The AI-Zr (Aluminum-Zirconium) System

8/18/2019 The AI-Zr (Aluminum-Zirconium) System

1/15

P h a s e D i a g r a m E v a l u a t i o n s : S e c t i o n I I

c h a n g e s o c c u r r i n g i n C a m ] 4 a f t e r m a r t e n s i t i c t r a n s f o r m a t i o n a t

1 3 0 * C . W i t h t h i s d i s t o r t io n , [ 8 9 B r u ] i n d e x e d a l l o f t h e r e f le c t i o n s

o f t h e p o w d e r p a t t e rn o f C a G a 4 . F o r s t r u c t u r al a n a l y s is , a s i n g l e

c r y s t a l w a s e x t r a c t e d f r o m a n 8 4 . 6 a t . % G a a l l o y . T h e n , 2 9 3

r e f l e c t i o n s w e r e u s e d t o r e f in e t h e s t r u c t u r e w i t h R = 0 . 0 5 7 . T h e

p a r a m e t e r s o f t h e m o n o c l i n i c l a t t i c e w e r e f o u n d a s a = 0 . 6 1 8 1

(1) , b = 0 . 61 30 (1) , c = 0 . 611 7 (2) nm , a nd 13 = 118 . 9 4 (2)* .

C i t e d R e f e r e n c e s

*43 La y: E La ve s , C rys ta l S t ruc ture of Ca G a 2, La G a 2, a nd Ce G a 2,

Naturwissenschaften. , 31, 145 (1943) in G e rma n. (Equi D ia gra m ,

Cry s Struc ture ; Exp erimen ta l)

52E va : R . M . Eva nc e a nd R . I. Ja f fe , Lo w Me l t ing G a l f ium A l loys ,

Trans.AIME, 194, 153-156 (1952). (Eq ui D ia gra m; E xpe r ime nta l )

* 6 5 B r u : G . B r u z z o n e , M X 4 C o m p o u n d s o f A lk a l in e E a r th M e t a l s w i t h

I I I B G r o u p E l e m e n t s, Acta Crystal logr . , 18, 1081-1082 (1965) .

(Equi D ia gra m , Crys S t ruc ture ; Exp e r ime nta l )

*66B ru: G . Bruz z one , B ina ry Sys te m s Ca -G a , Sr-G a , Ba -G a , B o l l

Sci. Fa c. Chim. lndustr. . Bologn a, 24, 113-13 2 (196 6) in Italian. (Equi

D ia gra m, Cry s S t ruc ture ; Expe r ime nta l ;# )

66K r i : P . I . K r ipya ke vic h , E .I . G la dyshe vski i , and D . I . D z ya na , B ina ry

In te rme ta l l ic Comp ound s of the BaA I4 Type Conta in ing G a l l ium,

Soy. Phys. Crystallogr., 10, 392-394 (1966) . (Equi Diag ram , Crys

Struc ture ; Experimenta l)

7 0 B r u : G . B r u z z o n e , S o m e I n te r m e t al l ic C o m p o u n d s M X 2 F o r m e d b y

Ca , Sr a nd Ba, Att i Acaa~ Nat . Lince i , Rend. Sc . Fis . Ma t. Nat ., 48,

235-241 (1970) in I ta l ian. (Equi Diag ram , Cry s Struc ture ; Ex -

pe r ime nta l )

78Bru:

G. Bruz zone , E. Francheschi , an d E M erlo, MsX 3 Inter-

me dia te Equi s Forme d by Ca , S r a nd Ba , J . Le ss -Com m on M e t ., 60 ,

59-63 (1978) . (Equi Diagram , Crys Struc ture ; Expe rimen ta l)

*79Pa l : A . Pa le nz ona a nd S . C i ra f ic i , The Y t te rb ium -G a l l ium Sys -

t e m, J . Le ss -Com m on Me t . , 63 , 105-109 (1979) . (Equi Diagram,

Cry s Struc ture ; Exp erimen ta l)

8 5 C h a :

M.W . Chase , J r . , C.A. D avies , J .R. Dow ney, J r ., D.J . Frur ip, R.A.

M c D o n a l d , a n d A . N . S y v e m d , J A N A F T h e r m o c h e m i c a l T a bl es ,

3rd ed., J. Phy s . Che m . Re f D ata , 14 (Suppl . 1 ) , pa r t 1 , 685-688

(1985). (Equi D ia gra m , The rm o; Com pi la t ion)

8SK im: S . G . K im , Y u. M. G r in ' , E . I. G la dyshe vski i , Equi Equi lib ri a in

t h e S y s t e m C a - G a - F e a t 6 7 0 K , D op. Ak ad . Na uk U k r.. RS RA , F i z . -

Ma t., Tekh., 1, 76-7 8 (1985) in Ukra inian. (Equi Diagram ; Cry s Struc-

ture ; E xpe r ime nta l )

85Yat: S.P. Yatsenko, O .M. Sich evich, Ya.P. Yarm olyu k, and Yu.M.

G r in ' , The Crys ta l S t ruc ture o f the Eu3G a 8 Com poun d, Dop . Akad.

N au k Ukr. . RS R B, Geol . , Kh int , Biol ., 7, 55-57 (1985) in Russian.

