CA2148251A1 - Metal matrix composite having enhanced toughness and method of making - Google Patents

Abstract

2148251 9410351 PCTABScor01 A metal matrix composite comprising a stack of alternate layers of unreinforced metal and discontinuously reinforced metal. In a preferred embodiment, the unreinforced metal is an aluminum alloy and the discontinuously reinforced metal is an aluminum alloy reinforced with silicon carbide particles. The metal matrix composite may be formed by the steps of: (a) providing a stack of layers unreinforced metal and discontinuously reinforced metal; and (b) applying sufficient heat and pressure to the stack to cause interlayer adhesion of the layers and thus form a laminated MMC. The stack of layers may be alternating layers of unreinforced metal and discontinuously reinforced metal. In a preferred embodiment the outer layers of the stack are an unreinforced aluminum alloy.

Description

WO 94/103~1 PCr/US93/10360 ~ ~ ~
i``" 21~8~,~31 . .

ME:TAL 2~TRIX COMPOSIT}3: ~VING ~a~NCED
TOUGElNESS AND MEl~OD OF ~KING 1-Thi3 in~rention relakes to m~tal ma'crix ~-CompoBites (MMC~) and th~ manufactur~ thereof.
Mor~ particularly, the in~entio:~ rQlates to ~:
m~thods or increaaing th~ ~racture tough~s~
metal m~trix t:ompoaite~ via th~ ~abr~catio~ o~
discontinuously rein~orcad laminata structure~
MQtal matrix co~?o:~teR ha~e received ~uch attention as a ~ean8 to produc~ products ha~ring improved prope~tie~. ~oweYer, while ' ~:
icant gai;l~ may be made~ with respect to F.
c~rtai~ prop~rtie~, aomati~e~s th~: are obtained at th~ ~xpen~e of other proper ie~. For example, 1D. the alumiIlum i~d~t~y ~t i~ k~ow~
that the y~leld str~gt:h a~d Modulus o l~
ela~3tic~ty o~ a~ alu~num alloy casl b~ i~cr~a,~d through 'ch~ u~ of di~co~.,l~uou~ r~ r~
add~tiD~s to ~o~ di~cos~t~nuou~31y ro~oreed 2 0 alta~i~um (DRA) ~matsrial~ 0~rerthel~s~
co;~ urate iD~ro~r~2nt i2~ frac:ture 'cough~s~
i~ not obtai~ed in ~uch ~MC~. ~o~ th~ rsa~o~ ~ ~-th~ i~ro~ ~t in other prop~istie~ ~ay be ~u~ iD: co~o~ent~ for wh~ch tough~s~
2~ i~,o~t~.
Thu~ it caa be ~en that ~ t would be of great adva~'cag~, p~rtiaularly i~ alu~au~

: .
SUB~TlT(l,l E SH~
- .. `.

WO94/10351 PCT/US93tlO360 2 ~ ~ 8 ~ 5 :~ t^;,.'' ~' ' - 2 - , alloys, if the yi~d ~trength, modulu~ of ela~t~c~ty and C~racture toUghnQ88 can be j impro~ad together. The pre~snt in~ention p~rmits thesQ prop~rties of a meta} alloy to be ,, e~ha~ced. That i~, the pres~nt i~e~tion pro~ides MMC8 having i~provements in msdulus Oc ela~ticity while maintaining or im~ro~ing frac~ura toughn~s.
The primAry ob~ect of th~ pre~ant i~ention iB to impro~e the tou~ess of a metal matrix composite. :
Another ob~ect of the pr~nt ~.
in~ent~on i8 to improve the fracture tough~e~
of a metal m~trix compo~ite without significantly decr~asing the yield ~tre~gth or modulu~ of ela~ticity.
Another ob~ect o~ the pre~t ~.
in~ntio~ i~ to i~prove the tough~e~a of a metal ;:~
matrix compo~it~ fo~med from alloys of alumi~u~, ::
titanium, steel or ~ombination~ ther~of.
Accordi~gly~ thera i~ di3clos~d a : metal matrix composite ~a~i~g i~proved ~ractur~ ,~
toughnes~. The m~tal m~tr~x ~om~o~it~ aompri~e~
a ~tack of alt~rnat~ lay~r~ o4 u~r~l~orced metal a~a disoo~tinuou~ly rei~orc~d metal. In a pr~ferred embodim~nt, tk~ u~r~in~orced ~tal : i~ ~n alumi~u~ alloy:a~d th~ di~o~ti~u~u~ly r~ orc~d ~tal ~ a~ aluminu~ alloy r~ orced w~th ~ilico~ c~r~id~ particl~
A ~cond ambodime~t of th~;i~e~t~on -~
i~ a ~ethod ~or pro~tdl~g a m~tal matrtx compo~it~ ha~ing ~mprov~d fractur~ tough~
Tha ~Qthod c~pri~es th~ ~t0p~ o~
pro~idtng a stack o~ layer~ o~ unr~inorced 35 m~tal a~d di~co~ti3uously rel~or~d ~0tal; and . .
(b) applyi~g:~u~fici~t pre~uræ to t~e ~tack to cau~e i~terlayes a~he~io~ of the lay~ a~d th~ :
.

. -S7~B~.TITU~ ~_ET

W094/103~1 PCT/US93/1~360 lr~
2~3 ~

~orm a làmi~ated NMC. The stack of layer~ ~ay be altarnating lay~r~ Qf unreinforced metal a~d di~co~tinuously reinfor~ed metal. It i8 ¦
preferred that the unrainforced alloy forms the outer layer~ o~ th~ lami~ate.
I~ a preferred embodi~eat/ th~ method :~.
~omprise~ the ~tep~ of: (a) pro~idi~g a ~tack of alternating layer~ of a~ unreinforced aluminum alloy a~d aluminum alloy rei~forced with ~ilicon carbide particula~e~; (b) heating the ~tack and (c) applyi~g su~ficient pre~sure to the ~tack to cau~e interlayer adhe~ion.
Afterwards, th~ stack may be solution heat treated and/or artificially aged. ~ a mo~t preferred embodiment, metal foil i6 placed between the layer ~o e~hance interl~yer adhesion.
Othar ~eatures of the pre~e~t ,~
invention will be fuxther de~crib~d or r~ndered obviou~ in the following related de~cription o~
the preferred emhodiment which i3 to b~
con~id~red tog~ther wlth the accomp~y~ng drawing~ w~r~i~ lika figur~8 r~fer to liks . :~
part~ ~nd further wherein: -Figura 1 i~ a photomicrograph of an -.-alumi~u~ alloy pro:duc~ ~ad~ in accorda~ce with the ~nvo~tion. Th~ laminate h~ b~n ~Q~t~d and ~llu~trato~ ~rack tip blunt~ng a~d ~t~rfac~ ;
d~l~l~atlon ~hic~ r~eul~ed ~rom imp~ct testi~g.
Figure 2 i8 aa illu~tratio~ of :~
laml~at~z of pr~ent in~ontion in th~ c~c~ ;
di~idar and crack arr~tor ori~nt~tio~A. ,-The ter~ "unrci~orc0d ~Qtal" i~ u~ed ~ :
~rei~ to re~r to m~tal~ ahd alloy~ contai~ing 35 le8~ than 5 Yol.% of ~on-~2talli~ addod `.
r~inforce~t ma~rial~ and pr~~r~bly 1~ t~an l ~ol.%. ~xamples of unr~infor~ed ~aSal . ~.

