D. Huda1993 Highlte

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Jour na l o f Mate r i a ls P rocess ing Techno logy,37 (1993) 513 528 513Elsevier

Metal-matrix composites: Manufacturingaspects. Part I

D. Huda , M.A. E1 Baradie and M.S. J . Hashmi

Ad van ced Mate r i a l s P rocess ing Cen tre, Schoo l o f Mechan ica l and M anufac tu r ingEng inee r ing , D ub l in C i ty Unive r si ty, Du b l in 9 , I r e l and

I n d u s t r i a l S u m m a r y

In recent years the potential of metal-matrix composite (MMC) materials for significantimprovement in performance over conventional alloys has been recognised widely. However,their manufacturing costs are still relatively high.

This paper (Part I) surveys and outlines the different manufacturing routes employedcurrently in the production of MMC.

An economic assessment of each route is discussed together with the selection of the mosteconomic route for a particular application.

Part II surveys and outlines the properties of matrix/reinforcement materials and dis-

cusses the procedure of selecting the proper matrix/reinforcement materials combination.

1 . I n t r o d u c t i o n

Metal-matrix composite (MMC) materials are currently experiencing act ivedevelop ment in the USA, Jap an and Europe. The benefi t of using MMCmater ia ls i s in the adva ntage of a t ta in ing proper ty combinat ions tha t canresult in a number of service benefits. A mong these are increa sed strength,decreased weight , higher service temperature, improved wear resistance,higher elast ic modulus and improved wear resistance.

The excellent mechan ical propert ies of these materials , toge ther with theweight saving and the relat ive low cost in production, makes them veryattra ct ive for a variety of engine ering applica t ions in the automot ive andaerospace industr ies . This paper surveys and outl ines the different manufac-turin g routes employed curren tly in the produc tion of MMC.

There are several fabricat ion techniques available to manufacture the MMCmateria ls: th ere is no uniqu e ro ute in this respect. Due to the choice of mate rial

Correspondence to:M.S.J. Hashmi, School of Mechanical and Manufacturing Engineering, DublinCity University, Dublin 9, Ireland.

0924-0136/93/$06,00 ~(? 1993 Elsevier Science Publishers B.V. All rights reserved.


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514 D. Huda e t a l . /MMCs: Manufactur ing aspects . I

and reinforcement and of the types of reinforcement, the fabrication techniques can v ary considerably. Generally there are two types of fabricationmethods:

(1) Solid-phase fabrication methods: diffusion bonding, hot rolling, extrusion, drawing, explosive welding, PM route, pneumatic impaction, etc.

(2) Liquid-phase fabric atio n methods: liquid-metal infiltratio n, squeeze cast-ing, compocasting, pressure casting, spray codeposition, etc.

Normally the liquid-phase fabrication method is more efficient [11 thanthe solid-phase fabrication method because solid-phase processing requiresa longer time.

The matrix metal is used in various forms in different fabrication methods.Generally powder is used in pneumatic impactio n and the powder metallu rgytechnique, and a liquid matrix is used in liquid-metal infiltration, plasma

spray, spray casting, squeeze casting, pressure casting, g ravi ty casting, compo-casting, inv estm ent casting, etc. A mole cula r form of the ma trix is used inelectroforming, vapour deposition (cvd, pvd, and electrodeposition) and metalfoils are used in diffusio n bonding, rolling, extrusio n, etc.

There are currently six manufacturing processes that have reached indus-trial status: these are diffusion bonding, the powder metal lurgy route, liquid-metal infiltration, squeeze casting, spray co-deposition and compocasting.

These six methods will be discussed in this paper, as they are competing toproduce the lowest cost material with the best mechanical properties.

2. S o l i d - p h a s e f a b r ic a t i o n m e t h o d s

There are several ways to fabricate MMC using solid-phase materials butamong them diffusion bonding and the powder metallurgy route are usedwidely.

2 . 1 . D i f f u s i o n b o n d i n gThis method is normally used to manufacture fibre reinforced MMC with

sheets or foils of matrix material. Figure 1 [2] shows the different steps infabricatin g MMC by diffusion bonding. Here primarily the metal or metalalloys in the form of sheets and the rein forc emen t mate rial in the form of fibreare chemically surface treated for the effectiveness of interdiffusion. Thenfibres are placed on the metal foil in pre-determined orientation and bondingtakes place by press forming directly, as shown by the dotted line. However~sometimes the fibres are coated by plasma spraying or ion plating for enhanc-ing the bon ding st ren gth before diffusion bonding: this is shown by the solidline. After bonding, secondary machining work is carried out. Again themethods of putti ng t ogethe r reinforce ment fibres and matrix mate rials dependupon the fibre types. In the case of monofil aments and fibre bundles such as C,SiC/W, SiC and A1203, th ey are wou nd on to a drum o f a metal h avi ng goodthermal conduction (Cu, for instance). Then the preform materials of com-posites are made by applying the matrix material on reinforcements through


