CHARACTERIZATION OF Al2O3/TA6V AND ZrO2/TA6V CERAMIC-METAL INTERFACES

(1)

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CHARACTERIZATION OF Al2O3/TA6V AND ZrO2/TA6V CERAMIC-METAL INTERFACES

C. Peytour, Franck Barbier, P. Berthet, A. Revcolevschi

To cite this version:

C. Peytour, Franck Barbier, P. Berthet, A. Revcolevschi. CHARACTERIZATION OF Al2O3/TA6V

AND ZrO2/TA6V CERAMIC-METAL INTERFACES. Journal de Physique Colloques, 1990, 51 (C1),

pp.C1-897-C1-902. �10.1051/jphyscol:19901141�. �jpa-00230053�

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COLLOQUE DE PHYSIQUE

Colloque Cl, suppl&ment au n O l , Tome 51, janvier 1990

CHARACTERIZATION OF A120,/TA6V AND Zr02/TA6V CERAMIC-METAL INTERFACES

C. PEYTOUR, F. BARBIER, P. BERTHET and A. REVCOLEVSCHI

Laboratoire d e Chimie des Solides, UA CNRS 446, Universite Paris Sud,

B&.

414, F-91405 Orsay Cedex, France

Resume - Des l l a l s o n s p a r b r a s a g e a c t . l f o n t e t e r e a l l s e e s e n t i e l ' a l l l a g e de t i t a n e 7 1 - - 6 A l - 4 V (TA6V) e t l e s c e 7 - a n i i q u e c ~ R1:O-r. et, L - l i z . L ' a l l i a g e de b r a s u r e u t i l i s e a i a cotnpoc;l t i o n C:u. clOAq- 5T I . Des ;-ear: t.l'.,i~s.

c h i m l q u e s complexes se p r o d u l s e n t dans l a zone i n t e r f a , : l a l e e t . c o n d u i s e n t a l a formation de phases de d l f f e r e n t e s somposlt,lons. Le compose Cu2 ( T 1 ,A1 ) 4 0 e s t obse,-ve a l ' i n t e r f a c e bi-.7sure/cer-amlqi~e. A p r o x l m l t e du m e t a l de b a s e , des phases I n t e r m e t a l l l q u e s Cu - T I s d r ~ t o b s e r v e e s . Le% m i c r o s t r u c t u r e s des l n t e r - f aces TA6ViAl,.O: e t l i ; k ~ \ : ; ' Z r l ? / s o n t t r e s s e m b l a b l e s a l o r s que l e s p r o p r l s t e c , n ~ @ s a n l q u e s F # ! - ~ s e r ~ t e n t der.

differences n o t a b l e s : l a r e s l s t a r l c e

a 1a

t r - i i c t l o r i ! i i 6 3 u r ~ e pc.ol- I P J C L i i t TA6V/A1,-O3 ( 3 M P a ) e s t t i - e s i n f e r - l e u r e a e l l s du :lolr-~t. TAGi'/Zr'O,.

( 1 5 0 MPa).

A b s t r a c t - A l u m i n a and 21;-conla were j c l n e d t o a T i r j A l .l6: .ill':\.y. ( l i - : : ; ? / ! clsir19 an a c t . l v e b r a z e o f cornposi t i o r . C U - . ~ O A ~ . - ~ T I . The l r i t a r f ace I - e q i o r ~ 1 % 5 h W n t o be v e r y coiriplc-X, C t . l l s l S t ~ i i ~ ~ G? n u m e t - o u ~ la.;ei-F. .>f v.3r ,.lnf.i composition and t h i c k n e s s . The c h e m l s a l l n t e r a i t , l o n o f t h e b r s z e w 1 ~ h

t h e ceram1.c r e s u l t s I n a C u ; ( T l , A l ) s r _ ? l a y e r - . I>J.ja(:ertt. t o t h e 11:f~::l .l',;

base m e t a l , a s e r l e s o f <:U-'r1 i n t e i - m e t a l i l c phases 1 s c.tz.erveG. 7 l,?

