This article was downloaded by: [Johann Christian Senckenberg] On: 09 September 2014, At: 00:23 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Materials and Manufacturing Processes Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lmmp20 Laser Induced Liquid Phase Reaction Synthesis Assisted Joining of Metal Matrix Composites Narendra B. Dahotre a , T. Dwayne McCay a & Mary Helen McCay a a Center for Laser Applications , The University of Tennessee Space Institute , Tennessee, Tullahoma, 37388 Published online: 25 Apr 2007. To cite this article: Narendra B. Dahotre , T. Dwayne McCay & Mary Helen McCay (1994) Laser Induced Liquid Phase Reaction Synthesis Assisted Joining of Metal Matrix Composites, Materials and Manufacturing Processes, 9:3, 447-466, DOI: 10.1080/10426919408934917 To link to this article: http://dx.doi.org/10.1080/10426919408934917 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
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This article was downloaded by: [Johann Christian Senckenberg]On: 09 September 2014, At: 00:23Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK
Materials and Manufacturing ProcessesPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/lmmp20
Laser Induced Liquid Phase Reaction Synthesis AssistedJoining of Metal Matrix CompositesNarendra B. Dahotre a , T. Dwayne McCay a & Mary Helen McCay aa Center for Laser Applications , The University of Tennessee Space Institute , Tennessee,Tullahoma, 37388Published online: 25 Apr 2007.
To cite this article: Narendra B. Dahotre , T. Dwayne McCay & Mary Helen McCay (1994) Laser Induced Liquid PhaseReaction Synthesis Assisted Joining of Metal Matrix Composites, Materials and Manufacturing Processes, 9:3, 447-466, DOI:10.1080/10426919408934917
To link to this article: http://dx.doi.org/10.1080/10426919408934917
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in thepublications on our platform. However, Taylor & Francis, our agents, and our licensors make no representationsor warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Anyopinions and views expressed in this publication are the opinions and views of the authors, and are not theviews of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should beindependently verified with primary sources of information. Taylor and Francis shall not be liable for any losses,actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoevercaused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions
Materials and Manuftu:/uring Processes VoL 9, No.3, 447.466, 1994
Laser Induced Liquid Phase Reaction Synthesis AssistedJoining of Metal Matrix Composites
Narendra B. Dahotre, T. Dwayne McCay, and Mary Helen McCayCenter for Laser Applications
The University of Tennessee Space InstituteTullahoma, Tennessee 37388
Abstract
A Laser Induced Liquid Phase Reaction Synthesis Assisted Joining technique isemployed for SiC-particulatelAI-alloy composite to produce joints. Joints inSiC/AI-alloy composite are produced by synthesis of suitable material productas a result of interaction between composite and Ti (or Ti-alloy) reactive fillermaterial induced by laser energy in the joint region. Such reaction productminimizes or eliminates the formation of deleterious aluminum carbide phase inthe joint region depending upon the type and nature of the interfacial reactivefiller material and also the laser processing parameters. A laser beam is utilizedto both synthesize the interfacial reactant mixture and to heat the base materialadjacent to the joint region to minimize the thermal stresses. The technique alongwith suitable filler material, further can be extended to a variety of metal matrixcomposite systems including combinations of Or/AI, B/AI, B.ClMg, Steel/AI,W/AI, AI20:/AI, and Gr/Cu which are excellent for use in various automotive,aerospace and electronic applications. Preliminary observations describing theproof of concept of laser induced reaction joining of metal matrix composites arereported.
1.0 Introduction
Recent efforts in development ofmetal matrix composites (MMCs) havebeen directed toward synthesis ofparticle dispersed materials, part by dueto the cheapness of the particles and thelow cost associated with the synthesis ofcomposites (1-4). Particle dispersed
MMCs such as SiC particulatelAI-alloyare now widely used for structuralapplications due to properties such ashigh strength, light weight, low thermalexpansion, good thermal conductivityand high wear resistance compared tomost monolithic metals, polymers, andceramics (5,6). Existing and potentialapplications for metal matrix composites
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include, sic/AI airframe structures (5,7),aircraft speed brakes, automotive frontdisc-brake rotors, diesel engine cylinderliners, automotive engine connectingrods and turbocharger impellers (8),AlP/AI automotive drive shaft tubes(8), Gr/Cu space power radiator panels,heat exchanger material for hypersonicaircrafts (9, I0), electrodes for powersemiconductor devices (II) and SiC/AIhigh power, high density electroniccircuit enclosures and packagingsubstrates in integrated circuits (12-15).In many of these applications it is alsodesirable to fabricate the MMC intocomplex shapes via joining processes.This can be achieved only if the MMCscan be joined to similar composites andstandard structural metals and alloys. .without any major reductions in strength.Thus, a critical need exists to developreliable joining procedures forcomposites.