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D. Huda et al./MMCs: Manufacturing aspects. I 515

S u r f a c e t r e a tm e n t

S t a r t i n g m a t e r i a l

I M o n o f i l a m e n t

B u n d l e [

S u r f a c e t r e a t l n e / l t I

P l a s m a s p r a y in g

W i n d i n gI

I o n p l a t i n g

C u t t i n g o f p r e f o r n a e d m a t e r i a l

A s s e m b l y o f p r e f o r m e d m a t e r i a l

F a b r i c a t i o n (d i f f u s i o n b o n d i n g ) . . . .

H e a t t r e a tm e n t

S e m i - p r o d u c t :sheet , s t r ip ,ere t C h e c k

V

M a c h i n i n g [

J o i n i n g p a r t s

C om posite om ponents ]~ IF i l i a l c h e c k

Fig. 1. Flow chart for composite fabrication by diffusion bonding [2].

various coating methods such as plasma spraying, chemical coating, electro-chemical plating, cvd and pvd coating. Among these coating methods, plasmaspraying [2] is a relatively simple technique of low cost which can producesheets of large width with good adhesion between the fibre and matrix. Thenthe preform is press formed, achievin g bonding of fibre and ma trix thr oug h t heapplication of pressure and temperatu re eit her by hot pressing or cold isostaticpressing, to enhance the density of the composite by removing voids andimprove the strength of the composite by the introduction of some plastic

deformation in the metal matrix. Diffusion bonding under vacuum co ndition ismore effective tha n unde r atmos pheric c ondit ions [3-5]. Because of the rela-tively low temperatures involved, a fibre coating treatment for solid-phase


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516 D. Huda et al./MMCs: Manuf acturing aspects. 1

fabri cati on is not critical as it is in the case of liquid-metal infiltration , but thepressure applied for enha nci ng diffusion bondi ng may cause damage [7 10].The applied pressure and temperature as well as their durations for diffusionbonding to develop, vary with the composite systems. Normally filaments ofstainless steel, boron and silicon carbide have been used with matrices such asalu mini um and t it ani um alloys [11 14]. However, this is the most expensivemethod of fabr icat ing MMC mat eria ls [15 16].

2.2. The powder metallurgy techniqueThe PM route is the most commonly used method for the preparatitm oi

dis con tin uou s reinforced MMC s [17 22]. Several companies are using this:technique to manufacture MMC using either particulates or whiskers as t;bereinforcement materials. Among them DWA. Silag and Novamet are wellkno wn lead ing MMCs. Figu re 2 shows the flow cha rt of the general powder

WHISKERS ORPARTICULATE

POWDER* Metal orMetal Alloy

\ /I BLENDING

J

COLD PRESSING ]

l

\\

-a

HOT PRESSING

EXTRUSION

I

~jBILLET,SLAB"l* consolidate

I R O L L IN O V F O R O 1N O[ - - I

F i g . 2 . F l o w c h a r t f o r c o m p o m t e f a b r i c a t i o n b y p o w d e r m e t a l l u rg y.


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D . H u d a e t a l . /M M C s : M a n u f a c t u r i n g a s pe c ts . I 517

met all urg y route. In this process powders of matri x mater ials a nd reinforce-ment are first blended and fed into a mould of the desired shape. Pressureis then applied to further compact the powder (cold pressing). In order

to facilitate the bonding between the powder particles, the compact isthen heated to a temperature that is below the melting point but suffi-ciently high to develop significant solid-state diffusion (sintering). Alter-natively, after blending the mixture can be pressed directly by hot pressing:however HIP is helpful for securing high density material. The consolidatedproduct is then used as a MMC material after some secondary operation.DWA and Silag use the proprietary blending process to combine reinforce-ment with metal powder whereas Novamet employes the mechanical-alloying techniques to combine the reinforcement and matrix constituents.Metallic materials such as copper, nickel, aluminium, cobalt, titanium,

molybdenum-based alloy and steel are o ften used in the powder processas matrix materials [11] with reinforcing elements SiC, graphite, Ni, Ti andMo [23-24]. Sin ce no melti ng and cast ing is involved, the powder processis more economical than many other fabrication techniques. This techniqueoffers several advantages over fusion metallurgy of diffusion bonding[25], some of these advantages being as follows.

(1) Lower tempera ture can be used during pre parat ion of a PM-based com-posite compared to the preparation of a fusion metallurgy based composite.This results in less interaction between the matrix and the reinforcement,consequently minimising undesirable interfacial reactions, which leads toimproved mechanical properties.