TAGV/AlrOr and TAf2L1/ZrO; l r i t e r f a c e r e q l o n s e;<hll>~'; r a t h e , . r ; l m l l a r m l c r o s t - , I - u c t u r e s . I-lowever , t.he merhar:lc;al p r o p e m F t i . e s of t h e : ~ d ~ . r i t r. I n

t t i e s e two systems a r e v e r y d i f f e r e n t . The t e n s l l e s t i - e n q t h o f (.tic j o l n t , 1s s l 9 n i f i s a n t i y l o w e r l r i t h e c a s e o f TA:,V/A12rj:, ( 3 r I P a ) t.tlari f ~ r T A G V i 2 r 0 2 ( 1 50MPS? ) .

1 INTRODUCTION

I n many c u r r e n t 1 n d u s t . t - l a l a p p l i c a t l - o n % , c e r a m i c s must 'ss ] . ? I rie1-l L(.> . S niet.i i ^{L ? ! -} t o a m e t a l l l c a l l o y . .Exalnples include e n g i n e components. e l c s t r c)rii c de\.,icer'.

and c e r a r n l c / m e t a l composl t e s

.

The p i - o c e s s e . ~ d e v e l nped t,? f nrm s l.i-;?n,? arid r e l i a b l e j u l n t s have t o overcome t h e l a r g e l y d l f t e r l ! i n , p,-oper t , ~ e c , o i cc!-cir11 I..-.

and m e t a l s / l / . There a r e t h r ee ma ]r>r t y p e s o f ]cl n l n m ) t ~ : : t ~ r - t l ~ ~ ~ ~ ~ ? ~ : ( 1 ) r n e c h a r ~ r c a l jo l n l n y , ( 2 ) d r r e c t j o l n l n s . s r ( 3 ) l : i < l r - e c t ~ o l n l n . 4 ;?,

Brazing 1s one o f t h e rominonl\/ eini>lo,/ed r n d l r e c t t,echniques f z i - w t - ~ 3 . ; t i ri,.?!.sl b r a z e a l l o y s l r ~ c l u i l l n g a c t l v e e l e m e n t s ! C . ? . , T 1 ) we: e .-JevFilo~'ed I n <,;'7i+i- i .,,

m o d l f y t h a c h e m i s t r y e f t h e c e r - r m i c s u r f ace and tierice

,

t o 1 inlr..,- c?vo t..tif:: r!r.?.t.l r?r.j o f t h e c e r a r l l c b y t h e l l q u l d b r a z e / 2 , 3 / . The i r i t erac.t,~.Qri b c t l . ~ e e n th e ri1et.a l and t h e ceramic d e t e r - m l n e s t h e s t r l . l c t u t - e o f t h e ~ n t u r f a c f and tizn:.e t.:?s p r o p e r t i e s c f t h e s y s t e n i . I t 1 s t h e r e i o r e lmpor t,ant t o under-.t:rr,d arid cor;t.r \ , l t h e c h e m l c a l r e a c t i o n s whl(:h occur- a t t h e cersmic:rnetal l n t e r - F s c z . I?:>I-ECL.E~-, t h e m e c h a n i c a l p r - o p e r t l e s o f t h e :l:loint have t o b e IKnowrt f o t - a c,c,mp.rete

c h a r a c t e t - l z a t , l o n o f t.he ~ n t e r f a c e . . T h e wcJrk prescsntoci tjei-e ;oi!Zlc;?.c; ^{~ r . 1} I h e i d e n t l f l c a t i o n 9 f t h e mlcrostru.:tui-e ancl c.c~mposltlisn o i l r ~ t . e ~ ~ ~ s i . l ~ l ~~iirir;'.x!ri.'l:.

f o r m e d upon b r a z l n q o f t i t a r i l u m a l l ? y TALV and a l u m l n d .;r r l i $:i;nla. T t : r mechanical behaviour o f t h e JOI n t s 1 s a l s ~ s t u d l e j a n 21 5cuc-.sec'.