In c o ri v e ri t i o n a l fusionwelding/joining techniques such as gastungsten (16-18), resistance (19-21) andplasma (22) welding of compositesystems such as Steel/AI, W/AI,AI20/Ti, WITi, GrlTi, Gr/AI, B/AI,B4CIMg, and SiC!AI, the reinforcingmaterial is exposed to a superheatedmolten matrix for extended time periods.This prolonged contact results inaccelerated reaction rates between thematrix and the. reinforcing material,leading to extensive interdiffusion,reinforcing material dissolution and evenits complete destruction. The extent ofinteraction between the matrix andreinforcing material depends upon thebase material and the thermal history to
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which it is subjected. Thus priortechniques proposed for fusion weldingof MMCs pose problems and fewmethods can produce joints withcontrolled properties and withoutdegradation in strength.
Other techniques such as diffusionbonding have proven useful forproducing joints with good elevatedtemperature properties. However,because these methods frequently requirevacuum and/or hot pressing equipment,their practicality is limited. An alternatetechnique, that allows efficient joining,is the use of either mechanicalinterlocking or mechanical fasteners.However, the lack of ductility and thepossible severe stress concentrations atthe joint can result in catastrophicfractures.
The above described techniques suchas mechanical attachment, diffusionbonding and, fusion welding are eitherprohibitively time consuming andexpensive or produce weak and defectivejoints due to the formation of deleteriousphases within the joint region. Thus, alack of understanding of fusion energyeffects exists on the joining of MMCs. Areview of the open technical literature(22-25) revealed few studies devoted toMMC joining and cutting. Except for thepresent authors (26-30), almost no workhas been devoted to welding of MMCsusing the laser technique.
One approach to producing soundjoints with integrity and strength is byLaser Induced Liquid Phase ReactionSynthesis Assisted Joining outlined inthis paper. This technique can producejoints in MMCs that can enhance the life
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Laser Induced Joining of Metal Matrix Composites
of components made from thesematerials for structural applications.Since the laser operating parameters canbe precisely controlled, the thermalconditions will be sufficient tosynthesize suitable reaction product as ajoint material and produce both. aminimum reaction zone with a minimumimpact on the microstructure near thejoint. The technique would also allowthe tailoring of the microstructure in andaround the joint.
2.0 Related Worl<
Prior studies on laser processing of10 and 20 vol% SiC particulates/A356AIcomposite have demonstrated thefeasibility of laser welding/joining (2428). The microstructures of thesecomposites in as-recei ved condition areshown in Figure I which consist ofdistribution of SiC particulates alongwith primary silicon particles in thematrix. As composites were synthesizedusing casting technique, the distributionof SiC particulates appears to behomogeneous. The composites (75 x 25x 3 mrrr' in size) were subjected to beadon-plate welding using a 3 kW CO2
laser. In the first set of experiments thesamples were laser welded in continuousmode at specific energies varying from5.3x103 to 13x103 J/cm2 (26), and in thesecond set of experiments, the laser wasoperated in pulsed mode with dutycycles ranging from 50-91 % (27). Inboth cases the traverse speed was 25mm/sec and the focal position was 0.5mm below specimen surface. Argon gaswas used as an assist gas at 4 Llmin.
In both experiments, microstructuralobservations of the laser processedsamples showed that the fusion zoneconsisted of mixture of aluminumcarbide (AI4C~) -and SiC particulates(Figure 2). The morphology of thealuminum carbide was plate-like, whichis very brittle in nature, and deleteriousto the MMC because it degrades theengineering properties of the material(25,27). The size and amount of theseplate-like structures. varied according toheat input. These observations revealedthat the extent of reinforced material(SiC) and matrix (A356AI) reaction isdirectly proportional to the laser energyinput. As energy input increased, SiCparticle dissolution became greater andplate-like structure formation increasedin both size and quantity. From theseobservations, it appeared possible tocontrol the matrix and particleinteraction during processing bycontrolling the amount and mode(Continuous or Pulsed) of energy input.The high cooling rate and increasedsolid solubility associated with the laserprocess also produced non-equilibriumphases, including CuAI 2, MgSi03,
MgAIO and AI-Fe. Existence ofdislocations and these fine nonequilibrium phases in the matriximparted higher than base materialhardness values to the fusion zone andfor duty cycles of 67% and 74% thetensile properties were comparable to thebase composites.