-SUBST1T~JT~ F~T -~

W~94/10351 PCT/US93/10360 i~cl~de aluminu~, titanium, ~agne~ium, iron, copper, zinc and alloy~ in which at least one of th~ss metal~ i~ the largest ~ingle component. ~ .
The term l'reinforced metal" and ' ~;
~xei~forcèd alloy" are u~ed interchangeably '~ ;
h~rei~ to refer to alloy~ containing more than 5 Yol.% of non-metallic added rainforc~ment material~. ~xamples of relnforced metals includ~ unreinforced m~tal to whicn fibers, -~.
whi~ker~, filaments, particles, ribbon, wire, flake, c~y~tal~, plat21et3 ~d oth~r no~- ;
metallic rein~orcement~ are intentionally addsd.
The tenm i~ not intanded to include metal~ which ..
contain only intermetallic~ except where the ~olume or type of such intermetallic~ proYide~
significantly i~crea~ed sla~:tic modulus. ~--The term "discontinuously reiaforced metal" and ~pecifically ~di~continuou~ly rei~forc~d aluminu~" (DRA) are u~ed ~:
20 ~nterchang~ably herein to refQr to meta}~ and .
alloys in which the morphology of the rei~forcement i~ dl~conti~uous, mos~ o:fte~ with a ratio of largest to smalle~t dimen~ion of les~
tha~ about t~ to ono. The ~erm i~ ~ot lntended ;~-25 to `include alloys rei~for~d with long fibers, ~ `~
rib~o~8, ox wh~er~ with a ratio o~ l~rg~t to 8~allo8t d~m~n~on o~ mor~ than about ts~ to on~
The term "compo~it~ u~ad h~re~ to .
refer to a ~at~rial i~ which two o~ moro con~tituQ~t8 aro combi~ed to r~ult i~ a material wh~ch has prope~tie3 ~ign~ic~tly ~ 1 -r- - ~
dl~erent ro~ ~thQr co~ituent. R~ orced mat~l, r~ orc~d alloy, di3conti~uously rei~or~ed ~tal and di~co~tinuously rGi~orced alu~i~um are exampl~ o~ mstal matrix co~po~it~s. Typlca1 compo-it~ aro mat~rlal~ i~

SUBST~ITE SHEFI~ ``

~'094/10351 21~32.~1 PCT/US~3/10360 1~

. - 5 - I :
which one of tha compune~t~ has ~ery high ¦
8 trength, modulu~ or both and the other has high ¦
ductility. Some of th~ir prop~rtie~ generally ~ :~
~ollow th~ rule of mixtur~. Fox ~xampl~, if ~ ' .
ela~tic modulus i5 the property o~ intere~t, the elastic modulu~ of the compo~ite i~
approximately the weighted ~um of the ela~tic moduli of the constituant~.
The term "interm~tallic" i8 used her~in to r~fer to a phase form~d in-~tu a8 a r~ult of chemical and thermody~amic interactio~s. Intermstallic0 may ha~e a rei~forci~g effect. ~owe~er as 3tatad abov~
th~ term ~rein~orciny material" i8 ~ot g~nerally 1.
intended to includ~ intenm~allic~
The term~ "tough~ass" and ~racture toughn~s~ are u~d interchang~ably herei~ to refer to the a~ility of a material to re~i~t -cata~trophic growth o~ a crack. 1:.
The term "laminatQd~ i~ used herei~ to refer to a layered structure ha~in~ at least ~wo -:
layere with di~imilar properti~
The t~rm Rfoll~ i~ used herein to r~fer to ~etal wh~ch has bee~ formed i~to a --~
25 l~yer ~a~ing a thi~kQe~ of 1~ than about 0.15 ;~
mm (0.006 i~che8). Fo~ comm~nly a rollsd ~ ~:
pro~uct haY~ng a recta~gular cro~ sectio~.
. Th~ term "~2~t~ i~ u~d hor~i~ to ref0r to ~etal wh~ch ha~ b~ oE~d i~to a s' .
layer ha~i~g a thick~ gr~ater th~n about 0~15 m~ (0.006 inche~) a~d 1~ tha~ about 6.325 ~m ~ ~-(0.249 ~3ch~). Shee~ ~ 8 com~o~ly a roll~d ~ -product ha~iag a r~cta~ ~ lar cro~ ~sctio~
Tha t~r~ "plate" i~ u~ed h~rai~ to I
35 r0er to m~tal whic~ ha~ b~Q~ formed i~to a ~ay~r ha~ing a ~hic~nss~ great~r tha~ about ~-~
6.32~ m~ (0.249 inchq~. Plat~ i~ com~o~ly a ~U~STt~l~r~ SHEET

W094~10351 PCT/US93/10360 2 æ~ 1 ,.. , ~ ,.

roll~d product ha~ing a xecta~gular cross -section~ ;
By ref~renc~ to Figure 1, thare ~ 8 ~how~ an enlarged ~ros~-s~ction of a~ aluminum 1 :~
5 alloy product produced i~ accordance with the ¦ .
pre~ent i~ention. A ~ection of D~ (lightar color layer) i~ sandw~hed batween two layers of unreinforced alloy, The l~inate alloy product of the inven~io~ ha~ bene~icial propertie~
re~ulting from both typ~s of layar~.
Powder metallurgy may be u~ed to obtaln the alloy~ lam~nated to form the compo~lte structur6 of the pre~e~t inve~ion. ~;
The ~ame alloy may be used in both the unreinforced and rsin$orced layer~ or o~e layer may be comprisQd of a differs~t alloy, depa~ding ~:
to some extent o~ the propertie~ desired in the -~
final product. It ~ preferred that in the reinforcRme~t layers, the r~inforcement material 20 be uniformly di~tr~buted throughout`the product ~:
in order to pro~lde th~ opt~mum combi~ation of strength, toughne~ and ~atiqu~ reai~tance.
I~ maki~g product from aluml~u~ alloy powder, a ba~ alu3~u~ powder alloy such a~ AA
~2080, 6113 or X7093 ~g ~lect~d d~p~ndiny o~
the basi~ propertie2 desirod. For ox~mpl~, powd~r metallurgy alloy X7093 Qxh~bit~ ~igh~r :
10Yol~ o~ strong~h ~d tough~o~ a~
con~tional alloy~ 6uch a~ 7075 an~ 7050.
Furth~r, ~he b~es aluml~um powder alloy c~ be ~ele~ted to produ~ a ~ gra~ tructuro.
Ga~rally, th~ ba~ al ~ nu~ powd~r should ha~ . i a pnrticle ~iz0 i~ th~ r2ng~ of -2QG to -325 mQ~h (Fi~her ~ub-~14v~ ~izi~g ~cr~
~nr~in orc~d alumi~u~ alloy~ h~
capab~li y for good otre~gth ant fractura tough~o~ but heir ~last~c ~odulu i~
~,.