0 - EXPERIMENTAL ( a ) M a t e r l a i r

The c a r a m l c s w h i s n were used ar-e made b./ Ce;aml!que.s Tect~t?l,q!~es I-i;inc~e. 11.1s a i u m l n a i s 9 7 . 8 $6 AizO:~ ( a v e r a a e g r a l n s l z e ? 4 kiln) and t h e z l l c . u r i l d 15.

p a r t i a l l y c t a b l l l z e d wlt,h 3 m c l . % 'YzO-, ( a v e r a g e g r a i n s l 2 1 ? c: 0 . 3 5 l : ~ n ) TPIF c e r a m i c s were j o i n e d b y a r t . l v e b r a z l n q t,o a TI Gal 4 V wt '; s l l o . , ~ Cler.lc,rut,e.i .ic.

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Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19901141

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Cl-898 COLLoQUE DE

PHYSIQUE

~ n t e r g r a n u l a r phase (78.5T1-3.7A1-17.8V a t % ) . The b r a z l n g f l l l e r m e t a l 1 s g l a s s y r l b b o n o f Cu-4OAg-5T1 w t $6 ( a b o u t 80 ym t h l c k ) and 1 s p r o d u c e d b q Vacuumschmelze GmbH-Germa~y. Thermal e x p a n s l o n c u r v e s o f t h e materials use t h l s s t u d y a r e p r e s e n t e d ~ n F l g . 1 , on w h l c h one c a n see a r a t h e r s l m l l a r be'havlour o f Zr02 and TA6V.

Samples were p r e p a r e d ~ n disc f o r m , 10 mm l n d l a m e t e r and 5 mm thlck8. The c e r a m l c s u r f a c e s were p o l l - s h e d t o a m l r r o r f l n l s h ( 2 ym dlamond) t o l n c r e ~ w e t t l n g ; t h e r n e t a l l x c s u r f a c e s had a 8 p m dlamond p o l l s h . B r a z l n g was p e r f o r m e d b y h e a t l n g samples f o r 2 t o 10 m r n u t e s ~ n a vacdum f u r n a c e

( X 3.10-5 T o r r ) I n t h e t e m p e r a t u r e r a n g e 8 5 0 - 8 9 0 ° C . and s u b s e q u e n t l y c o o l ) them t o room t e m p e r a t u r e I n 4 h o u r s .

( b ) f l l c r o s t r u c t u r a l c h a r a c t e r l z a t l o n o f b r a z e d j o l n t s

C r o s s s e c t l o n s o f t h e TA6V/A1203 and TA6V/ZrO2 interfaces were c h a r a c t e r 1 2 b y s c a n n l n g e l e c t r o n r n l c r o s c o p y (SEM) and e l e c t r o n p r o b e m l c r o a n a l y s l s . I r a d d l t l o n , t r a n s m l s s l o n e l e c t r o n m l c r o s c o p y (TEM) and e l e c t r o n d l f f r a c t l o n were used t o Image t h e phases a t h l g h e r resolution a n d t o g l v e c r y s t a l s t r u c t u r e ~ n f o r m a t i o n .

( c )

Mechanical

s t r e n g t h measur-ements o f b r a z e d j o l n t s

The mechanical s t r e n g t h o f t h e j o l n t s was e v a l u a t e d b y t e n s l l e t e s t s c o n d ~ a t room t e m p e r a t u r e o n b r a z e d samples h a v l n g t h e c o n f l q u r a t l o n represent,er F l g . 2. The f r a c t u r e s u r f a c e s were examlned b y SEM.