(Equi D ia gra m , Crys S t ruc ture ; Expe r ime nta l )

86 Co r: G . Cordier , H. Schafer , and M. Stel te r, Elec tron Defic ient

Co mp oun ds of Gall ium: Crysta l Struc ture of Ca3Gas, Z.Anorg.AUg.

Chem. , 539, 33-38 (198 6) in G e rm a n. (Equi D ia gra m , Crys S t ructure ;

Expe r ime nta l )

86For:

M. L. Foma s in i a nd M. Pa ni , Ca 28G a 11,a Struc ture with Th ree

Pypes of Coord ina t ion Polyhe d ra a round the G a l l ium A tom s , A c t a

Crystallogr., C, 42, 394~ (1986) . (Equi Diag ram , Cry s Struc ture ;

Expe r ime nta l )

86Mer:

E M e r lo a nd M. L . Fornas in i , The Pse udobina ry Sys te ms

SrA gl. xZnx, Ca Cul -xG a x a nd Ca Cul . xG e x a nd thei r U se for Te st ing

Struc tura l Maps, J . Le s s -Com m on Me t . , 119 , 45-61 (1986) . (Equi

D ia gra m, Cry s S t ruc ture ; E xpe r ime nta l )

89Bru:

G . Bruz z one , M. L . Fom a s in i , a nd E M e r lo , Re -e xa m ina t ion

of the Ca -G a Sys te m a nd C rys ta l S truc ture of Ca G a 4, a Mon oc l in ic

Dis tor t ion of the BaA14-Type, J . Le s s -Com m on Me t . , 154 , 67-77

(1989) . (Equi Diagram , Cry s Struc ture ; Ex perim enta l ; #)

*89F or : M . L . Fom a s in i a nd E Me r lo , The Crys ta l S t ruc ture of

C a l l G a 7 , Z . Kristallogr., 187, 111-115 (1989) . (Equi Diagram, Crys

Struc ture ; Experimenta l)

*Indica tes key p aper .

#Indic a te s pre se nc e of a pha se d ia gra m.

Ca-Ga evalua t ion contr ibuted by V.P. I tkin, Department of Meta l lurgy and Mater ia ls Sc ience , Univers i ty of Toronto, Toronto, Ontario M 5S 1A4, C anada and

C.B. Aieock, Center for Sensor Mater ia ls , Universi ty of Notre Dame, 114 Cushing Hall, Notre Dame, IN 46556. This work w as supported by a g rant f rom ASM

International. Literature searched hrough 1990. Part of the bibliographic search was provided by A SM International. Professor Alcock and D r. Itkin are the Alloy

Phase Diagram P rogram C ategory Editors for binary alkaline earth alloys.

T h e A I-Z r A l u m i n u m - Z i r c o n i u m ) S y s t e m

B y J M u r r a y

A l c o a T e c h n i c a l C e n t e r

a n d

A P e r u z z i a n d J P A b r i a t a

C e n t r o A t b m i c o B a r i l o c h e

Equilibrium iagram

T h e a s s e s s e d Z r -A 1 p h a s e d i a g r a m ( F ig . 1 ) i s b a s e d p r i m a r i l y o n

t h e w o r k o f [ 3 9 F i n ] , [ 5 4 M c p ] , [ 6 0 E d s ] , [ 6 2 E d s ] , [ 6 2 P o t ] ,

[ 8 3 S c h ] , a n d [ 8 4 K e m ] , a n d i n c l u d e s : ( 1 ) t h e li q u i d , L ; (2 ) t h e b c c

t e r m i n a l s o l u t i o n , ( 1 3 Z r) , n w h i c h A 1 h a s a m a x i m u m s o l u b i l i t y o f

2 6 a t. % a t 1 3 5 0 ~ ( 3 ) t h e c p h t e r m i n a l s o l i d s o l u t i o n , ( c tZ r ) ,

w h i c h s h o w s a m a x i m u m s o l u b i l i ty o f 1 0 . 5 a t .% A 1 a t 9 4 0 ~ ( 4 )

t h e i n te r m e d i a t e c o m p o u n d Z r3 A 1 w i t h t h e c u b i c A u C u 3 - t y p e

s t r u c t u r e , s t a b l e u p t o t h e p e r i t e c t i c t e m p e r a t u r e o f 9 8 8 ~ ( 5 ) t h e

h e x a g o n a l I n N i 2 - t y p e i n t e r m e d i a t e c o m p o u n d Z r 2 A I , s t a b le u p t o

t h e p e r i t e ct i c t e m p e r a t u r e o f 1 2 5 0 ~ ( 6 ) t h e t e t ra g o n a l c o m -

p o u n d Z r 5 A 1 3, i s o s t r u c t u r a l w i t h S i 3 W s , s t a b l e i n th e t e m p e r a t u r e

r a n g e f r o m - 1 0 0 0 t o 1 4 0 0 * C w h e r e i t d e c o m p o s e s p e r i te c t i ca l l y ;

( 7 ) t h e t e t r a g o n a l c o m p o u n d Z r 3 A I 2 s t a b l e u p t o t h e p e r i t e c t i c

t e m p e r a t u r e o f 1 4 8 0 ~ ( 8 ) t h e h e x a g o n a l c o m p o u n d Z r 4 A I3,

s t a b le u p to t h e p e r i t e ct o i d t e m p e r a t u r e o f - 1 0 3 0 ~ ( 9 ) t h e