SUBSTITUTE SHEET - ~

WO94/103~1 2 1 1 ~ 2 ~) 1 PCT/US93/20360 t.....

consid~r~d to be le8~ than de~irable for ~ :
st~fne~ critical applications. The addition j of rei~iorc~ment mat~rials, ~uch a~ particle~ of silicon carbide (S~C) to the alloy powd~r, ser~es to enha~ce th~ Qlastic modulu3 with respect to the unrei~forc2d matrix alloy. AY
noted above, the i~corporation of r~in~orc~me~t ~::
particlea d~grades fracture related properties such a~ ductlltty and fracture toughnes~
Surpri~i~gly, the combi~ation o~ layer~ of unrei~orced and rein~orced layers produce a material ha~ing combined improv~mentQ i~ modulu~
o elasticity while mai~tai~ing impro~ed toughn~a 8 . '. .
A~ ~ee~ i~ Figure 1, the rei~forcem~t .~.
mater~al pro~ide~ a m~cha~i~m ~or crack ::
deflsction. Although 30t wi~hing to ba bound by .`-any theory, it is belie~ed that thQ fracture toughne~ o~ th~ lami~ate i8 increased throu~h ~-:
the mechanism~ o~ crack blu~ting a~d crack ~ro~t de lectio~. Crack blu~ting in~ol~e~ impedi~g j::
crack growth. Crack fron~ deflection i~cr~as~
~he area in whlch frac~ure-r~lated eve~t~ occur ~nd ther~for i~cr~a~ the ~nergy ab80rptio~ '`
25 capabllity of th~ ~atorial.~ :
The amount of rei~forcem~t mat~r~al can ra~go ~ro~ a ~ry 8~all amount to a rat~er ~gG~fica~t a~ount if it i8 d~red to gr~tly improve olæ~tic modulus. Typically, th~ .
30 r~in~orc~d lay~r~ or ~egio~ ~r~ ~or~ad ~ro~ a .
~le~d co~prisi~g at l~st 5 ~ol.% of the r~i~forcamo~t co~titue~t with preferred a~ou~t~
bei~g ~t lQast 10 to 30 vol.%. Normally, the bl~d ~hould ~ct comp~ise ~ore tha~ 55 vol.~
The ~aso powder alloy ~d th~ i -re foxc~m~t ar~ ~ix~d to pro~ido a hl2~d wh~rei~ th~ r~ or~mQ~t ~aS~rial i~

SUBSTITUTE SHEET

W94~35~ 43?f'i~ PCT/US93/10360 r _ sub~ta~tiall~ uniformly distributed ~hroughout it. Thereafter, ths blend can be compre~ed to form a compact.
Tha compa~t can be 8ubj ected to a vacuum preheat for purpose~ of degassing.
Typically, for alumlnum, the preheat i~ carried out at a temperaturQ i~ the range of 800 to 1100F. Thereaft2r, it may bs hot pre~sed to provld~ up to 100% den~ity. For aluml~um 10 powder, the compact ean b~ hot pre3sed at a :~
t~mperature i~ the range of 800 to 1100F., a~d pressing ca~ ba carried out at pres~ure~ in the range of 30,000 to 90,000 p5i.
A~ well a~ providi~g the àlloy with controlled amounts of alloying eleme~ts a3 described harein bove, it i8 preferred tha~ th~
alloy b2 pr~pared according to specific method ~teps i~ order to ~ro~ide the mo~t desirab}s characteri~tics. Thus, the alloy described herein can be provided a~ an ingot or billet for fabr~catio~ ~nto a ~uitable wTought product by technique~ curre~tly employad i~ tha ar~. ThQ
i~got or ~illet may b~ preliminarily worked or ~haped to pro~id~ ~ultable stock ~or ~ubs~ue~t worki~ opsrat~o~.
Th~ rei~forced metal ~a3 be rolled or extruded or oth~rwi~ ~u~j~cted to worklng op~ratio~s to produc~ EtoC~ ~uch a~ ~h~t, pla~e .
or extrus~ 0~3 or oth~r ~tock ~uit~le for j shaping ~nto the ~d product. Typically extrudi~g, for ex~mpl~, of th~3 hot pre~ad co~pact, ~hould b~ parfor~ed aS a tsmp~raturo 1 tho r~ge o 550 to 900F. dep~dlng o~ the compo~itio~ o~ tho alloy. .
Th~ r~ orced met~1 she~t or pl~t~
the~ ~tacked ~ alt~rnati~g lay~r~ with unrel~forc~d ~etal. A layer of ~atalli~ :