1O'.A111

TAGV

t

TAGV

J

F l g . 1 - Thermal expansion c u r v e s o f F l g . 2 - M l c r o g , - a p h s h o w l n q t h e t e r

TH6V, A1203 a n d Zr-02. specimen.

3

-

RESULTS

( a ) M l c r o s t r u c t u r e .of b r a z e d j o l n t s

F l g u r e 3 illustrates t h e microstructure o f a TA6V/A1-0; b r a z e m e n t . The e l e c t r o n m l c r o p r o b e c o m p o s l t l o n a l l l n e s c a n o f t h l s ~ n t e i - f a c e { F l y . 3 c )

~ n d l c a t e d t h a t complex c h e m l c a l reactions o c c u r r e d between b r a z e a l u m l n a t h e t l t a n l u m a l l o y . I n particular, segregation o f T 1 t o t h e b r a z e / L \ l n O ~ interface was r e a d l l y seen.

A d j a c e n t t o A l 2 0 3 , a continuous ancl s l n u o O s l a v e r ' ' a " ( 2 2 - 3 um t h l c k ) whc c o m p o s l t l o n 1 s 50Ti-35Cu-15A1 ( a t % ) was o b s e r v e d . TEN observation showec t h a t l a y e r " a " i s made o f e q u l a x e d g r a l n s t h a t a r e l a r g e r f a r t h e r f r o m $1, ( F l g . 4 a ) . Very few d l s l o c a t l o n s were o b s e r g e d 1r1 t.he d l f t e r e n t g r a l n s wh:

were ~ n v e s t l g a t e d . E l e c t r o n d l f f r a c t l o n l n d l c a t e d t h a t p h ' 3 5 e " a " has a ctii:

s t r u c t u r e w l t h a l a t t l c e p a r a m e t e r a

=

11.13

+

^0.10^# ( T a b l e 1 : rig. 4 b ) . c r y s t a l l o g r a p h l c f e a t u r e s o f t h l s phase a r e s l m l l a r t o t h o s e r - e p o r t e d f c r t e r n a r y o x l d e Cu2T140 / 4 , S / . M o r e o v e r , t h e ( T l + Q l ) i C u e w e r l m e n t a l r a t l o b

f o u n d e q u a l t o 1.9 w h r c h i s l n r a t h e r good agreement w l t.h t-hc? Tl;Cu s t , i n t h e compound C u ~ T 1 4 0 . T h e r e f o r e . a l t h o u g h e l e c t r o n m l c r c p r o b f a r i a l j , s l s o f

. , .,

oxygen 1 s m l s s l n g , our- d a t a l e a d t G t h e conclu?li;r~ t h a t l a ? , o , - 1s t h e ⁽

r r r m n n l ~ n A r l l - l ' r > A 1 l . n w i t h 7 3 < T l / A l ^,' 5 . 6 .

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F l g . 3

-

C r o s s - s e c t l o n o f t h e TA6V/Cu-Ag-Tl/A1203 interface a f t e r b r a z l n g : ( a ) SEM r n l c r o g r a p h . ( b ) Schematic d r a w l n g , ( c ) M l c r o p r o b e l l n e s c a n s s h o w i n g t h e c o r n p o s l t l o n v a r l a t l o n a c r o z s t h e ~ n t e r f a c e .

F l g . 4

-

( a ) TEM m l c r o g r a p h s h o w l n g t h e r n l c r o s t r u c t u r e o f t h e Cu2(T1,41)40 l a y e r a d ~ a c e n t t o A1203. ( b ) E l e c t r o n d l f f r a c t l o n of C ~ ~ ( T 1 , 6 1 ) ~ 0 ; t h e zone a x i s 1 s [ O l O ] .

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Cl-900 COLLOQUE

DE PHYSIQUE

:t?r

.