(2) In some cases PM tech nique s will permit the p repa rati on of compositesth at can not be prepared by fusion metall urgy. It has been reported [26] th at SiCwhiskers will dissolve in a molten Ti-alloy matrix, while dissolution can beminimized by using the PM route. Again it has been shown t ha t SiC fibres arehighly compatible with solid aluminium but only fairly compatible with liquidaluminium [27].

(3) The preparation of particulate- or whisker-reinforced composites isgenerally speaking easier using the PM blending technique t han it is using thecasting technique.

(4) Particulate reinforcement is much less expensive than continuous fila-ment of similar composition.

This method is popula r because it is reliable compared with other alt erna tiv emethods, but it has also some demerits. The blendin g step is a time consuming,expensive and potentially dangerous operation. In addition, it is difficult toachieve an even distribution of particu late th roug hou t the product and the useof powders requires a high level of cleanliness, otherwise inclusions will beincorporated into the product with a deleterious effect on fracture toughness,fatigue life, etc.


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518 D. Huda et a l . /MMCs: Manufactur ing aspects , l

3. L i q u i d - p h a s e fa b r i c a t i o n m e t h o d s

Four kinds of liquid-phase fabrication methods: liquid-metal infiltratmn.squeeze casting, spray codeposition and compocasting; are described here inthe manner in which they are used currently.

3 .1 . L i q u i d - m e t a l in f i l t r a t i o nThis pro cess ca n also be called fibre-tow inf ilt rat ion . Fibres to ws can b~-"

infi ltra ted by passing th rou gh a bath of molte n metal [28 31]. Usua lly the fibresmust be coated in line to promote wetting. Once the infiltrated wires areproduced, they must be assembled into a preform and given a secondaryconsolidation process to produce a component. Secondary consolidation i~

generally accomplished through diffusion bonding or hot moulding in thetwo-phase liquid and solid region.

The fabrication process of MMC by vacuum metal infiltration used byCha pman et al. [32] is shown in Fig. 3. These a uth ors used alum ini um oxidefibre FP (pol ycrys talli ne fibre) of Du Pon t Company. In this techniq ue, as thefirst step, FP yarn is made into a handleable FP tape with a fugitive organicbinder in a man ne r similar to producin g a resin matr ix composite prepeg. FibreFP tapes are then laid-up in the desired orientation, fibre volume loading, andshape, and are then inserted into a casting mold of steel or other suitablematerial. The fugitive organic binder is burned away, and the mold is infiltrated with molten metal and allowed to solidify. Metals such as aluminium~magnesium, silver and copper have been used as the matrix materials in thisliquid infiltrati on process because of their relatively lower melting points. Thismethod is desirable in producing relatively small-size composite specimenshavin g unidi recti onal properties [11].

The ap plication of this process is limited because of the wett ability problemof reinforcements with all liquid metals and deg radati on of many fibres at hightemperatures. For example, at liquid-metal temperatures, boron filaments arestable only in str uctu ral grade magnesium [33].

The infiltrat ion process can be done under atmosphe ric pressure, in inert gaspressure a nd in vacuum. Among these, vac uum in filt rati on is the best way [32]to fabricate MMC because in vacuum the surface activity of fibres is higherand thus better wettability can be achieved. Metal-matrix composites of thetypes AlzO3 whisker reinforced A1, Gr/A1, B/Mg and C/Mg have been fab-rica ted by this te chn iqu e [34-35]. Yang [36] has su ccessfully used this v acu uminfiltration technique to fabricate 3D braided A1203 preform reinforced AI-Limatrix composites. To date, the versatility of this approach has been demon-strated by preparing fibre FP reinforced aluminium, Mg, lead, Cu and zinccomposites [32]. The fibre FP/ al umi ni um casti ng i nfil trat ion process differsfrom the liquid-infiltration process used for preparing graphite/aluminiumcomposites because the FP/metal fabrication process permits casting of com-plete parts in a single infiltration step [32].


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D. Huda et a l . /MMCs: Manufactur ing aspects . I 519

F I B ER F P P R E PA R AT I O N

lP R E PA R E F I B ER F P TA P E* F l e x i b l e , f u g i t i v e b i n d e r

P R E - F O R M O R C O N S O L I D AT EF P TA P E* Vo l u m e l o a d i n g* O r i e n t a t i o n

lL O A D F P P R E F O R M LI N T O M O L D F

B U R N O F F B I N D E R* C o n v e n t i o n a l h e a t i n g

to 500 *C wi th a i rp u rg e t h r u F P p r e f o r m

I M O L D P R E PA R AT I O N

A P P LY WA S H C O AT T OI N T E R N A L S U R F A C E SO F M O L D

C O M P L E T E M O L D A S S E M B LY* I n s t a l l g a t e s y s t e m* Va c u u m s e a l m o l d

1[ P R E " E A T C A S T IN O I

M O L D A S SE M B LY I

Fig. 3. Flow chart for FP/A1 plate castings [32].