SU~STllrU~ SHE~

WO 94/103~1 2 14 ~ PCT/US93/10360 ¦."~

.
_ g ~
foil may be placed b~ ween the layer~ to incr~a~e the interlayer adheren~e. The stack i~
the~ roll bo~ded to produce a unreinforc~d laminate having alternatl~g layers or ~trat~ of unsein~or~ed and reinforced material.
ThQ resulting laminate can the~ be formed or worked to the de~ired product, variou thermal op~rat~on~ may be required to obtai~ th~
proper metallurg~cal condition i~ the m~tal. I~ ~-:
th~ case of precipitatio~-hardoned alloys, a solution heat trea~ment i9 used to sub~tantially .
di~solve ~olu~le element~. Th~ ~olution heat treatme~t i~ pre~erably accompli~hed at a -.
temperature in the ra~ge of 800 ~o 1100F. and typically at about 900F. for ~bout 1 hour, Solution h~at treatm~t~ can range .~`~
from ~e~cral minute~ to about 2 hours or more at the ~olution heat treati~g temperature. ~xt~nd- ~:
i~g this ~olution h~sat treatment time beyo~d about 2 hourEi generally doe~i nct pro~ide ~urther im~ro~3ment~i in ~i~al pro~ertieEiO
To ~urther improve the propertieiEi necea~iary to this ~inal product, alloy~ which are ~-.
olutio~ haat treated should bs rapidly qu0~chad ~5 to prs~e~t or ~inimizi~ uncontrolled priscipita-tio~ of variou~ phaseFi whlch, whe~ improperly Eormi3d, i-a~ degr~d~ proport~. A cold w~t~ir ~ue~ch ~ pr~ferred- Thus, it ~i pre~rresd i~
th~ pract~ o~ thii invo~ ion th~ th~ quo~chi~g rate b~ at ~sast 10F./~c wlth a pxe~rr~d que~ch rat~ ~eing at least 100F./sec.
Ths produ~t can b~ arti~ic~ally aged.
Thi~ ~ay b0 a~io~plis~d by ~ub~j~iqtiag thi~ ~5 p~oduct to 3 t~mp~raturiS~ in ~h~ r~g~ o about ,s 200 to 4Q0F. ~or a 8uf~ ci~nt p~iriod o~ t~e to pro~idQ th~ d~ssir~d yield 8~risn~th. Thics peiriod ~or artlSic~al aging can ru~ ~rom si~eral :
', ',`.

5UBSTtTU~ SH~ET

WO 94/10351 PCI`/US93/10360 ~' 2,~ ~82~fc,3 .~ - 10 - 1','''''.!:' ~F~

minute~ to many hour~. For some alloyE~ such a~ , 7XXX serie~ alloya, artl~icial aying i~ t.
accompli~hed by ~ cting th~ product to temperatuxe in the raslge of 250 to 325F, for a peric-d of at lea~t 16 hours.
While re~rence herein ha~ ~a~n m~de to u3ing aluIuinum powder alloy prodncts, it 3bLollid be u~der~tood that me~al other than aluminun~ alloys may be combinad with tho int~nt of increa~ing the . ractur~ resi~tanc~ of th~ ,-final produc~. Such material~ ca~ includ~, for example, metal~ ~uch a~ ~teel ~d titanium or other materials ha~ring properties desirab}e in the f inal produ~ t .
WhilQ the in~rent~ on ha~ :been describad in part with r~sp~3c'c to powder metallurgy, it~
application i8 not nacessarily lim$ted thereto.
That i~, th~ pr~ent invent~ on di~clo~es a metal or alloy structure ha~ring a dual or duplex strucstur~ co~prl~d o~ altsr~a'cirLg strata of ~rei~forced and rai~forc~d m~tal wher~in th~
strata act in combi~atio~ to impro~e the tough~s~, ~tre~th a~d fracture r~ ta~ca o~ :~
th~: structure.
Tho ollowing example~ ar~ o~ered to .
~ llu~tr~1;2 th~ ad~aDt~gss o~ t~ proN~t 1D~Y~t~ on. Th~ X7093 powd~rad alloy usad ~n the ~xampl~0 ~ omm~r~ially avallabl~ from T}~
P~luml~um Co~npany of Am~rica (A.leoa). Tho SlC
3 0 reinforcom~Lt ma~rial uE~d i~ the ~am~
F-600 grade SlC whlc~ i8 c:o~0~ ially a~ai~ Q
~rom Norton Company. 1 . .

A batch o~ powd~r~d alu~i~um alloy, 35 X7093 was cold i~os~atically co~pacted i~to a ~ylindr~c~l ld to 70- B0 % o~ thoor~t~ aal ,:.
de~ity. Thel cyli~dr~-cal Dlc:lel waR ~eal~3d, ;' , SU~3STITUT~ SH'~

WO ~/103~1 PCr/US93/1!1360 ~"
21~32~1 i`

d~gaH~ed and hot pr~ed at 900F. to produce a 100% d~3nsity billat . Th~reafter, th~ b~ llet wa~
extrud~d at 850~. The ~lastic modulus, yield strength tYS~ ar~d ~train at failur~ wer~ t}:,en S measured and r~3corded on Tabl~
Charpy impact t~ts wer~ perormed on notched and un~ntched sample~ of the matQrial o~ :
Example 1 asld th~ r~ult~ ar~ recorded o~ Tables 2 and 3.
Tabl~ 1 Elastic 0.2% O~aet Strai~ At ~xamPle Mat~rial Modulu~* YS . Failure 1 X7093 64.8 573 13 15.wt.~ :
S1~ 98.6 615 4 3 roll bond~d laminate 87.9 582 10 4 roll bonded laminat2 wlth foil 79 . 4 - - .
S adhe~iv~
bonded laminate 75 . 5 575 -2 5 * GPa }~xa~le 2 (Prior Art~
A batch of th~ powd~r~d al~u~n alloy u~2d i~ 13x~ple 1 i8 mix~d wlth 15 ~rol.% ~ co~
carbid~3 part~cle~ to produc~ a u~ifor~ ble~d.
3 0 Tha }: l~nd wa~ the~ proce~ad a~ i~ Exa~ple 1.
T~e elastic ~dulu~, ylsld ~tre:~gth (YS) a~d ~train at failure w~re then mea~ured a~d .
r~corded OSl Table 1. A~ can b~ e~ i:~ Ta~lo 1, ~;.
th~ rei~forc~d material o~ 13xampl~ ~ ~ibl'c~d a t 5296 i~crea~a irL ~nodulu~ csf ~la~ic~t$r over tha ! `~
matarial o 3~x~?le 1 as~d th~ yi~ld ~tre~ h r~ir~ed about the ~e (7% ir~lcrea~
harpy i~act ~e~t~ wer~ perorm~d on ~`~
,','~:

. ' ' SUBST~TUl~ SHE~ ``

, .