?::<.:..I - 1 , ..r t ;.,c. ^.;.-F; ^b~~ L t ? t.l;r :5.rl,se r~vet,.ll ,ia;,e a ^sei-let,o f l n t e r f a c i a l

D ~ I ~ S E S . i\.3 i...4i'r~t. t,:, ' l i \ ~ ' > . S laine'L1ai- s t r U c t U r e ( " f " ) was t ormed. I t consic- o f .ir: o 1 1 phase ( b l a c k chac,e 1r1 l- l g . 3 3 ) and a phase " E " whose ccirnpositlc (;?.KT 1 2.1.~.i:u 5.t,A1 a t ? g . L l e c t r a n . 3 i f f r a c t l o n showed t h a t " E " has an i - ~ r x ~ , ? o n a l s t i . ~ i t , u i ' e ( T a b l e 1 ) . A r e v l s w o f t h e l l t e r a t u l - e r e l a t l v e t o c r y 2

c c - ,

,,,

u c t ~ i - e c . , ) f .; r ~ t . e ~ - n 1 e t . 1 1 p h s s o s / G / l n d l c a t e d t h a t t h i s phase has

c . r ~ s t a l l o q r . , r l p h i c c l - t a r a c t e r l s t , ~ c c s s l m l l a r t o t h o s e o f T l j S n and P415Sn. l a k i 1nt.o a?r:ot.!r,t that. t.he ( 7 1 t A \ l ) / C u e x p e r i m e n t a l r a t i o 1 s approximately 5 : 1 , we c a n p i a p o s e t h e formulation ( T 1 . A ~ ) J C U f o r phase " E " . F a r t h e r , we f l n d phases " e " . " d " a n j " c " w h i c h a r e e s s e n t i a l 1 y made o f Cu and T 1 ( F i g . 3 c ) . Phases " e " and " d " have b c t h a t e t r a g o n a l s t r u c t u r e ( T a b l e 1 ) w h i c h 1 s c o n s ~ s t e n t 1respectlveJ y w l t h t.hat o f t h e T i l C u and 71Cu compounds. Concer now l a y e r " c ' ' , i t cart b e deduced f r o m f l g . 3 c t h a t t h l s l a y e r i s t h e compc T L ~ C U Z , ( T a b l e 1 ) . However. l n some a r e a s o f t h e " c " l a y e r , g r a l n s c o n t a i n 1 up t o 12 a t % A1 were a l s c i d e n t l t i e d . These g r a l n s , w h l c h have a n

0 8 - t . h o r l ~ ~ o m b ~ i . s t r u c t u r e ( T a b l e 1 ) . can be l d e n t l f l e d w i t h t h e T i ( C u , U l ) 4 compound. L a s t , some discrete particles " b " w h l c h a r e an A g - r i c h s o l u t i c a r e embedded l n l a y e r " c " .

T a b l e 1

C h a r a c t e r l s t l c s o f t h e phases f o r m e d l n t h e TA6V/Cu-Ag-Tl/AJ203 j o i n t

The m i c r o s t , r u c t u r e o f t h e T U 6 V / Z r O ~ b r a z e m e n t s exhibited l n t e r f a c l a l c h a r a c t . e r l s t , l c s which a r e vet-.{ s l m l l a r t o t h o s e o b s e r v e d I n t h e s y s t e m T A ~ V / A L ~ O I , t h e same i n t e r f a c l a l r e a c t l o r t p r o d u c t s b e l n g f o r m e d I n t h e twc s y s t e m s . However, some f e a t u r e s a r e d l f f e r e n t :

-

Iz

1 s w o r t h r i o t l n q t h a t t h e z l r c o n l a c l o s e t o l a y e r " a " 1 s b l a c k e n e d a b r a z l n q , w h l s h l n d l c a t e s oxygen deficiency f o r t h e c e r a m l c . Thus, t h e ? a s o u r c e o f oxygen a t t h e b r a z e / c e r a m l c I n t e r f a c e because o f t h e o x y g f r n o 0 l . l l t y l n ZrO?. R e v e r s e l y , no d l f f u s l o n o f z l r c c n l u m I n t h e b r a z e w a obser-vezl.