A L - L I A L L O Y IP R E P A R AT I O N

A L - 2 . 0 W T % IL 1 A L L O Y [* C o n v e n t i o n a l f o u n d r y

m e l t i n g w i t h f l u x I

I

I N F I LT R AT E F P I

IR E F O R M

,LJ S O L I D I F Y

3 .2 . S q u e e z e c a s t i n gMost reinf orce ment materials such as graphite, silicon carbide, alumina and

stainless steel fibres [37] do not wet prop erly in molten met als and t her efo re itis difficult to fabricate composites by infiltration. In contrast, in the squeezecasting technique, the molte n metal will be force-infiltrated into the fibrebundles (preforms), expelling all absorbed and trapped gases.

Squeeze casting is defined as the ability to forcibly charge liquid metal into

a pre-heated ceramic fibre or any reinf orcem ent preform that is set in a metaldie and then to allow the liquid metal to solidify whilst applying a highpressure, ther eby squeezing the liquid metal. The f abricat ion process of MMC


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520 D. Huda et al./MMCs: Manufacturing aspects. I

by squeeze cas ting due to Fu ku na ga [38] is shown in Fig. 4. The preform of theceramic fibre is pre-heated to several hundred degrees Centigrade below themelting temperature of the matrix and then set into a metal die. The AI or Mgalloy is heated to just above its melting temp erature and is then squeezed intothe fibre preform by a hydraulic press to form a mixture of fibre and moltet~metal. F igure 5 shows a prefo rming metho d by pressing [38]. After mixing theshort fibre homogeneously with water, the slurry is poured into t he mould, anddewatering is conducted during forming. The objective of this step in theprocess is to give a homogeneous distribut ion of the fibres and enough strengt hto the preform to avoid diso rdering of the fibres durin g the process of infiltra-tion by the molten metal.

This process is employed solely fbr the benefits of high prod ucti vity and easyformability . The composites produced are of good qualit y and hig h and reliable

stren gth is attaina ble by controlli ng the process parameters and by optimizingthe microstructureo Since the solidificat ion times become very short whenusing a hi gh press ure (70-100 MPa) for squeezing the liquid metal, ther e is noreactio n zone developed on the inte rface of the m atrix and the reinforcemenLgiving a void-free and high-strength composite. It is generally applicable

Fiber p r e f o r m/

PLa~

D i e 1/

/ P

' v ~ _ C o s N n g w d h M N C

a) b) c) d)

Fig. 4. Sequences of the squeeze-casting process with a vertical machine [38]: (a) pouring;(b) casting; (c) squeezing; and (d) ejecting.

Agi t a to r ~ P i s ton

I / I U U 1 ,,,J I U L l l Ji i,,,I,i

S l u r r y F i l t e r W a t e r Fiber P r e f o r m

a) b) c ) d )

Fig. 5. Fabrication process of a fibre preform by press-forming [38]: (a) agitating; (b) molding:(c) squeezing; and (d) drying.


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D. Huda e t a l . /MMCs: Manufactur ing aspects . I 521

to fabric ate composites using all types of reinforcemen t. A1203/A1, C/Mg,SiCw/A1, Si3N4w/A1 comp osit es are fab rica ted easil y by this me th od [39-40]. Ingeneral, squeeze-cast materials have a highe r stren gth tha n t hat of the same

mater ials cast u nder gravi ty [41 43]. Bha gat [44] fabricat ed stainless steel wirereinforced alum iniu m matrix composites by high-pressure squeeze-casting andshowed that these composites at a 40% fibre volume fraction have a tensilestrengt h tha t is more tha n three times greater than t hat of an alumin iummatrix cast under the same fabrication conditions.

This process can be used for large scale manu fac tu rin g but it requires carefulcontrol of the process variables, including the fibre and liquid metal preheattemperature, the metal alloying elements, external cooling, the melt quality,the tooling temperature, the time lag between die closure and pressurization,the pressure levels and duration and the plunger speed. Imperfect control of

these process variables results in various defects, including freeze chocking,preform deformation, fibre degradation, oxide inclusions and other commoncasting defects.