W094/10351 PCT/US93/]0360 C~ 8 2 '3 ~

notc~ed a~d unnotched sampleis of the material of Exampla 1 a~d th~ result~ are recorded on Table~
2 acd 3. Ais seen in Table 2, the impact ~ergy (reported a~ total energy) of the notched ' ,:
S sample~ decreased sig~ificantly to approximately 25% of the unr~inorced material of Exampls 1.
Table 3 illustratss that the impact e~ersy ;:
(reported as total energy) of the unnotch~d ~a~ples dropped significa~t}y to approximately 6% of that of the unreinforced material of Example 1. ~ . -The reinforced material of Example 2 had an significant increa~e in mo:dulu~ of ~lastici~y o~er the unreinforced material of Exampl~ 1 but th~ toughnes~ of the material of Example 2 wai3 r~duced. What i~ ~eeded ii9 a ~`
material with the improYed modulus of elai3ticity ~`
that do~i3 not suffer from the dramatic reduct~on in toughne~is. : -Table 2 NOTC D IMPACT T~STING :
Sample Orienta- Maxi3um Total Total Number tlon _ Load ~N) ~nor~Y ~J) Defl~ction 110.23 6.56 1.75 25.41 1.61 0.9 3Arre~or 10.31 17.15 8.20 3Di~ider 6.39 3.88 1.30 .
4Arre~tor 10.74 22.71 10.00 .`
4 DiY~ der 7.27 3.92 1.20 ' f'"

5 Arre~tor 7.48 7.59 5.00 '-S Di~lder ~5.89 2.82 i 0-90 :
* mm : . ;,. .....

' : SUBST~TU~ 5HEEt WO94~10351 PCT/US93/10360 2 ;3 1.

Table 3 UNNOTCH~D TMPACT TESTING I :
Sample Orienta- Maximum Total Total 1.
Number tionLoad (kN~ ~er~Y (J) Deflection 1 100.00 .-~
~ 5.98 .:
3 Arr0~tor46.78 3 Di~ider38.81 4 Arrestor47.46 :~
4 Di~ider34.1~
5 Arr~stor28.48 5 Divi~er15.13 ~ mm ".~
Exa~pl~ 3 Material from Example~ 1 and 2 w~re each rolled to a plat~ thickn~Ha of approximately 0.5 inches and trim~ed. A three layer la~inate ~ormed from two layer~ of tha `~`.
unrein~orced mat~r~al of ~xample 1 ~urrou~ding 20 th~ rein~orced material of ~xampl~ 2 wer~ ,~
producad by fir~t etching the ~urface~ with a solution of ~odium hydroxide and mechaGically .
abradi~g the bo~di~g ~ur~ac~. The layer~ were theu stacked, h~ld together with a ~pot w~ld a~d pre~hoated to approx~:t~ly 850F. The hssted ~-sta~k was the~ pa~s~d 'chrough the nip of roll~r~
and rsduc~d ~pprcxi~t~ly 15% par pa~s f or thr~e pa~ to for~ t~ Lat~
Th~ ela~tic ~nodulua, y~ ~ld s~r~gth ``
~YS) a~d ~tr~i~ a failur~s WQre the~ ~ne~su~ad and ~scorded oa Tabl~ lo A~ ca~ ba ~aer~
Tab1Q 1, th~ la~ated ma~er~al o~ Ex~ple 3 ~ ;
t~d a 3 6 % ~ ~Gr~as el irl ~odulus o ~
~la~ticity ~rer th- m~ter~ al of ~3xampl~ 1 and ' I .
~he~ yle~ld str~ngSh re~ai~ed about tho ~ame ~2%
, -;
increa~e).
~harpy i~pact te~t~ w~re p~rfor~ed o~

. .
............................................................................. ... '.':' Sl3BSTITUTE SltEET ~ `

WO g4/10351 P~r/USg3/]0360 ~, 2 1 ~ t~
- 14 - ,~.
notch~d and unnotched l~minates of th~ material of Example 3 and the ro~ult~ are rf~corded on Table~ 2 and 3. Surprisingly, the impa~t ensrgy (reported a~ total energy) of the notched samplf3s exhibited a~ incr~ace in tough~sa in the crack arr~tor ori~tation ~see F~gur~ 2) of approximately 261% of th~ u~reinforced ~aterial of Exampl~ 1 and an incr~a~e of o~r 1000~ of the reinforced matertal of Exampla 2.
Table 3 illustrate~ that the drop in toughneas or i~pact energy ~report~d as total f nergy~ of the unnotched laminate~ of ~xample 3 was sig~ificantly less than the reinforcad material of ~xample 2. The toughQ~s o~ th~
15 unnotched material of Example 3 was oYer 60~f% -' higher than the reinfor~d material of Exampls 2 i~ both the crack arrestor and crack dt~ider orientations.
Figure 1 illustrate~ the crack blunti~g and interface delami~atioA of the material of Example 3. ~ explained above, i~
i~ belie~ed that the crac~ blunting a~d .
inter~acQ delami~atio~ lead to the matarials :~
hi~h fracture tough~e88. The co~b~nation of high modulus of ela~ticity a~d hi~ toughn~ss (i~ arrestor orientation) of tha lamiaated .
materlal of Ex~mple 3 i2 un~p~ted ~d will be more u~eful i~ aircraft appl~cation~ ~uch as w~gs~ fu~elage and tail aoc~on~ t~a~ e~ther ~.
tha rei~orced or u~reinforce X7093 alQ~s.
Examel~ 4 .
The proc~dure o~ ~xampl2 3 wa~
rep~ated ex~ept that a layer o~ aluml~um ~oil (A
110~ alloy) was placed b~w~e~ th~ u~r~i~ or~ed and reinforced alloy~. Th~ ela~ti~ mod~lus, yield ~trength (YS) a~d ~trai~ at failu~s w~r~
then ~easur~d and recorded o~ Table 1. A~ c~ -SllB~TlTlSIl~ S'rlEE~

WO94/10351 PCT/VS93/10360 -:~
2I(l~
~ 15 - I :
b~ ~en in Table 1, the laminated material of Example 4 exhibited a 22% i~crease in modulu~ of ~la~ticity o~er th~ material of Example 1. 1 :
Charpy impact te~t~ wer~ perfo~med on 5 no~ched and unnotched laminates of the material ~, :
of ~xampla 4 a~d the results are recorded on Tables 2 and 3. Surprisi~gly, the i~pact energy keport0d a8 total energy) o~ the ~otch~d 8ampl28 axhibited an increase in tough~e~ in the crack arrestor orientation of approximately 340% of tha unrei~forced materia} o~ Exa~ple 1 .~
and a~ i~crease of o~er 1400% of th~ rei~forc~d material of ~xample 2. U~expectedly, th~ use of the foil interlayer i~ the laminate of ~xample 4 produced a~ increase in impact e~ergy that wa~
greater tha~ that of the lami~ate formed wi~hout ~oil (Example 3). ;`
Table 3 illu~trates that the drop i~ :.
toughnass or impact e~ergy (reported as total enzrgy) of the u~notched lami~ate of ~xample 4 waa significa~tly le~ tha~ the r~inforced material of Exampl~ 2. Th~ toug~ne~ o~ th~
u~notched mat~rial of Example 4 wa~ over 600~ "
hlgher than the reinforced matQr~al of ~xample 2 '`
in both th~ ~ra~k arr~s~or and crack di~ider orientatio~. The co~bi~atlo~ o~ high ~odulus . .;~
o~ ticity a~d high tou~hn~s~ (i~ arr~or orientation) of th~ la~nated m~t~r~al o~
~xample 4 i~ ~nexp-~ted and will be mor~ u8eful 30 in aircra~t application~ ~uch a~ wing~, ~u~lage '~
and ta~l ~ectio~ than sither th~ rain~orced or unr~ orced X7093 alone, x~pl~ 5 Th~ procedu~e o~ ~x~mpl0 3 wa 35 repaated 8XC~pt th~t th~ laminat~ wa~ adh~s~ely `.
bond~d i~tead of roll bond~d. The adh~siv~
bo~ding wa~ acco~pli~h~d by applying a layer of S~B~IT~TE S~E~