-

I n b o t h s v s t e m s , alumlnum 1s d e t e c t e d ~ n i n t e r f a c l a l l a y e r s c l o s e t o t r-ei-amic. l-lowever, t h e A1 concentration 1 s l o y e r l n t h e c a s e o f TH6V/Zr

tt,an f o r TABV/A1203. T h l s t r e n d indicates some d i f f u s i o n o f U1 f r o m A I 103 l n t o t,he b r z z e .

1-ay e r s

3 0 C

1 :

C,

( b ) Tensile s t r e n g t h o f b r a z e d j o l n t s

A s can b e seen I n T a b l e 2, t h e mechanical behaviour o f t h e two t y p e s o f samples 1 s vet-;., d i f f e r e n t . The f r a c t u r e s u r f a c e s o f t i ? e samples a r e a l s o f different (Fig. 5 ) . T h l s can be d i r e c t i v r e l a t e d t o t h e difference between t h e r m a l expansion c o e f f l c l e n t s o f A1;Oz. ZrO; and TH6V ( F l g . 1 ) .

C r y s t a l s t r u c t u r e s

c u b l c c u b i c t e t r a g o n a l o r t h o r h o m b i c t e t r a g o n a l t a t r a g o n a l h s x a q o n a l h e x a q o n a l

I t can b e seen t h a t l n t h e c a s e o f A l x O j , f r a c t u r e has t a k e n p l a c e w l t h i n c e i ' a m ~ c and 1s m o s t l v l n t e r g r a n u l a r ( F l g . 5 a ) . Ruptui-e r e s u l t s o f p r o p a g a t o f .>rzzk:. a l r e a d b , f o r m e d I n t h e c e r a m l c n e a r t h e i n t e r f a c e upon c o o l i n g f r t,t-re b r d z l n q t e m p e r a t u r e . Tn t h e c a s e o f 21-02. a l l samples f r a c t u r e d w i t h l r 1c)lnt. a r e a n e a r t h e Zi-07 z u r f a c e and I n no c a s e r u p t u r e had p r o p a g a t e d 1r-1.3112~ r l r c o n l . 3 . F l q . 5b shows a t y p i c a l f r a c t u r e s u r - f a c e made o f two zone one prerfomlnant.1.v r e q u l a i - , t h e o t n e r p u c k e r e d a s can b e seen a t a h i g h e r m a g n l f 1cnt.19n lri F 1 q . Sc.

Phases

Cuz(T1 .A1 )4C A q (Cu l n sc T 1 sCu4 T i ( C u , A 1 ) 4 TlCu TlzCu a - T i

( T 1 ,A1 )3Cu L a t t i c e p a r a m e t e r s ( A )

a b C

1 3 . 9 12.08

5 . 9 1 0 . 8 5

4 . 6 0 4 . 7 3 1 1 . 4 3

4.07 3.12 4.52 3 . 1 1 2 . 3 6 2 . $ 5 5.92

4.46

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Tabl-e 2

T e n s l l e s t r e n g t h o f TA6V/A1203 and TA6V/ZrO?.

F i g . 5

-

( a ) F r a c t u r e s u r f a c e o f a TA6V/A1203 sample, ( b ) F r a c t u r e s u r f a c e o f a TA6V/Zr02 sample ( c e r a m i c p a r t ) , ( c ) H i g h e r m a g n i f i c a t i o n o f t h e m i c r o g r a p h shown i n ( b ) , ( d ) P e r p e n d i c u l a r s e c t i o n of t h e s u r f a c e f r a c t u r e ( m e t a l p a r t )

.