J o u r n a l o f P h a s e E q u i l i b r i a V o l . 1 3 N o . 3 1 9 9 2 2 7 7


2/15

S e c t i o n I I : P h a s e D i a g r a m E v a l u a t i o n s

h e x a g o n a l G a 4 T i s - t y p e i n t e r m e d i a t e c o m p o u n d Z r 5 m l 4 s t a b l e

f r o m - 1 0 0 0 ~ t o 1 5 5 0 ~ w h e r e i t m e l t s c o n g ru e n tl y ; ( 1 0 ) t h e i n -

t e rm e d i a te c o m p o u n d Z r A 1 w i t h t h e o r th o r h om b i c B C r - t y p e

s t ru c tu re , s t a b l e u p t o t h e p er i t ec t o i d t emp era t u re o f 1 2 7 5 * C ; ( 1 1 )

t h e o r t h o r h o m b i c c o m p o u n d Z r 2 A 13 , w h i c h d e c o m p o s e s p e ri te c -

t i c a ll y at 1 5 9 0 ~ ( 1 2 ) t h e h e x a g o n a l M g Z n 2 - t y p e in t er m e d i at e

c o m p o u n d Z r A 1 2 , s t a b l e u p t o t h e c o n g r u e n t m e l t i n g t e m p e r at u re

o f 1 6 6 0 ~ ( 1 3 ) t h e t e tr a g o na l c o m p o u n d Z r A 1 3 , w h i c h m e l t s

c o n g r u e n t l y a t 1 5 8 0 * C ; ( 1 4 ) t h e f c c t e r m i n a l s o l i d s o l u t i o n , ( A 1 ),

w i t h a m a x i m u m s o l u b i l i t y o f 0 . 0 8 3 a t . Z r at i t s p e r it e ct ic

t e m p e r at u r e o f 6 6 0 . 8 ~

H o m o g e n e i t y ra n g es a re q u i t e re s t ri c ted f o r a ll o f t h e in t ermed i a t e

p h a s e s , a n d th e ir a c tu a l c o m p o s i t i o n s c o r r e s p o n d c l o s e l y t o t h o s e

c~

9

0

t

W e i g h l P e r e e n l A l u m i n u m

I0 EO 30 4(1 50 60 70 80 90 100

1660"C

1 8 5 5 ~ ~ .

1[;00 59

" ' . 1 4 8 0~ 1 5 5 0 ~ /

" ' . . " ' - . 1 4 0 0 ~ ( ~ ' ~ 1 4 8 5 ~1

H u o ' . . ' , 3 1 . ,, -

( , S Z r ) 2 ~ 1275"C

2 2 . 5 / 1 2 5 0 ~

e.l: i bl

1 0 0 0

12.5 8 C --~-I '

r - '

8 6 3 ~ C c o

0 0 0 ~ - ( ~ Z r ) % ~. ~o

~ 0 0

. . . . . I . . . . . r . . . . . . . . . . . . . .

10 20 30

Z r

'"

8 0 C

L 5 9 0 ~

N

6 6 0 . 8 C

, , ( A 1 ) ~

. . . . . . . 9 . . . . . . E . . . . . . . i

4 0 50 60

7 0

A t o m i c P e r c e n L A l u m i n u m

80 90

360.452~

100

A

2OOO

1855~

1800

1600

~ 1400

~ 1200

1 0 0 0

8 6 3 C

8 0 0

6 0 0

A t o m i c P e r c e n t , A l u m i n u m

1o Eo 30 40 50 60 70 80 90 100

~ ' , 86o~ L

~ 1480 0C 1550"C / {590~

5

~ / ~ -1400~C

1 20 30 4 50 60 70

Z r W e i g h t ] ) e t ' < e n t A l u m i n u n l

8 0

90

360.452~

I00

I

Fig. 1 Assessed Z r-ml phase d iagram.

2 7 8 J o u r n a l o f P h a s e E q u i l i b r ia V o l . 1 3 N o . 3 1 9 9 2


3/15


4/15

S e c t i o n I I: P h a s e D i a g r a m E v a l u a t i o n s

L ,

9

1 4 0 0

1300

1'200

1 t 0 0

I

{/O0

9 0 0

863~

~I00

700

G O 0

50O

" . . 1 3 5 0 o c " -

~ Z r ) + Z r 5 A 1 .

o o o o o o 9 1 4 9

~1250o C

o o o ~ x~

o o x x x

o o x x x x

Z r + Z r 2 A l

o o o o o o l / x x x x x

x ~ x g x x x x x

(~Zr)

o o o

o o o

o o o

0 0 0 o 0 0 . - d ' " o g 4 0 ~ O

9 9 z ~ z ~ z ~ z x z h z x z x

z

z~ zx ~ & z~

F aZr)+ZrsA1 ~

[.a

Zr

It 9

~ r s A I + Z r z A I

. . . . .. , i . . . . .. . ~ , , , - . .. .. , r . . . . .. . . . i . . . . .. . . . .. . . . .. .