In this process, a majo r limi tati on is the size of parts th at may be castbecause of the high-pressure requirements. Ano the r limita tion lies in the rangeof shapes t hat can be cast. However, in pract ical use, squeeze casti ng is themost effective method of constructing a m/c part with a complex shape ina sho rt time [45]. Hid ehar u and koichi [46] fabricat ed composites of siliconcarbide fibre reinforced A1 and Mg metals by this process and showed theexistence of eutectic surroundin gs th at are inde pendent of the squeeze pres-sure but depend on the alloy quantity and on the fibres, which lowered thetensile strength of the composite.

3 .3 . S p r a y c o - d e p o s i t i o nThis is an eco nomical method of producin g a parti cul ate composite using the

spray-deposition method.Alcan has installed laboratory-scale deposition units at its Banbu ry Labor-

atories to i nvestigate the possibilities of manu fact urin g MMCs on an economicscale, con cen trat ed prima rily on SiC as the reinforci ng element. A schemat ic ofthe Alc an spray deposition process is shown in Fig. 6. The alloy to be sprayed ismelted in a crucible by induction heating. The crucible is pressurized and themetal is ejected through a nozzle into an atomizer where at the same timeparticles (reinforcement) are injected into the atomized metal and deposited ona pre-heated subst rate placed in the line of flight. A solid deposit is built up onthe collector. The deposited strip, when cold, is moved from the sub strat e forsubsequent rolling. The shape of the final product depends on the atomizingcond itio n and the shape and the mot ion of the collector. The equipment can bemodified simply to produce hollow tube, near-net-shape forging stock, extru-sion ingots or plate [47].

Singer and Ozbek [48] formulated a squeeze-casting technique to manufac-ture a composite. They used various second-phase particles, namely sand,alu mina , SiC, chille d iron, gra phi te etc. Up to 36% o f SiC, A1203, chill ed iron,


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52 2 D . H u d a e t a l . / M M C s : M a n u f a c t u r i n g a s pe c ts . I

furnoce

0 r ! ' I

t hreinfocced ~ . \ / I

collect Y

~ / / / / / / / / , r , / . r / / / / / / / /

floor

F i g . 6. S c h e m a t i c o f s p r a y d e p o s i t i o n e q u ip m e n t .

graphite and sand particles and a mixture of these, 75- 120 ~m in size, can beincorpo rated successfully in alumin ium and AI 5Si alloy matrices. Struc turalexamination showed that a homogeneous distribution of particles is obtainedeven with mixtures of particles having widely differing morphology and den-sity, moreover the particles were surro unded completely by the matrix mater-ial. No significant diffusion was observed across the particle/ma trix in terfacesbecause of the very short matrix solidification time.

White a nd Willis [17] used the squeeze-casting techn iqu e to man ufa ctu re SiCreinforc ed A1 composites. This route for MMC pr oduc tio n has a dva ntag es overthe competitive routes in terms of both the mi crostructure, the properties andthe efficiency of the process and it can be used for the produ ction of largequan titie s of high q uality M MCs in both a technologica l and economical sense.It can be used to produce materia ls which have applications includin g frictionmaterials, electrical brushes and contacts, and cuttin g or grinding tools [48].Full density is not achieved during this process and hot- or cold-rolling areused to densify the material prior to mechanical testing [25]. Billets of MMCmater ial, m easu ring up to 250 mm diameter, are alre ady av ailabl e commer-cially from the British Alcan company, which has developed the technique.

There is another process, namely the Osprey process, developed by Evans.Leatham and Brooks [49] which is a derivative of Singer's [48] spray-casting

process, that apparently is able to produce high-density spray-cast preforms.This is accomplished by careful control of several spray-casting process para-meters, that include melt superheat, substrate he ati ng and the amo unt of heat


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D. Huda et al./MMCs: Manufacturing aspects. I 523

removed from the melt durin g a tomi zatio n [25]: however, no more workon the preparation of composite materials by the Osprey process isavailable [50].

3.4. CompocastingOther than PM, thermal spraying, diffusion bonding and high-pressure

squeeze casting, this is the most economical method [37,51] of fabricatinga composite with di scon tinu ous fibres (chopped fibre, whiske r and particula te).This process is the improved process o f slush- or stir-casting.

A schemat ic of the co mpocasting equipme nt used to fabric ate the compositesis shown in Fig. 7, as used by Hoski ng et al. [52]. The ap pa rat us consist s of anin du cti on power suppl y (50 kW, 3000 Hz), a water-co oled vacu um ch ambe r wit h

O C m o t o rA

' ' ' "n. . l , , . .. , 0 . , 0 o ,,

s h a f t a n d b l a d eassembly

b e a r i n g

i f eede r _ .~power t r o u g hcables

l e t

o u t l e t

w a t e r cooled .......4Pg r a p h i t emould

~ t h e r m o c o u p l e

w a t e rc o o l e di n d u c t i o n

~ c o i l s

motor and

feeder

control

w a t e r c o o l e d

s t a in l e s s -s t ee lA c h a m b e r

s t a n d

Fig. 7. Compocasting: (a) mixing fibres (or particulates) with metal; followed by (b) diecasting [52].