Metal/Ceramic

TA6V/A1203 TA6V/Zr02

Energy d i s p e r s i v e X-ray a n a l y s i s performed on t h e 7 u r f a c e o f t h e m e t a l p a r t o f t h e r u p t u r e d t e s t specimen i n d i c a t e s t h a t t h e puckered p o r t l o n o f t h e f r a c t u r e i s made o f Cu-Ti phases, as shown i n F l g . 5d. As f o r t h e predominantly r e g u l a r p a r t o f t h e f r a c t u r e , a n a l y s i s i n d i c a t e s f o r T i , Cu and A 1 c o m p o s i t i o n s s i m i l a r t o those o f phase " a " . The complementary p a r t o f t h i s f r a c t u r e on t h e ceramic p a r t o f t h e b r o k e n sample was a l s o a n a l y s e d , and t h e presence o f T i , C u , A 1 was d e t e c t e d . T h i s r e s u l t i n d i c a t e s t h a t t h e f r a c t u r e o c c u r r e d

n r ~ d n m i n a n t . 1 ~ w i t h i n ~ h a s e "a" i n t h e c l o s e v i c i n i t y o f z i r c o n i a .

T e n s i l e s t r e n g t h (MPa) 3 L 1 150 L 50 Number o f specimens

10 7

B r a z l n g t e m p e r a t u r e ( " C )

870 210

870 210

(7)

COLLOQUE

DE

PHYSIQUE

The i n t e r f a c e r e c j i o r i I n t h e T A S V / A ~ Z U J and TA6V/ZrO; brazentents 1 s v e r y c o m p l e x . and c o n s l s t s o f numerous l a y e r s o f varying c o m p o s i t i o n and thlcl.:

T h i s r e s u l t i n d l c s t e s a r e a c t l v l t y o t t h e b r a z e a l l o y w i t h b o t h t h e ceram and t h e t i t a n l u m a l l o y .

The r e a c t l v l t y o t t h e Cu-Aq-T1 b r a z e w l t h A1203 o r IrO, l e a d s t c t h e f o r m o f t h e C u ~ ( T i . A 1 ) 4 0 o ~ i d e phase. Such a r e a c t i o n 1 s n o t y e t w e l l d e f l n e d a thermodynamical p o i n t o t v l e w . N e v e r t h e l e s s , l t Can be assumed t h a t 7 1 s e q r e g a t e s f r o m t h e m o l t e n b r a z e t o t h e c e r a m l c s u r f a c e becaune o f l t s a t t l n l t y f o r oxygen and t h a t oxygen f r o m a l u m l n a or- z l r c o n l a i s dissolved t h e S r a z e . Thence I l s s o l v e d o x y y e n may r e a c t 4 1 t h t i t a n i u m t o p r o d u s e c ~ r ( - l , A l ) ~ O / 7 / . Such a compound may s e r v e a s a t r a n s l t l o n l a y e r and a w e t t 3 b l e s u r f a c e t h a t p r o m o t e s b o n d i n g between t h e c e i a m i c and t h e

r / \ t \ '

a The base t l t a n l u m a l l o y a c t s as a s o u r c e o f T 1 t o t h e b r a z e , l e a d l n q t o t formation o f C L I - T 1 l n t e r m e t a l l i c phdses. The existence o f T12Cu. TICU, T l ( C u , A 1 ) 4 and TixCu4 and 1 s i n good agreement w l t h t h e s t a b l e compounds p r e s e n t I n t h e TI-CU phase d l a g r a m /O/.