5, 10 15 20 25 :~0

A / o t n i ( ' [ ~ ( : r ' f : C : l ~ ~ A [ 111/ 2] 1] 11 ] TI

5 4 M c p

O ( B Z r ) s i n g l e p h a s e

+ (aZr)+(flZr)

9 ( a Z r ) s i n g l e p h a s e

9 (flZr)+Zr5Al 3

x ( ~ Z r ) + Z r ~ A I

o (flZr)+ZraAl

( a Z r ) + Z r a A l

9 Z r 3 A I + Z r 2 A I

7 6 S e h

o ( B Z r ) + Z r 2 A l

(flZr)+Zr3Al

9 Z r 3 A I + Z r 2 A I

7 0 T i w

S o l u b i l i t y l i m i t

o f A I i n ( a Z r )

( l at t ic e p a r a m e t e r s )

F i g . 2 Z r - r ic h e x per i m e nt a l d a t a s upe r i m po s e d o n t he c o r r e s po n di ng bo unda r y l ine s s ho w n i n F i g . 1 .

~J

9

E P P P P S E S P S E S

0 t e m p e r a t u r e r a n g e a t w h i c h a t h e r m a l

a r r e s t w a s d e t e c t e d i n T . A . e x p e r i m e n t s 1660~C

/ / " / ~ ' "

e l t i n g t e m p e r a t u r e r a n g e o b t a i n e d ~

I t h r o u g h i n c i p i e n t m e l t i n g

d e t e r m i n a t i o n ~ \

1 6 0 0 . ' 5 9 ' ~

' i

1 5 5 0 o c 9 /' 9

9 i

1 5 0 0 " 9

14S O ~ J ] ~ ' '

" 9

' , , 3 ~ , ~ ~ , , ~ o c

] ' , , ' ,

1 4 0 0 o c x I

9

/

%

1 3 0 0 ] i [ i r

30 : 30 , 10 b0 60 70 SO 90

A I O l l l i C P ( ' I ' C r A h l l l l i l l l l ] q l

F i g . 3 A s s e s s e d Z r - A l l iqu i dus bo un da r y c o m pa r e d t o the e x pe r i m e nt a l da t a by [ 5 4 M c p] . E = e ut e c t ic , P = P e r it e c ti c , a nd S = s ing l e pha s e , i . e . t h e

a s - c a s t m i c r os t r uc tur e a t t he c o r r e s po nd i ng c o m p o s i t i o n .

2 8 0 J o u r n a l o f P h a s e E q u i l i b r i a V o l . 1 3 N o . 3 1 9 9 2


5/15

P h a s e D i a g r a m E v a l u a t i o n s : S e c t i o n II

microstruc ture and the single therm al arrest reported by [54Mcp]

for alloys with co mpositions 30.7 and 31 .4 at.% A1, respectively, we

adopt t he va lue 31 at.% A1 for t his eutecfic composition (see Fig. 3).

I n t e r m e d i a t e P h a s e s

Z r a A I

The existence of this compound, which is the Zr-richest inter-

mediate phase of the Zr-A1 sys tem, was repor ted by [54Mcp] and

confh'rned by several investigators [62Pot, 76Sch, 80Sch].

[55Keel determined the structure of Zr3AI to be of the cubic

CuAu3-type; th is result wa s corroborated by [62Pot].

Consistent with the observations of [54M cp] (metallography) and

[76Sch] (metallography, microhardn ess), th e temperature o f the

peritectoid reac tion (13Zr) + Zr2A1 ,-. Z r3AI is assessed to be 988

• 12 *C (see F ig. 2) . For the com position o f (13Zr) at this reaction,

we adopt the value 12.5 a t.% A I f rom the numer ical express ion

giv en abo ve for the (13Zr)/[(13Zr) + Zr2AI] bound ary.

Zr2A

The e xistence of this phase wa s reported b y [54Mcp] (metallog-

raphy) who also estimated the temperature of the peritectoid

reac tion (13Zr) + ZrsAI3 ,--* Zr2AI to be with in the limits 1200 to

1 300 ~ (see Fig. 2); the value adopted in Fig. I is 1250 • 40 *C.

For the compo sit ion of (13Zr) a t this react ion we take the value

22.5 a t.% AI fr om the expression giv en ab ov e for the (13Zr)/[(13Zr)

+ Zr2A1 boun dary.

[61Will a nd [62Pot] determ ined the crystal structure o f Zr2A1 to

be of the hexagon al InNiE- type.

Z r s A l a

Metal lographic and thermal analys is of as-cas t and annealed

samples allo wed [54M cp] to con clude that a stable intermediate

comp ound of composit ion Zr5A13 forms through the per i tectic

reaction L + Z r3Al 2 ~ Zr5A13 at 1395 • 10 *C. Al so, [54Mcp ]

suggested and [62Pot] (metallography, X-rays) later confirmed

that Zr5AI3 becomes metastable a t low tem peratures because of a

eutectoid reactio n ZrsAl3

-~-

Zr2Al

Z r 3 A l 2

at 1000 ~

For the composition o f the L phase at the L + Zr3Al2 .*-,. Zr5A 13

peritectic reaction, [54Mcp] sugg ested the approximate value 37

at.% A1. Ho wev er, this valu e implies a large difference between

the Zr3A12 and ZrsAI3 liquidus slopes, a feature which is

therm ody nam ically implausible. To attend this point, and com -

patible with the experimental observations ma de by [54Mcp] (see

Fig. 3) , we finally select 1400 *C for this peritectic temperature

and tentat ively adopt 35 a t .% Al for the cor responding composi-

tion of the L phase.