WO94/10351 PCTJUS93/10360 ~ .
~L~ ~2 -~

epoxy to the bonding surface~ after etching.AF1~32~ epox~ which i~ commerically available from 3M corporation i9 ~uitabl~ $or u~e as ~n adhe~i~e. After the adhesive is applied the ~tack i8 formed as i~ Example 3. The ~tack i~
held at approximately 70 psi and 250F. for one hour to cure the epoxy. `~
The elastic modulu~, y~eld strength (YS) a~d strain at failure were than maa~ured.
and recorded on Table 1. A~ can bQ seen i~
Table ~, the lam~ated material of Example 5 :.
exhibited a 16% i~crease in ~odulu~ of ~-ela~ticity o~er the material o~ Example 1. . .
Charpy impact te~ta were performed o~
15 notched and unnotched laminates of the material :~;
of E~ample 4 and the re~ults arQ recorded on ~.:
Table~ 2 and 3. SurpriQingly, the impact e~er~y `
(reported as total e~ergy) o~ the notched :.
samples exhihited an i~creaae i~ tough~e~s in ..
the crack arrestor orie~tatio~ of a~proximately 115% of the unreinforced materia} o~ Exampl2 1 and ac increa~e of over 470~ o~ th~ reinforced material of ~xample 2. ~
Table 3 illu~trate~ that the drop in : :
toughne~ or impact e~rgy (reported a~ total ~nergy) o~ the unnotched laminate of ~xample S
wa~ signific~ntly l~.than the r0i~0rced matfirlal o~ ~xampl~ 2. Th~ toughG~ of th~ j . -u~otc~0d mat~rial o~ ~xa~pl~ 3 wa~ o~er 450%
30 higher tha~ th~ reinforced material of Exampl~ 2 , .
in the crack arr~stor orienta~io~. The , :-combi~atio~ o~ high modulu~ of elaaticity and ,. .. -high tough~a~ rrestor ori~tatio~) of th~
laminated material of Exa~ple S i8 un~xpect~d ~"
aKd will b~ more u0e ul i~ aircra~t ~pplication~
~uch a~ wi~g~, fu~age and tail ~ctio~s tha~
oith~r the rel~orced or unr~i~forc~d X70g3 '~.

SUBSTIJUTF SH~ET

':~

W094~103~1 PCT/US93/10360 .'.
,:,.,,"`` 2 I 4 ~

alo~e.
It is to be appreciated that certai~ ¦
feature~ of the pr~ent invention may be changed without departing from the pre~ent inven~ion. I
5 Thus, or ex~mple, although the invention was ~.
de~cribed.in terms of ~ilicon carbide rein~or~sm~nt material, other rei~orceme~t mat~rials know~ in the art may al80 be us2d. In general, th2se include a wide ~ari~ty of oxid~
carbida2 and nitridea. 5peciically, tita~ium carbide, boso~ carbide, graphit~, carbon, alumi~a, silicon nitride, aluminum nitride, .-~
mullite, titAnium boride, zirconium boride, ~ilicon al~mi~um oxynitride (SiAlON) and 1.
co~binations thereof can also be u~ed as rein~orcement material. ~-~
I~ addition, while the inventio~ ha~
re~erred generally to powdors, it ~hould b~
understood that other method~ may ~ used ~o 20 form the rei~forced m~tal compo~nt of the !.;
lami~ate. Oth~r m~thods i~clud~ ~pray for~ing, pla~ma ~praying, die casting, pressure casti~g, `-rh~oca~ting ~d co~poca~ti~g. `-While the i~QntiQ~ ha~ b~en d~scr?bed ,--terms of forming a thre~ layer l~minate from matexial~ ha~i~g thickne~ of th~ ~am~ order -;
o~ ma~tude, th~ in~ntio~ ia ~ot ~cs~arily . --l~mlt~d th~reto. For example, tha l~ml~ata may b~ ~or~d from a~y ~umber o~ lay~rs. I~
30 expQcted that lami~at~a of f iVQ or ~e~
will bQ ~ou~d to be u~eful in the art. I~ mor~
thaG one r~i~forc~d lay~r i~ u~d to ~orm ths compo~ite it i~ no~ ~ec~s~ary that th0y all ~c-contain thQ ~am~volu~s perce~t o~ ~e~or~m~t 35 material. I~ addition, ~t i~ not ~a~sary that tha layer~ i~ the ~tack al~r~t~ ~tw~n 3 r~infor~d a~d u~r~i~forc~d ~aterlal. For :
SU~3STITUTE 5HEET

3 t;?,~ 5 ~ ~

example, the lzminate may be formed from five of layer~ with the fir~t and fifth layers being f~bricated rom unrei~forced material and th~
necond and ~orth layers fabricated from a l, :
S material containing 8 ~ol.~ rein~orcement and ! ~:
the middle or third layer containing 18 vol.%
rein~orcement. Furthermore, it i~ contemplated .;
that some of the layers ~ay have a thick~eQs which i8 substantlally thinner than other~ and lO yet ~till thicker than oil. .
In addition, while the inventio~ has referred generally to for~ing laminates from separate and distinct layer~s of compo~itionally homogeneous ~lat rolled product, it should be ~.
15 underi3tood that khe laminate of the pre8ent ` .
invention i8 not 80 l~mit~d. Each layer of material to be used in the laminate may be - ~;
formed from ~pray fo ~i~g or plaii3ma isprayi~g technique in which the amount o~ the reinforcement i~ varied as the metal produc~ i8 being depoisited. Thus, the ~olume percent o~
reinforc~ment material may be vari~d acrois~ the thick~e~s o~ the rein~osc~ment layer. Thiis -~ariatio~ i~ ~olume percent may b~ abrupt or gradual depe~di~g on ~h~ desir~d outcome. In additio~, it i3 contemplated that the e~tire laminate may be formRd by changi~g the altsrnati~g the ~olum~ parc~t of particulate ~. :
material fro~ be~ow 5 ~ol.~ to abo~o 5 vol.% aQd th~r~by form the dual structurQ ~u~reinforced and reinorced lay~r~) w~h a ~i~gle 8p~yl~g.
~imilarly, th~ composition o~ tha alloy that i0 bei~g depo~ited may b~ ~aried withi~ ~ach lay~r 1` `
or ~h~ ~n~ir~ structur~. I~ additlo~, it i~
co~te~plat~d that e~ch layer ~eed not ext~nd the 0ntir~ le~gth or width o~ th~ product.
While th~ ntio~ ha~ bQe~ de~cribed :~