Concei-nlng now t h e t e n s l l e t e s t s , i t 1s a l s o worthwhile t o n o t e t h a t z1r.c seems t o accomodate t h e s t r e s s e s introduced b y t h e b r s z l n g p r o c e s s , l n c o n t , r a s t w l t h what was o b s e r v e d f o r TU6V!alumlna j o i n t s p r e p a i - e d w l t h a s l m l l a r p r o c e d u r e . The b e t t e r mechanical b e h a v i o u r o b s e r v e d w l t h 2 1 1 - c o r i l a consistent w i t h t h e s l m l l a r t h e r m a l e x p a n s i o n c o e f f l c l e n t s o f TASV and z l r c o n l a . We a l s o n o t e d a p a r t l a l t r a n s f o r m a t l s n o f t h e l n l t l a l t e t r a g o n a f o r m of z l r c o n l a l n t o a m o n o c l l n i c s t r u c t u r e . and i t i s w e l l known t h a t s t r n n s f o l - m s t ~ o n ~ n s r e a s e s t h e r e s l s t a n s e t o sracw. p r o p a g a t l o n i n Zr0-:9/.

5 - CONCLUSION

The s l f f e r - e n t i n t e r ' f a c l a l phases f o r m e d upon b~3211-1g o f T A C V t o Zr02 a n d t.o A l z O z were c t i a r a c t e r l r e d . The c h e m l c a l ~ n t e r a z t l o n c f t h e b r a z e w i t h t CRi-smlc r e s u l t s I n a C u > ( T l ,A1 ) 4 0 l a . / e r . A J , ) s c e n t t o t t ~ e base 1net;:il. a sequence o f (:U- TI l n t,ermet.5111~ b h a ~ e s 1s o b s e r v e d . 'The nlec;tiarflsal i > i - o p ~ ~ - o f t h e J o l r l t . 5 1.n the-,e t w o s y s t e m s a r e v e r y d l f f e r e i ? t . . I n t h e case o f t h e T A C V / I ; O , : j o l n t r . , a t e n s l l e s t t - e n s t h o f 150 MPa was measui-ed. T h l s v a l u e h l g t i 517ouyh f o r - C O n s l d e t - l n c ~ , i l > p l l c a t l o n o f t h e b r a r l n g p r c j c e d u r e t o r e a l

C ' , = 2 , -, t ell15 .

I)r- Z i - r ~ l n H . , J and \/ander P o o i ' t e n 1 ; .

.

S l l i d a t e s ~ r i d u s t r - l e l s 10 i l 8 ? 5 3 l ) 21 N~c:h,?,la::. M . G . arrd Mol-tlmer K A . . M a t . ' 3 c l . and Tech. 1. ( 1 9 C 5 ! 65'.

M1 r t ~ h n i - a 1-1. and t i ~ e b e l E . , W ~ l d . ~ : i q J . 10 ( 1386 1 43.

~ l u e l l e , - N . t I . and K n o t t H . W . . i i - a n s . o f t h e ME.^. So?

.

of A I M € 2 2 7 i l ' 7 C . kaufmsn M.J. and S h u l l R . D . , Met. T r a n s . A . 1 7 s ( 1 7 8 6 ) 575.

Pr;nrson W . E:. , tianbboolc o f Ci->'st,alloqi-aprili: D a t a f o r 1 n t e r m a t . a l l i c Pha.

z d . P . V l l l n , ' s and L . D . C a l ~ e r t , . ASM, M e t a l s P a r k , O h l o ( 1 3 E 5 ) .

f'e,,toc!;- C . . h i - b l e r F . a r J R e v c r j i e v s c h l A . , t c be p u b i l s h e d l n J . o f I t?e..seai-cl7 ( I a r i u a r y 1330)

.

M~rr-r-,s.~, . 7 . L .

.

Monoqra;oh S e r l e s on A l l o Fl?as€ Viaqt-ams ~ : Fhacje d l aqi-am t ~ r ~ a i - ; . t ~ t a n l u m a l l o y s , e d . J.1-. M u r r a y , ASM. M e t a l s P a r k , O h l o , p . C:!

( 1 ' 7 8 7 )

Hul-11e ! l . and lieuer- A.I-4.. S c l c n c e and Technri1og.y c,f Z l r c c n l , ~ I T , Abv.iricec. 1 r~ C ; e r ~ n t l . ~ s 1.2 ( 1 9 L 1 4 ) 14