A d iscrepan cy existed regard ing the crystal structure of ZrsAl 3.

[59Wil2] sugge sted a hexago nal MnsSi3-type structure for this

com poun d. Howev er, [60Eds] and [62Pot] agree d that the crystal

structure of Zr5AI3 is of the tetragonal Si3W5-type and , moreover,

[60Eds] prove d that the conta min ation with interstitial impurities

stabilizes the MnsSi3-type structure. More recently, [83Sch]

(X-rays) co nfirm ed the tetragonal structure fo r the ZrsAl 3 phase

at temp eratures >800 ~ but proposed the hexagon al structure for

lower temperatures. Hen ce, accordin g to Fig. 1, the hexagonal

MnsSi3-type structure wo uld be a lo w- temperature, metastable

form of pure Zr5AI3. [83Sch] a lso m entioned that this hexagonal

form o f ZrsA13 seem s to be strongly stabilized by interstitial im-

purities. Co ntrary to these conclusions, [88Kim] (X-rays)

reported the hexa gon al structure in the range 800 to 1100 *C and

sugge sted that th is is the true stable structure o f ZrsA13; however,

their results might have been affected by the superficial con-

tamin ation of their samples.

Z r 3 A ] 2

The exis tence of this intermediate compo und was es tablished by

[54Mcp] by means of the metal lographic analys is of as-cas t

samples . Th ese authors used thermal analys is to determine that

Zr3AI2 form s peritectically at 1480 • 10 *C. [54Mcp] evaluated

the comp osit ion of L a t this per i tect ic reaction to b e- 39 at .% A1.

These va lues are those sho wn in Fig. 1. The crystal structure of the

Zr3AI2 com poun d was repor ted to be te tragonal by [60W ill] and

[62Pot].

Z r 4 A l 3 a n d Z r 5 A ] 4

[54Mcp] (metallography, therm al analysis) proposed the exist-

ence of an intermediate comp ound wh ose comp osit ion is c lose to

Zr4A13 and whic h melts con gruen tly at 1530 • 10 ~ This com-

position was later investigated by [62Pot] (X-rays, metallog-

raphy) wh o concluded f rom crys ta l st ructure determinat ions that

the cor rect composi t ion for this com poun d is ZrsA14 with a

hexa gona l crystal structure is otyp ic to that of Ga4Ti5. However,

[60Wi12] confirm ed the existence at low tempe ratures of a stable

hexa gon al structure w ith the co mpo sition Zr4A13. This last inter-

mediate phase w as a lso observed by [62Pot] who inves t igated the

structural cha nges o f alloys close to the com position Zr5A14upon

anneal ing around 1000 ~ The la ter authors then tentat ively

rationalized the available experimental informatio n by suggesting

the existence of (1) a peritectoid reaction Zr3A12 + Z rsAI4 *-,Zr4A13

at- 10 30 *C, and (2) a ZrsA14 ~ Zr4A13+ ZrA1 eutectoid reaction

at-1 00 0 ~ ( see Fig. 1).

The assessed temperature of 1550 ~ for the congruent melt ing of

ZrsA14 sho wn in Fig. 1 is co nsistent with the up per therm al arrests

found by [54Mcp] fo r alloys of composition 42.7 and 49.1 at.% A1

(see Fig. 3).

More recent work by [83Sch] (X-rays) and [84Kern, 85Kern]

(X-rays) conf irmed the features of the Zr-Al phase diagram

which ha ve been descr ibed above.

[54M cp] (metallography, thermal an alysis) indicated the existence

of a eutectic reac tion L.*-* Zr5A14

Z r 2 A 1 3

which occurs a t 1485

• 10 *C with a Lco mp ositio n of -4 9 at.% A1 (Zr5A14 s designated

as Zr4Al3 in [54Mcp]). How ever , [54Mcp] repor ted one and two

therma l arrests for alloy s containin g 51 and 4 9 at.% A1, respec-

tively (see Fig. 3) . Therefore, in Fig. I w e ad opt the value 51 at.%

A1 for this eutect ic compo sit ion; the same cho ice was made b y

[62Pot].

Zr AI

[54Mcp] (metallography, therma l analysis) exam ined alloys of

composit ion c lose to 50 a t .% concluding that a compound

ZrA1 form s at 1250 • 50 *C through the pefitectoid reaction

ZrsAI4 + Zr2Al 3 ~ ZrAI. Later work by [62Pot] (metallography,

X-rays), [83Sch] (X-rays), [84Kem] (X-rays), and [85Kern]

(X-rays) conf irmed the per i tectoid form ation of ZrA1. Because

Journa l of Phase Equil ibr ia Vol . 13 No. 3 1992 281


6/15

cj

cJ

Q

"F

9

9

c~

A { o m i c P e r c e n t Z i r c o n i u n l

o 5

o

o l r> o o 5 o :~ o : v ~ o 4 o 4 5 o 5 o 5 5 o ~

1 0 0 0 } . . . . . . . 1 ~ < . . . . . . I ,~ . . . . i . . . . ~ ~,L . . . . . r ~ . . .. . .. . ~ . . .. . .. i , . ~ 4 ~ . ~ . . . . l ~ m - • . . . . . . r , . . . . . . .