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524 D . H u d a e t a l . / M M C s : M a n u f a c t u r i n g a s pe c ts . I

movabledie-half

liquid

ring insert ~ ~stationaryT lower d~e

ejectorp i n movable~ ' ~ . J 4 " " " ~ d , e - ha ,

liquid ""-"--.--.-..~-..,~" ox,decomposite ~ / ~ part+cles

r / / / / / / / / , d V / / / . / / / / Jd" . .~c r a m , c

I J t ' " " '/~ \ s ta t ,onary

elector p i n tower die

WFig. 7. (Continued).

its associated mechanical and diffusion pumps and a crucible and mixingassembly for agitation of the composites.

First, a metal alloy is placed in the system with the blade assembly in place.Then the chamber is evacuated and the alloy is superheated above its meltingtemperature and stirring is initiated by the DC motor to homogenize thetemperature. The induction power is lowered gradually until the alloy is 40 to50% solid, at which point the non-metallic particles are added to the slurry,However, the temperature is raised during adding in such a way that the total

amo unt of solid, whic h consi sts of fibres and solid globules of the s lurry, doesnot exceed 50%. Stirr ing is continued unti l interface interact ion s between thepart iculat es and the matrix promote wett ing. The melt is then superheated to


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D . H u d a e t a l . / M M C s : M a n u f a c t u r i n g a s p e ct s . I 5 2 5

[ . .

C

. = .

o

i0

rm

. = , ~ ~ ~ ~ ~ o

_ ~ > o o ~ I

= o ~ ~

,.~ ,.o ~ ~ " ~

o . . o ~

, ~ . ~ o

e,

9 (D

Em

~ ' B ~

I


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526 D. Huda et al./MMCs: Manuf acturing aspects. I

a b o v e it s l iq u i d u s t e m p e r a t u r e a n d b o t t o m p o u r e d i n t o t h e g r a p h i t e m o u l d b yr a i s i n g t h e b l a d e a s s e m b l y.

T h e m e l t c o n t a i n i n g t h e n o n - m e t a l l i c p a r t i c l e s is t h e n t r a n s f e r r e d i n to t h el o w e r d i e - h a l f o f t h e p r e s s a n d t h e t o p d i e is b r o u g h t d o w n t o s h a p e a n d s o l i d if )t h e c o m p o s i t e b y a p p l y i n g t h e p r e s s u r e a s i n d i c a t e d i n F ig . 7 (b ), u s i n g f o r t h ec o m p o s i t e t h e h i g h e s t v a l u e s o f v o l u m e f r a c t i o n s o f r e in f o r c e m e n t~

T h e p r o c e s s h a s s e v e r a l a d v a n t a g e s [15]:(1) It c a n b e p e r f o r m e d a t t e m p e r a t u r e s l o w e r t h a n t h o s e w h i c h a r e ~lsed

c o n v e n t i o n a l l y in f o u n d r y p r a c t i c e d u r i n g p o u r i n g , r e s u l t i n g i n r e d u c e dt h e r m o - c h e m i c a l d e g r a d a t i o n o f t h e r e i n f o r c e m e n t s u r fa c e .

(2 ) T h e m a t e r i a l e x h i b i t s t h i x o t r o p i c b e h a v i o u r , t y p i c a l o f s t i r c a s t a l l o y s : i~t h e r e f o r e o f f e rs n e a r - n e t s h a p e f o r m i n g a t l o w p r e s s u r e i n th e s e m i -s o l id s ta te ~r e s u l t i n g i n a d e f e c t - f r e e p r o d u c t .

(3) P r o d u c t i o n c a n b e c a r r i e d o u t by c o n v e n t i o n a l f o u n d r y m e t h o d sH o w e v e r , t h e p r o c e s s h a s a l s o s o m e d i s a d v a n t a g e s :(1 ) R e s i d u a l p o r e s b e t w e e n f ib r es c a n n o t b e e l i m i n a t e d c o m p l e t e l y(2 ) S l u r r y i s a p t t o fa l l o f f o n h a n d l i n g a n d t h e p r o c e s s c a n n o t h a n d l e f ib r e

f o r f a b r i c a t i n g f i b r e -r e i n f o rc e d c o m p o s i te .I n a s s o c i a t i o n w i t h t h e D u r a l c a n c o m p a n y , m a n y r e s e a r c h e r s h a v e u s e d t h is

t e c h n i q u e to m a n u f a c t u r e d i s c o n t i n u o u s r e i n f o r c e d a l u m i n i u m m a t r i x c om -p o s i t e ( A M C ) [15 , 2 7, 5 1 - 5 7 ]. A b i s [1 5] a n d K o h a r a [27 ] u s e d h o t p r e s s i n g a n dM i l l i e r e a n d S u e r y [57] u s e d s q u e e z e c a s t i n g a f t e r s t i rr i n g .