The favorable results from theseattempts (26,27) on laser processing ofSiC/AI-alloy composite suggest that bycontrolling the amount and mode of
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Laser Induced Joining 0/ Metal Matrix Composites
interface between the workpieces,resulting in chemical interactionfollowed by creation of a butt joint. Thelaser processing and material parametersused for this study are given in Table 1.
Laser induced reaction butt joinedMMC samples were cross sectioned andmetallographically polished usingstandard techniques. The final polish waswith a 3 urn diamond paste. Specimenswere etched with Keller's etch for timessufficient to reveal the structures ofinterest. The micro-structures wereobserved on optical. and scanningelectron microscopes. Quantitativecompositional analysis was performedusing X-ray energy dispersivespectroscopic (EDS) analysis techniqueon a Cameca-MBX microprobe operatedat 25 KV and 30 nAbeam current.Analysis was conducted with a focusedbeam (8 urn diameter) in the spot mode.
4.0 Results and Discussion
An overview of the typical laserinduced reaction butt joined MMCillustrating topographical features isshown in Figure 3. The joint consists ofa fusion region in the center surroundedby partially melted zone (PMZ). Similarfeatures were observed in both 10 and20 vol.% SiC/AI-alloy composites joinedusing different laser powers (1200-2700watts). Figure 4 is an optical micrograph of the cross section in a laserinduced reaction butt joined MMC. Thefusion zone shows the existence of someparticulates and complete absence ofplate-like (aluminum carbide)precipitates unlike those observed in the
autogenous laser joined MMC samples(Figure 2) (26-30). The regionsurrounding the fusion zone describedearlier as PMZ, consists of partiallymelted and physically altered SiCparticles in a fine cellular matrix. Thepartial melting also resulted in breakingthe clusters (usually observed in asreceived cast composite) and uniformlyredistributing them in the PMZ. Thevariation in the microstructure from agiven location in the fusion zone to alocation in the unmelted region in bothcomposites follows the same trend forall laser conditions used in the presentstudy.
The high magnification scanningelectron micrograph of particles infusion zone is shown in Figure 5. Thechemical compositions of these particlesand the particles in PMZ along with thechemical compositions of thesurrounding regions in both zones aresummarized in Table 2. The table alsogives the possible reaction products inthese regions. The most of the particlesin the fusion zone were TiC particles(Figure 6), however, a few particles ofTiC appeared ri.ch in Ti and Si contentssuggesting possible diffusion of Ti andSi into the surface. Similarly, a majornumber of SiC particles (Figure 7) alongwith a few SiC particles rich in Al wereobserved in the PMZ. The existence ofsome TiC particles in fusion zone andSiC particles in PMZ with possiblediffusion of Ti, Si and Al into thesurface can aid in improved wetting andchemical bonding with matrix material.Similar observations were conducted bythe present authors (27) and other
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10000.
9000. (C) AI Locatiion B8000.
7000.
6000.III
3 5000.0o 4000.
3000. l~ Si2000.
mo. i C Ti Ti.J \. r-;
00 t 2. 3. 4. 5. 6.
KeV
Figure 4c: Microstructure and EDS spectra for elemental analysis of laser inducedreaction joined 10 vol% SiC/AI-alloy composite (Delivered power: 2100watts) EDS spectrum at location B.
Figure 5: Scanning electron micrograph of particles in fusion zone of the laser inducedreaction joined 10 vol% SiC/AI-alloy composite. (Delivered power: 2100watts)..
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,.I'; .
Iii(,
( ,.\ ..
lOOO.
900. (b)BOO.
700.
600.CII
~500.
400.
300.
200.
lOO.
1.
Ti
6.
456
Figure 6: Existence of carbide particles in fusion zone of the laser induced reactionjoined 10 vol% SiC/AI composite. (Delivered power 2100 watts). (a)Microstructure of TiC particle' and (b) EDS spectrum showing elementalanalysis of the particle.