9 0 0 9

8 O 0

S

L

A3Z

7 0 0 - / ^

6 6 0 . 8 " C

.-

0 ~ 1 / . 2 8

6 0 0

5 0 0 "

4 0 0 J , ,

0

A I

X X A 4 -

A

AI)

A I Z r

. . . . . . . . i . . . . . . . . .

9 . . .. . .. . ~ . .. .. . T . . . . . . . . 1 . . . . . . i . . . . . . l *

. . . . .

0.;2 04 06 0 ~ I 12 14

W eigh t P e rcen t Z i r con i um

16 18 '~

Fi g .4 Al-r ich side of the Zr-AI phas e diagram. Curves are ca lculated fro m Gibbs energy funct ions.

8 .]

i

+

+ 4- q"


9 i . . . . . . . . . r . . . . . . . . . r . . . . . . . . .

0 ? O.8 0 9 1

1 0 0 0 / T

11 1 2 17, 14

Kelvin

Fi g .5 /M-rich side of the Zr-AI pha se diagram. Plot ted as In atom ic fract ion Zr) vs IO001T where T is the temperature in K.



7/15


the results o f [83Sch] sugge sted that ZrA1 should rem ain stable up

to 1300 *C, in Fig. i w e ado pt for the peritectoid temperature the

value 1275 , 25 *C as a comprom ise between the works of

[54Mcp] and [83Sch]. The crystal structure of ZrAI was deter-

mined b y [62Spo] to be of the or thorhom bic BCr- type.

Z r 2 A I 3

The exis tence of this com pound w as repor ted by [54Mcp] (metal-

lography, thermal an alysis). These authors also repo rted the exist-

ence of he peritectic reaction L + ZrAI 2 ,~- Zr2AI3 which occurs in

the temperature range 1585 to 1605 *C with a L composit ion of

-5 9 at.% A I. The peritectic temperature show n in Fig. 1 is 1590 *C

(see also Fig. 3). [61Ren] and [62Pot] established that the struc-

ture of Zr2AI3 is orthorhombic. [83Sch], [84Kem], an d [85Kem]

con firmed this result as well as the hig h temperature stability of

Zr2AI3.

Zr AI 2

This intermediate compound w as repor ted by [54Mcp] (metal-

lography, therm al analysis) to m elt con grue ntly at 1645 -,- 10 *C.

Ho wev er, this temperature str ictly corresponds to the therma l ar-

rest show n by a 68.8 at.% A1 sample. Th erefore, and as indicated

in Fig. 3, we s l ight ly mo dify the assessed melt ing temperature of

ZrA12 and tak e in Fig. 1 the va lue 1660 *C.

[59Wi11] (metallography, X-rays) corroborated the congruent

formation of ZrAI2 and determined its crystal structure to be of he

MgZn2-type. [62Pot], [83Sch], an d [84Kern] confirm ed the

structural res ults of [59Wi11].

Zr AI 3

This com poun d, which is the Al- r iches t intermediate phase of the

Zr-AI system, was f irst reported by [38Bra] (X-rays) w ho also es-

tablished th at its cryst al structure is tetragonal. W ork by [39Fin],

[62Pot], [72Oha], [83Sch], and [84Kem ] confLrrned he existence of

this phase. [54Mcp ] (thermal analysis) determined that ZrA13 me lts

cong ruently at 1580 • 10 *C.

[54Mcp ] determined the existence o fa eutectic reaction L ~ . ZrA12

+ ZrAI3 wh ich occurs in the temp erature range 1480 to 1500 *C

with a Lco mp osit ion of -73 .5 a t .% AI. However , these values im-

pose a steep slo pe on the I . /(L + ZrA13) bou nda ry at the eutectic

temperature, w hic h implies special characteristics fo r the thermo-

dy nam ic properties of the L phase. In turn, this steep slope also

constrains the slope of I . /(L + ZrAI2) to be steep at the eutectic

temperature. In order to min imize this featu re of the Zr-A1 phase

diagram, and be compatible with the presently available ex-

perimental inform ation [54Mcp], we ten tatively place in Fig. 1

the temperature of the L

.,--}

Zrml2

Zrml 3

eutectic reaction at

1500 *C and take for the L composit ion the mo re symmetr ical

value o f 72 a t .% AI . This las t composi t ion value is consis tent with

the single therma l arrest observe d by [54Mcp] in a sample con-

raining 71.3 at.% A I (see Fig. 3) . Furth er experime ntal investiga-

tion of this feature of the Zr-A1 phase diag ram is necessary.

