

Thel1 authors wish to aIcknlowledge the supplort of the Office of Naval Rcse~.,-chl

under Contract No. N0001492WR2'1016. rphe specimnens were provided from a

DA\RPA progr~am adlministeredl by C. R. Crowe of the Naval Research Laboratory.

Also, we appreciiate the efforts of i.. E-. Clemens, Engineering, Librarian.

REERNCES

G. . T~amman and 1'. Da~hI, Z. Anorg, Ailgem. Chenm, 126, 1923, p). 124.

2. J1. 11. Wcstbr-ook, "Historical Sketch," in Tnternieta~lhic Co-inouinds, John WileyS~Sons, Inc., 1967, p). 3.

3. 1), Schectman, M. I1 Blackbirn andl 11. A. Lipsitt," The 1)cfoimation a1(lFracturec of TPiAI at, Room Templeratulre," Met. Ti'ansm., 5, 1974, pp 1373-81.

41. 11. A. Li psi tt, D). Schectnuan andi it. i.. schiarriik, ''The Imeornuttion andiFracture of TiA I at Elevated Temperatures," Met. TIrans. A, 6A\, Nov. 1975, lpp

1991-1996.

5. M. J1. Blackburn, M . I1. Smithi, "Imiprove(I To,,ghness Alloys Blasedl on 'Pil,a~niumAhiminides," W'RI)C-TR---89--.l095, 26 Oct. 1989.

6i. .1. WV. Kim, "Interinealiic, Alloys Based on Glammia Ti1tanium Altiminide," I.1of Metals, 41 I, 1989, pp) 24-30.

7. L. Christodoulu, 1P. A. Parrish and( C. R.. Crowe, "IXDT Titanium AltininideComposit~es," in High Teilneralureffli gil Perrormainee-Compiiosites, edls. F. D.Lemikey, S. G. Fishmani, A. G. Ev'ans andl J. It. Strife, MRI~S Proceedings, Vol.120, 1988, p1) 29-3'1.

S. C. McCullough, J. J1. Valencia, 1I. Mateos, C. C. Levi, It. Mchra~bian, and 1K.A. Rhiyne, "Thie uigh, Temperauire Alphia Field in the rpitani~ur-AluminuinPhase Diagram," Scripta, Met. (22), No. 1, 1988, pp 1131-1136.

9. 11 A. Winsa and D. WV. Petrasek, "Factors Affecting Miniature Izod ImpactStrength of Tungsten Fiber Metal Matrix Composities," NASA TN D-7393,Oct.. 1973.

10. G. A. Hiartman, L. P. Za-wada andl S. M. Russ, "Techniques for, ElevatedTemperature Testing of Adv~anced Ceramic Composite Matecrial," in P roceedling~sof the Fifth Ann ua.l Hlosti le Envir-onment~s and Hli gl Tenmeratu re MeasumrermeniisConference, The Society for Experimental Mechanics, March 1988, pp 31-38.

11 . 11. J. Saxon, D. R. Ireland, ain(1 WV. L. Server, "Analysis andI Control of Inertial1Effects During Instrui-ente(1 Impact Testing," Instrumlented1 Impact TJesting,AST-M STP 563, 1974. pl) 50-73.

12. MI. Taya, S. hI-ayaslii, A. S. Kobayashi and 11. S. Yoon, "Toughening of aParticuilate-Reinfor.ced/Ceramic-Matrix Composite," University of Wash ingt~on,Technical Report. No. IJWA/DME/TR-S9-2, ONR Contr~act NOOOII-S7-IK-0326,Sept.. 1989.

9

1600- L

1400 elf tL

J. I #.

a- ~ -,,Y..•_ ... _

00 -

340 40 50 6Atmi Pecn Al

Fi r I - II# • / "

- r'

- I

S1 t I

V *

I I -It

I 1

a I

.... I... " l .... F I ' I -' --

30 40 50 60Atomic Percent A1

Figure 1-Central Area of Ti-RI Equilibrium Phase Diagram

Figure 2-Flepresentatiue Microstructure from 82HD IMC

iCi

lup [ic-Lid Roi"

Upper Ichambcr rr2tNr

TrpI

- j-S to ncl

Ilead-t-

Heot 1jJ,LO... ...br~ ,'> ', .:;// / /

Anvd -'

Figure 3-M odified Drop Tower for High TemperatureInstrumented Impact Testing

83XD Temperature ProfileThermocouple in Notch

Temp dog C1200 K

100%

1000.%25

800 -:20% - - --

6005

400

200 -

0 -

0 60 120 180 240 300 360 420

Time (Soc)

Figure 4-Temperature-Time Profiles in the 83H0 IMCat Various Power Settings with 4 Heating Lamps

Impact Energy vs. Temperature1090 HR Steoo

60

50 1--- ---,40

0)30

Li 20

10

i, 1 10 , IF[ act.t. C

00 200 400 GOO 800 1000 1200

Temperature (C)

Figure 5-Impact Fracture Energy uersus Temperaturefor 1098 HR Steel

82XD Repeat Comparison20 deg C

Load Lbf Load K NA2500>

¾10

2000 4- fl,2 X 0 4 f4T

1500 82XD-GPT

6

1500-- 24/

0- 0

500-- -2

-500 -i-H -V I- ii -I+- li iF--Hl lli-Hl -ii- H• . . ... , 2

0 50 100 150 200 250Time (microseconds)

Figure 6-Repeat Comparison of Load-Time Histories for82HD IMC Specimens Tested at Room Temperature

83XD TiAi Load vs Time vs TempEquilibrium Temperature k r,

2.5

2 X

0--1C

O 150"C3 ,0 C

db p.1</..' 3 0 , -

x5100 70 C

""1032••

o 50 100 150o 200 250Time (imicroseconds)

Figure7-Load-Time Histories for 83H0 IMC SpecimensTested at Various Temperatures

82 & 83XD Max Load & Total EnergyVS

Energy J Temperature Load kN

3 Max Load 83XD Totia Energy

-, 83XD Max Load

82XD Total Energy

•" "K 82XD Max Load

,- Total Energy

"-2

01 - -. -- 0

-400 -200 0 200 400 600 800 1000 1200 1400

Deg C

Figure 8-Maximum Absorbed Energy and Load versusTemperature for 82XD and 83RD IMC Materials

(a)

(b)

Figure 9-SEM Fractographs of 82RD IMC Material Tested

at (a) 20 0 C and (b) 760 0 C