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Table 2. EDS Elemental Point Analysis of Laser Induced ReactionJoined MMC
Location of theMicrostructural Composition, Atomic Percent Possible
researchers (31) in the laser processedand as-received MMCs. The EDSchemical analysis also revealed thepresence of some SiC particles in thefusion zone. It appears that these are fewSiC particles which survived an intenseheat conditions during laser joining.However, due to their occasionaloccurrences, no attempts were made toquantify such particles. In addition tothese variety of particles, the presence of
458
various other reaction products in thejoint interface were also detected (Table2). The high cooling rate and increasedsolute solubility associated with laserprocess produced the complex phaseswith different proportions of AI, Si, Tiand C. The heterogeneous distribution ofthese complex phases is expected toresult in a wide variation in local workhardening rate within the joint region ofthe composite (26,27).
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During autogenous laser joining ofSiCIAI-alloy composite, plate-likealuminum carbide phase is formed bythe following reaction (32):
4Al + 3SiC :: AI4C3 + 3Si (1)
Excessive formation of Al4C3 results ina brittle joint that can react with wateror moisture (33). On the contrary, whenTiC is formed, instead of AI4C3 in thejoint region, it is expected to enhancethe joint properties since TiC hasexcellent thermal stability (33), meltswithout decomposing at 3343K(A14C3
totally decomposes at this temperatureunder one atmosphere), is denser (4920Kg/m3
) compared to SiC (3210 Kg/m3)
(34) and A14~ (2950 Kg/m3) (35) and is
also harder (2800 Kg/rum') compared toSiC (2400 Kg/mrn') and AI4C3 (1950Kg/mrn") (33). In the presentexperiments this was achieved by usingTi (or Ti-alloy can also be used) as areactive filler material to facilitate theformation of TiC instead of Al4C3 (Table2 and Figures 5 and 6). Interactionbetween carbon (from SiC) and Tiproduced the carbide phase (TiC), asolid solution (u-Ti or B-Ti) or acombination of phases (TiC + Ti or TiC+ C), depending on the experimentalconditions and the characteristics of thestarting material (36,37). For example inthe case of 47 at% C + 53 at% Timixture, material exists as a two-phasemixture ofTi and TiC (Figure 8). Basedon earlier analysis of the resultantproducts (Table 2) it appeared thatduring laser induced reaction joining themelt pool attained the level of C and Ticontents which resulted in formation of
TiC, and (TiC + Ti) mixture in the jointregion. Ti in such mixture then aids inincreasing the surface energy andwettability of MMC (38). Thus, TiC isformed by the reaction:
Ti + SiC = TiC + Si (2)
Since the Gibbs free energy changefor formation of TiC is substantiallylower than that of AI4C3 (39), it is lesslikely that AI will be involved in aspontaneous reaction with SiC as shownearlier in eq.(l). However, there is alsothe possibility of a secondary reaction inwhich TiC reacts with molten Al to formA14C3, according to (40):
3TiC + 4AI = Al4C3 + 3Ti (3)
The positive value of 350 kl/molobtained at 1553K for this reaction (40)suggests that TiC is stable againstreaction with Al and will not favor theformation of Al4C3 through this route.According to equation 3, TiC has asubstantially lower free energy offormation than AI4C3 over the full rangeof temperature up to 2073 K, asillustrated in Figure 9 (4 l). Hence, thereaction in equation 3, always favoredthe formation of TiC over A14C3•
The participation of titaniumcarbide in the interfacial reactioncompletely prevented the formation ofplate-like structures (Figure 4). Areactive element such as Ti used as aninterfacial filler material increases thesurface energy and improves the wettingcharacteristics of the base material viaformation of various reaction productssuch as AI3(Si,Ti)2' AI6(Si,Ti) (Figure 4),AITi (Figure to) (Table 2) at the
interface (38,42). The detailed analysisof several of identified and unidentifiedphases generated in the joint andsurrounding region during laser inducedliquid phase reaction synthesis assistedjoining is being currently conducted fortheir structure and morphology usingother analytical techniques.