SUBSTITUTE SHE~ET

W094/~0351 PCT/US93/20360 2 1 ~

- 19 - ~ .
term~ o~ roll bondi~g ~nd adhe~ive bonding, it will be understood that th~ ba~ic invention i~
not nece~arily limited thereto. For example, ¦-layer3 may be laminated by explo~ive bonding, 5 difu~ion bonding, extruding a~d other bonding i.~ -techniques known in the art.
Furthermore, while the i~ention ha~
b~en described i~ part with respect to alumi~um and it~ alloys, it will be under~tood that the invention i~ not nece~sarily limited thereto.
For example, the dual structure effect ha~
applicatio~ to other metal structures auch a~ .}
steel, titanium and other alloy~, and such i~
contemplated within the purview of the 15 invention.
Wherea~ the preferrad embodiments of the pre~ent invention have been described above in term~ of being e~pecially valuable in producing X7093 aluminum alloy parta, it will be 20 apparent to those skilled in the art that the present invention will al~o be valuable producing laminated composite~ made of other aluminum alloy~ containing abol~t 80 percent or mor~ by waight of aluminum and o~e ox more 25 alloying elemQnts. Among ~uch suitabl~ alloyi~g elements i~ at lea~t one element Relect~d ~rom .
the group o ~entially character fo~ni~g alloyiBg ~l~ms~t~ and consi~ti~g o~ ~a~ga~e~e, zin~, b~ryll~um, lithi~m, coppQr, ~ilico~ a~d ~i :
30 mag~esium. I ter~ thes0 alloyi~g alamo~t~ a~ , e~s~tially character forning for ~he r~a~o~ t that the co~t~mplat~d alloys co3tai~i~g o~e or mor~ of th~m ffD~ntlally deri~ thelr ; :
charactQristic propQrtie~ ~rom such ela~t~. t' 35 ~ually th~ amounts o~ ~ac~ o~ the elQ~e~ts ,.
which impart such characteri~tic~ are, as to '`
Qach of ~agnes~um a~d copper, a~out 0.5 to about SvBsTlTuT~ St~E~T

WO94tlO351 PCTlUS93/l0360 ~ - 20 -10 wt.% of the total alloy if the element i~ ~ .
present a~ an alloying element in the alloy; as ~ -to the el~m~nt zinc, about 0.05 to about 12.0%
of the total alloy if ~uch element i~ pre~ent a~ I -5 an alloying element; a~ to the el~me~t ` :`
beryllium, about 0.001 to about 5.0~ of the .:
total alloy if such element is pre~ent a~ an alloying element; as to the element lithium, about 0.2 to about 3 . 0% of the total alloy if 10 such eleme~t iB pre~ent as an alloying el~me~t; --and as to the element ~a~ganese, if it i~
pr~ent as an alloying element, usua11y about 0.15 to about 2.0~ of the total alloy. .
The element~ iron and ~ilicon, while perhaps not entirely or always accurately cias~ifiable a~ essentially character forming alloy element~, are often present in alumin~m ~:.
alloy in appreciable quantities and can ha~e a marked ef fect upon the derived characteri~tic --20 propertie~ of certain alloys containi~g the ~.
same. Iro~, for example, which i~ often present and co~sidered a~ an u~desir~d impurity, i8 , ~`
oftentimes de~irably pre~ent and adjuRted in .~.
amount~ o ~ out 0.3 to ~OO wt.% of th~ to~al 25 alloy to p~rform ~peci~ic functio~s. Silico~
may al~o bo 80 consider~d, and wh~l~ fou~d i~ a . ~:
ra~g~ varying fro~ about 0.25 ~o a~ ~uch as 15 ~ mor~ often de~irably fou~d i~ the rang~ of -about 0.3 to 1.5% to p~rfor~ Yp~ciflc fu~ckion~
30 In light of the foregoi~g dual nature of these ~ nt~ a~d for conYe~ienc~ of definition, th~
el~nt~ iron and 8il~ C0~ m~y, at l~axt whe~ , ~:
de3irably pr~e~ in character af~ecting amounts r i~ certain alloy~, b~ propQrly al~o co~sid~r~d 35 a~ charact~r fo~mi~g alloying i~grsdi~t~
Such alumi~um a~d alumi~u~ alloy~, whlch may contai~ one or mor~ of th~e e~e~tial TJTUT~ ~H~ET

, :

WO94~10351 P~T/US93/10360 2 1 ~ ,~ 2 ~
- 2~ -character ~orming el~ments, may contain, either ¦ ~
with or without the aforementio~ed character ~ ~:
forming el~me~ts, qua~titie~ of certain wall known ancillary alloying ~l~ments for the 5 purpose of enhancing particular propertie~.
Su~h ancillary Ql~ments are usually chromium, nick~l, zirconium, vanadium, titanium, boron, lead, cadmium, bismuth, and occasio~ally ~ilicon .
and iron. Al~o, while lithium ia li~t~d a~o~ ~
10 an e~sential character ~orming element, it ~ay ;`
in ~ome i~sta~ce~ occur in an alloy a~ a~ ~.
ancillary ~lement i~ an amount with~n the range outlined above. When one of the~e ancillary el~men~s i~ present i~ the alumi~um alloy of the .-15 type her~in contem~lated, the zmou~t, in term~ -~
o~ percent by weight o~ the total al}oy, ~aries .:
with the element i~ que~tion but i8 u~ually . -.
about 0.05 to 0.4%, titanium about 0,01 to 0.25%, vanadium or zirco~ium about O.OS to 0.~5%, boro~ about 0.0002 to 0~04%, cad~um about 0.05 to 0.5%, and bismuth or lead about 0.4 to 0.7%. :
Ths aluminum al}oy3 i~cluded mo~t :~
px~f~rably the wrought and forged alumi~um ~.
alloy~ ~u~h a~ tho~e registared with tha Aluminum A830ciatio~ by the de81gnations 2014, 2017, ~117, a6~8, 221g, 241~, 2024, 2124, 2224, .
2036, 6101, 6201, 6009, 6010, 6151, 6351, ~951, 6053, 6061, 626~, 6063, 6066, 6070, 7001, 7005, ~: ;
?016, 7021, 7029, 7049, 7~0, X7093, ~150, 7075, 7175(b), 7475, 7076, 717~ a~d other appropria~
alloys o ~imilar d~sig~ation. O~ particular i~t~r~t ar~ tha aluminum alloy3 ~2080, 6113, ,::~
X7093. The~ alum~u~ alloy~ g~erally i~clude i ~-th~ ge~ric d~ atio~ 2000 aer~ lloys, 6000 :~:
~Qrie~ alloy~ and 7000 ~ri~ alloys. The ca~t ~ ;
alloy~ treatabl~ by ~he pr~n~ ~n~e~t~o~ ' SUBSTITUTE SHEET .-, W094tl0351 P~TJUS93/103fiO l. . `
2i'1~