4 . C o n c l u s i o n s

A c o m p a r i s o n o f t h e d i f f e r e n t t e c h n i q u e s d i s c u s s e d i n t h i s p a p e r a r e g l w m 1:1~Ta b l e 1 . T h e c o m p a r i s o n is c a r r i e d o u t i n t e r m s o f c o s t, a p p l i c a t i o n a n d t h ep r o p e r t y p e o f r e i n f o r c e m e n t . F o r e x a m p l e , t h e c o s t o f u s i n g t h e c o m p o c a s t i n gt e c h n i q u e is r e l a t i v e l y l o w c o m p a r e d w i t h t h e c o s t o f u s i n g o t h e r t e c h n iq u e s ~s o t h a t t h e c o m p o c a s t i n g t e c h n i q u e i s w i d e l y u s e d in a u t o m o t i v e a n d a e r o s p a c ea p p l i c a t i o n s .

R e f e r e n c e s

[1] S. Kohara,Mater. Manufact. Process., 5 (1990) 51.[2] T.W. Chou, A. Kelly and A. Okura,Composites, 16 (1985 ) 187.[3] J.T. M oore, D.V . W ilson and W .T. Rob erts,Mater. Sci. Eng., 48 (19 81) 107.[4] O. Watanabe,Proc. 1st Jpn. USSR Syrup. on Composite Mater., Moscow Unive~'sit~

press , 1979, p. 226.[5] J . Inagaki , Y. Terasawa, E. Nakata and A. Okura,Proc. 2nd Jpn. USSR Symp. o~

Composite Materials, 1980 , p. 37;Tetsu To Hagane, 65 (197 9) 1946.[6] I. Shota and O. Watanabe,J. Mater. Sci., 14 (197 9) 699.[7] M. Sakai , O. Watanabe and K. Watanabe,Trans. Jpn. Inst. Met., 43 (1979) 181.[8] M. Moss, W.R. Hoover and D.H. Schuster,Proc. Sagamore Army Mater. Res. Con/:, 21

(1978) 425.[9] J .F. Dowly, B.A. Webb an d W .C. Ha rr igan,SAMPE Symp., 24 (19 79) 1443.[10] R.T. Debsk i and D.R. Bee ler,SAMPE Symp., 24 (19 79) 1382.


15/16

D . H u d a e t a l . /M M C s : M a n u f a c t u r i n g a s pe c ts . I 527

[11] J.R. Vinson and T.W. Chou, Compos i t e Ma te r i a l s and The i r Use in S t ruc tu re s ,AppliedScience Publishers, London, 1975.

[12] K.M. Prewo and K.G. Kreider, Meta l l . Trans . , 3 (1972) 2201.[13] A.G. Metacalfe, in: L.J. Broutman and R.H. Krack (Eds.), Compos i t e Ma te r i a l s ,Vol. 4,

Academic Press, New York, 1974.[14] P.R. Smith, F.H. Froes and J.T. Cammett, in: J.E. Hack and M.F. Amateau (Eds.), TMS

of AIME, Warrendale, PA 1983, p. 143.[15] S. Abis, Compos . Sc i . Technol . ,35 (1989) 1.[16] J. Lock, Prof . Eng. , (April, 1990) 21.[17] J. White and T.C. Willis, Mate r. Des . , 10 (1989) 121.[18] B.S. Majumder, A.H. Yegneswaran and P.K. Rohatgi, Mater. Sc i . Eng. ,68 (1984) 85.[19] T.G. Nieh and D.J. Chellman, Scr. Meta l l . , 18 (1984) 925.[20] A.P. Divecha, S.G. Fishman and S.D. Karmarkar, J . Me t . , 9 (1981) 12.[21] M.Y. Wu and O.D. Sherby, Scr. Meta l l . , 18 (1984) 773.[22] F.A. Girot, J.M. Quenisset and R. Naslain, Compos . Sc i . Technol . ,30 (1987) 155.

[23] M. Taya and R.J. Arsenault, M e t a l M a t r i x C o m p o s it e s T h e r m o m e c h a n i c a l B e h a v i o u r,Pergamon Press, 1988.[24] H.J. Rack, T.R. Baruch and J.L. Cook, in: R. Hayashi, K. Kawata and S. Umekawa

(Eds.), Progres s i n Sc i ence and Eng inee r ing o f Compos i t e s ,(Proc. ICCM-4), JapanSociety for Compos. Mate r., Vol. 2, 1982, p. 1465.