Further additives such as elementalNi in the reactant Ti powder or Ni in TiNi alloy used as reactive filler materialserve as a diluent thereby notparticipating in the reaction. However,they may decrease the interfacial
reaction temperature (2937 K for 0 wt%Ni to 2002 K for 25 wt% Ni) (43). Sucha decrease in reaction temperature alongwith the presence of a neutral liquidphase will reduce thermal shocks in thebase material. As shown in the Ti-Niphase diagram (Figure 11) (44), aneutectic forms at a Ni content of 30wt%. As a result of this, a Ti-Ni eutecticforms and lowers the melting point by765 K, the carbon available as a resultof the dissociation of SiC during laserjoining can, therefore, be dissolved intothe solution at a much lower
Figure 9: Free energy of formation as a function of temperature for SiC, TiC, and(1/3) AI.C,.
temperature. Furthermore, the interactionbetween Ti and C becomes much fasterand thus the rate of reaction increases.At present a parallel investigation oflaser induced reaction joining of SiCparticulate / AI-alloy composite usingTi-Ni (alloy or powder mixture) as aninterfacial reactive filler material isbeing conducted. The effect of Ti-Ni onthe joint structure and mechanicalproperties is being evaluated and will bediscussed in a future publication.
5.0 Summary
A proof of concept of LaserInduced Liquid Phase ReactionSynthesis Assisted Joining using Ti asan interfacial reactive filler material issuccessfully demonstrated. The processcompletely prevented the formation ofplate-like aluminum carbide structures,which are deleterious to mechanical andcorrosion properties of joints. Thetechnique used a laser beam to bothsynthesize the interfacial reactant
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rCa)
rAl-Ti~ \IPhase~
~"
\
• \
______-------...l [35_ p~,~
12000. (b) AI10000.
8000.III
~ 6000.0u
4000.Ti
2000. f- Si A~Ti0
II\,0 t 2. 3. 4. 5. 6.
KeV
Figure 10: Existence of AI-Ti phase in fusion zone of the laser induced reaction joined10 vol% SiC/AI composite. (Delivered power 2100 watts). (a)Microstructure of AITi phase and, (b) EDS spectrum showing elementalanalysis of the phase.
material and to heat the base compositematerial adjacent to the joint region tominimize the thermal stresses. The laserenergy along with Ti as an interfacialreactive material produced severalphases such as AI3(Si,Ti}z, AI6(Si,Ti),
AITi, AI2SiC2, (AI,Si)C which areexpected to enhance the wettingcharacteristics of the base material andthereby the strength of the joint.Accordingly, the authors are presentlyinvolved in conducting the efforts tostudy these effects and will be a topic ofdiscussion for future publication.
6.0 References
I. Rohatgi, P. K., R. Asthana, and S.Das, International Metals Review,VoI.3I, No.3. p.1I5, (1986).
2. Stedfeld, R., R. H. Wehrenberg, andW. K. Kinner, MaterialsEngineering, p.24, January (1980).
3. Divecha, A. P., and S. G. Fishman,Society for the Advancement ofMaterials and Process EngineeringQuarterly, pAO, April (1980).
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4. Divecha, A. P., S. G. Fishman, andS. D. Karmarkar, Journal of Metals,Vo1.33, No.9, p.12, (1981).
5. Maclean, B. J. and M.S. Mishra,Mechanical Behavior of MetalMatrix Composites, J.E. Hack, andM.F. Amateau, eds.,TheMetallurgical Society of AmericanInstitute of Mining, Metallurgicaland Petroleum Engineers, p.301,(1982).
6. Raviprakash, K. S., and E. S.Dwarkadasa, Journal of Metals,Vo1.39, No.5, p.28, (1987).
8. Brochure: DURALCAN USA,Division of Alcan AluminumCorporation, San Diego, California.
9. Ellis, D. S. and D. L. McDanels,Metallurgical Transactions A,Vo1.24A, No.1, pA3, (1993).
10. Devincent, S. M., and G. M. Michal,Metallurgical Transactions A,Vo1.24A, No.1, p.53, (1993).
11. Kuniya, K., H. Arakawa, T. Kanai,and T. Yasuda, Institute of Electricaland Electronic EngineersTransactions on Components,Hybrids, and ManufacturingTechnology, VoI.CHMT6, NoA,pA67, (1983).
12. Thaw, C, R. Minet, J. Zemany, andC. Zweben, Society for theAdvancement of Material and
464
Process Engineering Journal, Vol.23, No.6, pAO, (1987).