- 22 ~
include mo~t preferably the ca7t aluminum alloy~, ~uch a~ those de~ignated 222, 242, 295, 296, 319, 336, 355, 356, and 712. These ca~t al~oys generally have the generic de~ignation j :~
200 ~erie~ alloys, 600 ~eries alloy~ and 700 ~erie~ alloys.
Theae and other chang2~ of the type de~cribed could be made to the prese~t invention without departing from the ~pirit o~ the ~ .
inventlon. The scope of the pre~ent invention i~ indicated by the broad genera} ~eaning of the t~rm~ in which the claim~ are expre~sed.

:

,",,.", ~

, .

SU6STITUTE SHEET 1~

Claims (34)

C L A I M S

1. A laminated metal matrix composite comprising a laminated stack of alternate layers of unreinforced metal and reinforced metal.

2. The metal matrix composite of claim 1, in which the thickness of said unreinforced layers are of the same order of magnitude as said reinforced layers.

3. The metal matrix composite of claim 1, in which said unreinforced layers and said reinforced layers have a thickness greater than about 0.5 mm.

4. The metal matrix composite of claim 1, in which said unreinforced metal is an alloy of a metal selected from the group consisting of aluminum, copper, iron, titanium, magnesium and zinc.

5. The metal matrix composite of claim 1, in which said unreinforced metal is an aluminum alloy.

6. The metal matrix composite of claim 1, in which said reinforced metal is an alloy of a aluminum, copper, iron, titanium, magnesium and zinc.

7. The metal matrix composite of claim 1, in which said reinforced metal is an aluminum alloy containing at least 5 vol.% of reinforcing material.

8. The metal matrix composite of claim 1, in which said reinforced metal contain particles selected from the group consisting of boron carbide, silicon carbide, silicon nitride, graphite, alumina, titanium carbide, carbon, silicon nitride, aluminum nitride, mullite, titanium boride, zirconium boride, silicon aluminum oxynitride (SiAlON) and combinations thereof.

9. The metal matrix composite of claim 1, in which said reinforced metal contain particles of silicon carbide.

10. The metal matrix composite of claim 1, in which said reinforced metal contain particles of silicon carbide having an average particle size of less than about 50 microns.

11. The metal matrix composite of claim 1, in which said unreinforced metal and said reinforced metal are formed from different alloys.

12. The metal matrix composite of claim 1, in which said unreinforced metal and said reinforced metal are formed from different aluminum alloys.

13. The metal matrix composite of claim 1, in which metal foil in interlayered between said unreinforced metal and said reinforced metal.

14. An aircraft tail section or empennage which is at least partly formed from the laminated metal matrix composite of claim 1.

15. An aircraft wing which is at least partly formed from the laminated metal matrix composite of claim 1.

16. An aircraft wing comprising a plurality of laminated panels of layers of unreinforced and reinforced aluminaum alloy.

17. An aircraft tail section comprising a plurality of laminated panels of layers of unreinforced aluminum alloy and the same aluminum alloy having 5 to 55 vol.% of particulate material of silicon carbide.

18. An aircraft wing or section thereof comprising a plurality of laminated panels of layers of unreinforced aluminum alloy and the same aluminum alloy having 5 to 55 vol. % of particulate material of silicon carbide.

19. A method for producing a metal matrix composite having increased combination of elastic modulus and fracture toughness, said method comprising the steps of:
(a) providing a plurality of layers of unreinforced metal and reinforced metal;
(b) stacking said layers; and (c) applying sufficient heat pressure to said stack to cause interlayer adhesion of said layers.

20. The method of claim 19, in which step (a) further includes:
said stack of layers comprises alternate layers of unreinforced metal and reinforced metal.

21. The method of claim 19, in which step (a) further includes:
said stack of layers comprises alternate layers of unreinforced aluminum alloy and reinforced aluminum alloy.

22. The method of claim 19, in which step (a) further includes:
said stack of layers comprises alternate layers of unreinforced metal and metal which has been reinforced with particles selected from the group consisting of boron carbide, silicon carbide, silicon nitride, graphite, alumina, titanium carbide, carbon, silicon nitride, aluminum nitride, mullite, titanium boride, zirconium boride, silicon aluminum oxynitride (SiAlON) and combinations thereof.

23. The method of claim 19, in which comprises:
roll bonding said stack of layer to form a consolidated product.

24. The method of claim 19, in which step (b) further includes:
adhesively bonding said stack of layers to form a consolidated product.

25. A method of producing an aluminum alloy having a combination of improved fracture toughness and elastic modulus, said method comprising the steps of:
(a) providing a first aluminum powder alloy;
(b) admixing with said first aluminum powder ally a reinforcement material to provide a blend;
(c) pressing the blend to make a green compact;
(d) hot pressing said green compact;
(e) working the hot pressed compact to produce a first product flat rolled product;
(f) providing a second flat rolled aluminum alloy product;
(g) stacking said first and second products to form at least three alternating layers; and (h) laminating said stack.

26. The method of claim 25, in which further includes:
heat treating said stack.

27. The method of claim 25, in which said first and second flat rolled products are formed from the same aluminum alloy.

28. The method in accordance with claim 25, wherein said reinforcing material is at least 5 vol.% of the blend.

29. The method in accordance with claim 25, further including the step of vacuum preheating the green compact for purposes of degassing.

30. The method in accordance with claim 25, further including the step of heat treating said stack at a temperature in the range of 800°
to 1100°F.

31. The method in accordance with claim 30, including the step of aging the product after the heat treating step.

32. The method in accordance with claim 25, including the step of artificial aging said stack at a temperature of 200° to 400°F.

33. The method in accordance with claim 25, in which step (h) includes roll bonding said stack to form a consolidated product.

34. The method in accordance with claim 25, in which step (h) includes adhesively bonding said stack to form a consolidated product.