[25] D.L. Erich, M e t . P o w d e r R e p . ,43 (June, 1988) 418.[26] P.R. Smith and F.H. Froes, J . Me t . , 36 (1984) 19.[27] S. Kohara and N. Muto, Recent advances in composites in the uni ted states and Japan ,

ASTP 864, 457.[28] W. Meyerer, D. Kizer, S. Paprocki and H. Paul, Proc . 19 78 In t . Conf . on C omposi te

M a t e r i a l s I C C M 2 ,AIME, Warrendale, PA p. 141.[29] W.C. Harrigan and R.H. Flowers, Fa i lu re Modes i n Compos i t e s i v,in: J.A. Cornie and

F.W. Crossman (Eds.), AIME, Warrendale, PA 1977, p. 319.[30] R.T. Pepper and R.A. Penty, J. Compos. , Mater. ,8 (1974) 29.[31] E.G. Kendall, in: K.G. Kreider (Ed.), Composite Materials, Vol. 4, Academic Press, NY,

[1974.[32] A.R. Champion, W.H. Krueger, H.S. Hartman and A.K. Dhingra, Proc. Int . Conf. on

Compos i t e Ma te r i a l s ,AIME, Warrendale, PA 1978, p. 883.[33] M.M. Schwartz, Compos i t e Ma te r i a l s Handbook ,McGraw Hill , New York, 1984, p. 4.122.[34] K.I. Paul tnoi, S.E. Sal ibekov, L.L. Svetlov and V.M. Chubarov, St ruc tu re and P rope r t i e s

o f Compos i t e Ma te r i a l s ,1979.[35] S.T. Mileiko and A. Kelly (Eds.), Ha ndbo ok of Composites,Vol. 4, Nether lands, 1983, p. 287.[36] J.M. Yang, Adv. Ma te r. Manuf . P roces s . ,3 (1988) 233.

[37] A. Mortensen, J.A. Cornie and M.C. Flemings, Mate r. Des . , 10 (1989) 46.[38] H. Fukunaga, Adv. Ma te r. Manuf . P roces s . ,4 (1988) 669.[39] T.W. Cl yne and M.G. Bader, in: W.C. Harr iga n, J. Strife a nd A.K. Dhingra (Eds.), Proc .

I C C M - 5 , TMS of AIME, Warrendale, PA 1985, p. 755.[40] H. Matsubara, Y. Nishida, M. Yamada, I. Shirayanagi and T. Imai, J . Mater. Sc i . Let t . ,

6 (1987) 1313.[41] M. Nomoto, H. Tokisue, K. Kato and K. Aoki, Jpn . In s t . L igh t Me t . ,30 (1980) 212.[42] Y. Kaneko et al., Foun dr. Trade J ., 148 (1980) 397.[43] R.F. Lynch et al., A F S T r a n s . , 83 (1975) 569.[44] R.B. Bhagat, Composi tes , 19 (1988) 393.[45] H. Fukunaga, S. Komatsu and Y. Kanoh, Bul l . JSME, 26 (1983) 1814.[46] H. Fukunaga and K. Goda, B u l l . J S M E , 28 (1985) 1.

[47] P.S. Grant, B.P. Bewlay, P.P. Maher and B. Canter, in: D.M.R. Taplin and D. Taylor(Eds.), A d v a n c e d E n g i n e e r i n g M a t e r i a l s ,(Proc. Sixth Irish Materials Forum, Dublin,Ireland), 1989, p. 153.


16/16

528 D. Huda et al./MMCs: Manuf actu ring aspects, l

[48] A.R.E. Singer and S. Ozbek, Powder Metall., 28 (1985) 72.[49] R.W. Evans, A.G. Leatham and R.G. Brooks, Powder Metall. 28 (1985) 13.[50] Aerospace materials for the year 2000, Eng. Mater. Des., (1988) 26.[51] P. Rohatgi, Adv. Mater. Process., 2 (1990) 39.

[52] F.M. Hosking, F.F. Portill o, R. Wund erl ine and R. Mehrabia n, J. Mater'. Sci.. 17 ( ~.q82~[477.

[53] R. Mehrabian, R.G. Riek and M.C. Flemings, Metall. Trans., 5 (1974) 1899.[54] A. Sato and R. Mehrabian, MetalI. Trans. B, 7 (1976) 239.[55] K.J. Bhansall and R. Mehrabian, J. Met., 34 (1982) 30.[56] C.G. Levi, G.J. Abbaschian and R. Mehrabian, Metall. Trans. A, 9 (1978) 697.[57] C. Milliere and M. Surey, Mater. Sci. Technol., 4 (1988) 41

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