13. Schmidt K. A., and C. Zweben, inElectronic Materials HandbookVolume 1: Packaging, AmericanSociety for Metals International,Materials Park, Ohio, p.1127,(1989).
14. Zweben, C., The Journal of theMinerals, Metals and MaterialsSociety, Vo1.44, No.7, p.I5, (1992).
IS. Premkumar, M. K., W. H. Hunt, Jr.,and R. R. Sawtell, The Journal ofthe Minerals, Metals and MaterialsSociety, Vo1.44, No.7, p.24, (1992).
16. Schaefer, W. H., and J. L. Christian,Report AFML-TR-69-36, Vol. I, II,III, (1969).
17. Kennedy, J. R., Welding ResearchSupplement, p.250, May (1972).
18. Goddard, D. M., R. T. Pepper, J. W.Upp, and E. G. Kendall, WeldingResearch Supplement, p.178, (1972).
19. Swazey, E. H., and W. F.Wennhold, Report AFML-TR-72108, Parts I and II, (1972).
20. Miller, M. F., J. L. Christian, W. F.Wennhold, and E. E. Spier, ReportGDCA-DBG-73-006, ContractNAS8-77738, (1973).
21. Hersh, M. S., WeldingJournal,VoI.50, p.515, (1971).
22. Reynolds, G. H., and L. Yang,
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GDCA-DBG-73-006, ContractNAS8-77738, (1973).
of Laser Applications, Vo1.3, No.3,p.35, (1991).
36. Stoems, E. K., The RefractoryCarbides, Academic Press, NewYork, (1967).
33. Schoenhahl, J., B. Willer, and M.Daire, Journal of Materials Science,VolA, p.338, (1979).
31. Arsenault, R. J., and C. S. Pande,Scripta Metallurgica et Materialia,Vo1.l8, p.1131, (1984).
32. Iseki, T., T. Kamada, and T.Maruyama, Journal of MaterialsScience, V01.19, p.1692, (1984).
T. Ya., Carbides:Production and
Plenum Press, New
34. Bhushan, B., and B. K. Gupta,Handbook of Tribology: Materials,Coating and Surface Treatment,McGraw Hill, Inc., New York,(1991).
37. Kang, S., E. M. Dunn, J. H.Selverian, and H. J. Kim, CeramicBulietin,Vol.68, No.9, p.1608,(1989).
30. Dahotre, N. B., M. H. McCay, T. D.McCay, S. Gopinathan, and C. M.Sharp in Machining of Composites,T.S. Srivatsan and D. Bowden, eds.,American Society for MaterialsInternational, Materials Park, Ohio,p.167, (1992).
28. Dahotre, N. B., S. Gopinathan, M.H. McCay, T. D. McCay, and C. M.Sharp, Light Weight Alloys forAerospace Applications 11, E.W. Leeand N.J. Kim, eds., The Minerals,Metals & Materials Society,Warrendale, PA, p.313, (1991).
27. Dahotre, N. 8., M. H. McCay, T. D.McCay, S. Gopinathan, and L. F.Allard, Journal of MaterialsResearch, Vo1.6, No.3, p.514,(1991).
25. Devletian, J. M., Welding Journal,p.33, (1987).
24. Aheam, J. S., and C. Cooke, MMLTR-82-15C, Martin Marietta Lab.,Baltimore, MD, (1982).
26. Dahotre, N. B., T. D. McCay, andM. H. McCay, Journal of AppliedPhysics, Vo1.65, No.12, p.5072,(1989).
23. Aheam, J. S., C. Cooke, and S. G.Fishman, Metals Construction,Vo1.l4, NoA, p.192, (1982).
22. Reynolds, G. H., and L. Yang,Report ARO 22817-5-MS-S, (1987).
21. Hersh, M. S., WeldingJournal,Vo1.50, p.515, (1971).
29. McCay, M. H., T. D. McCay, N. B.Dahotre, and C. M. Sharp, Journal
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Dahotre, McCay, and McCay
38. McGuire, J. C., Review ScientificInstruments, Vo1.29, No.9, p.893,(1955).
39. Yokokawa, H., N. Sakai, T.Kawada, and M. Dokiya,MetaJlurgical Transactions A,Vo1.22A. No.12, p.3075, (1991).
40. Fine, M. E., and J. G. Conley,Metallurgical Transactions A,Vo1.22A, No.9, p.2609, (1990).