A I R i c h A l l o y s

Zr is an impor tant minor a l loying addit ion to Al-based a l loys , and

therefore the Al-rich side of the diag ram up to 1000 *C is accu-

rately kno wn . Solubilities of Zr in both liquid a nd solid AI were

definitively determin ed by [39Fin]. The liquid solubilities w ere

determ ined fro m settling tests; the so lid solubilities w ere deter-

mined f rom resist ivi ty data and ver if ied by metal lography; the

peritectic temperature wa s determin ed by thermal analysis on

both heat ing and cooling. The assessed d iagram on the Al-s ide

(Fig. 4) is draw n f rom a thermod ynam ic calculat ion in which

Gibbs energies on the Al-s ide were op timized with respect to the

[39Fin] data. S olid (AI) forms from th e liquid by the peritectic

reaction L + ZrAI 3 ., -, , (AI) at 660.8 ~ The ma xim um solubility

of Zr in solid (AI) is 0.083 at.%; the com position of the liquid in

the peritectic equilibrium is 0.033 at.% Zr. The presen t thermo-

dynamic calculat ions ver ify the val idi ty of the di lute l imit

approximation for the A1 l iquidus and solvus up to 1000 *C, as

suggested by the l inear re lat ionship between the logar i thm o f the

solubility and 1/Tin K (see Fig. 5) .

Solubilities of Zr in liquid A1 were also measured by [64Chi]

using the settling techniqu e (equilibrated liquid was decan ted and

analyzed). T he results were reported in the form of the equation

loglo.~=A/T B

A = - 4 0 8 9 , 3 1 6

B = 0.896 • 0.305

w her eX is the a tom f ract ion of Zr, T is the temperature in K, and

the equation is valid between 660 and 850 *C.

Solid solubilities were also reported by [59Gla], [68Dri] , and

[83Kuz] ; parametr ic metho ds based on microhardness data were

used to determine the solvus compositions. The reported

solubilities from these studies are somewhat higher than the

selected values . The data are compared w ith the assessed boun-

daries in Fig. 4.

M e t a s t a b l e P h a s e s

[73Car] observe d the solub ility of A1 in (ctZr) to be exten ded to at

leas t 3 a t .% A I a l loy by quen ching f rom the s table (aZ r) f ie ld a t

850 *C. Accordin g to [78M ukl] and [78Muk2], fas t quenching

from the (13Zr) f ie ld of a 14 a t .% A I a l loy annealed a t 1150 ~

resulted in the formation of a cph supersaturated martensite

which includes D019 micro dom ains. [76Sch] reported the exten-

s ion of the (c tZr) phase up to composit ions 6 to 10 a t .% AI af ter

quenching f rom the Lph ase a l loys containing 22 to 27 a t .% AI .

[83Ban] (transmission electron microscopy, X-rays) investigated

the sequence o f t ransformations taking place in a 27 a t .% AI a l loy

dur ing rapid quenching f rom the l iquid s ta te . T hey foun d that the

eutectic form ation of ZrsAI3 is suppressed and that the structure

of the as-q uench ed sam ple consists of a diffusio n less-solidif ied

([3Zr) ma trix, athermal-~o particles and Z r2AI precipitates. T he

orientation and mo rpholo gy of the Zr2AI precipitates are closely

rela ted to the m atrix, sugg est ing a formation mechanism w hich

com bines a spin odal sepa ration o f ([3Zr) and a hyb rid displacive-

replacive orderin g reaction.

Disordering and e ventu al amorp hization of Zr3A1 by io n irradia-

tion we re reported b y [77How], [79How], and [87Reh]. [73W il]

studied the disordering effects of fast-neutron irradiation on

Zr4ml3.

As discussed un der the section ZrsA13, the hexag onal Mn5Si3-

type structure wo uld be a low te mperatu re metastable form o f the

Journal of Phase Equil ibr ia Vol . 13 No. 3 1992 283


8/15

S e c t i o n II P h a s e D i a g r a m E v a l u a t i o n s

Table 2 Zr-Al Crystal Structu re Data

Composit ion Pearson S p a c e Strukturbericht

P h a s e a t . A I s y m b o l g r o u p des ignation P r ot o t y pe Reference

(ctZr) ............................................ 0 to 10.5

([3Zr) ............................................ 0 to 26

Zr3A 1 ............................................ 25

Zr2A I ............................................ 33 .3

Z r s A I3 ........................................... 37 .5

Zr3A 12 .......................................... 40

Zr4A 13 .......................................... 42 .9

hP2

ci2

cP4

h P6

t/32

tP20

h P 7

Zr5A14 .......................................... 44 .4 hP 18

ZrA I .............................................. 50 oC 8

ZraA 13 .......................................... 60 oF40

ZrA12 ............................................ 66. 7 hP 12

ZrA13 ............................................ 75 t/1 6

(A1) ............................................... 99 .93 to 100 cF4

P6~mmc A3 M g [ M a s s a l s k i l ]

lm3m

A 2 W [ M a s s a l s k i l]

Pm3m L 1 2 A u C u 3 [55K ee , 62Pot]

P63/mmc B82 Ni2In [61Wil , 62Pot]

14/mcm D8 m

W s S i 3 [60Eds , 62Pot ,

8 3 S c h , 8 5 K e m ]

P42/mmm A12Zr3 [ 6 0 W i l l , 6 2 P o t ,

8 5 K e m ]

P6 . . . A13Zr4 [60Wi12, 62Po t,

8 5 K e m ]

P63/mcm G a a T i 5 [62Pot]

Cmcm Bf C r B [ 6 2 S po , 8 5 K e m ]

F d d 2 . .. A I 3 Z r2 [ 6 2 P o t , 8 5 K e m ]

P63/mmc

C 1 4 M g Z n 2 [59W il, 62Pot]

14/mmm D023

A I 3 Z r [ 3 8 B r a , 8 5 K e m ]

Fm3m A 1 C u [ M a s s a l s k i l ]

pure compound ZrsA13. Lat t ice parameters for this hexagonal

s t ructure are: a = 0.817 0 nm , c = 0.5655 n m [83Sch] . For the de-

pend ence of the la t tice param eters of hexag onal Zr5A13 wi th

oxy gen contam inat ion, see [88Cla] .

Am orphous Z r -Al f il ms were p rod uced wi t h i n t he eu t ec ti c com -

posi t ions 26 to 37 an d 47 to 55 a t .% AI by [75Gud] . Th is author

also reported the retention ofm etastab le (bZr) up to ~ 2 6 at .% A1.

Supersaturated sol id solut ions of Z r in (A1) containing as m uch as

3 a t .% Z r can be p r epa red by r ap i d so l i d i f i ca t i on [84Cha l ,

87Pan], and con side rable supersaturation is also achiev ed in

more d i l ut e cas t a l loys . Acoh eren t phase m Z rAl3 wi th t he o rde red

fcc L12 s t ructure [69Izu, 69Ryu , 72Nes, 87Vec] precipi ta tes as a

meta stable phase fro m the supersaturated solution. [87Vec]

measured t he com pos i t i on o fmZ rA13 by ene rgy d i spe rs i ve X- r ay

spect rometry; they foun d i t to form off -s toichiometry, a t 16.5

at .% Zr.

From studies wi th thin f i lms, [84Cha2] repor ted the precipi ta t ion

of metas table cubic-Zr2Al l l and or thorhombic-ZrA16 com-

poun ds af ter anne al ing o f supersaturated (A1) sol id solut ions co n-

ta ining -3 a t .% Zr . Fro m simi lar s tudies , [87Pan] con f i rmed the

resul t s of [84Cha2] and, in addi t ion, repor ted the format ion of

metas table cubic-ZrA1 and a vacancy -ordered phase based on

ZrA1. The metas table cubic-mZrA13 norma l ly obtained fol low ing

mel t quench ing was not obse rved by [84Cha2] or [87Pan].

mZrA13 is responsible for the ef fect ivene ssof Zr to cont rol recrys-

ta l lizat ion in A l-based al loys . It causes m ore uni form dis t r ibut ion

of dis locat ions and i t pins grain and subgrain b oundar ies [69R yu] ;

mZ rAl 3 i s very s table against coarsening an d against redissolu-

t ion [77Dah2] .

mZ rAl 3 a l so fo rms f rom t he me l t a s a p r i mary phase dur i ng r ap i d

sol idi f ication [72Oha, 77D ahl] . mZrA13 crysta ls act as nuclei for

sol idi f ication of (Al) , and Zr can thus work as a grain ref iner of Al

[77Dahl , 81Hor] . According to [86Pan] , sol idi f icat ion of

m Z r A l3 i s p r eceded b y ano t he r me t ast ab le phase dur i ng r ap i d

solidificatio n of a 9 8.1 at .% ALlalloy.

T he cohe ren t so l vus fo r p r ec i p i ta t ion o f m Z rAl3 woul d be va l u -

able for predict ing vo lum e f ract ions of dispersoid; h ow ever based

on the l i tera ture data , i t can o nly be crudely es t imated. TWo ex-

pe r i ment s t o de t e rmi ne t he co he ren t m Z rAl 3 so l vus have been

repor ted. [72Cer] m easured low tem perature res is t ivi ties of pure

AI , o f a 0 .5 a t .% Z r a l l oy quenched f rom t he h omogeni za t i on

t empera tu r e , and o f a 0 .5 a t .% Z r a l l oy quenche d f rom a l ong

precip itat ion annea l at 350 ~ As sum ing that the resist ivit ies are

s imply propor t ional to the am ount o f Zr in solut ion, a mat r ix com -

posi t ion of 0.049 at.% Zr was calculated. [86Zed] measured the

la t tice parameter o f the mat r ix phase a t 425 *C for two-phase (A1)

+ ZrAI3 and (A1) + mZrA13 al loys . Taking 0.0055 at .% Z r for the

equi l ibr ium solvus com posi t ion a t 425 ~ metas table solvus

com posi t ion of 0.008 at .% Z r a t 425 *C is calculated.

Thes e tw o result s are c lear ly inconsis tent. Th e lo wer solubil ity

[86Zed] i s prefer red becau se few er quest ionable assumptions are

requi red to interpret a measurement made at temperature . The

coheren t mZ rA13 so l vus was mo de l ed t he rmody uami ca l l y by

[88Sau] and as par t of this work. Al though very di f ferent

approaches were taken to the problem, the resul t s agree

reasonab ly wel l wi th ea ch other and w i th the [86Z ed] measure-

ment (see F ig. 6) . Detai ls o f the calculat ions and suggested cr i tical

expe r i ment s a re d i scussed in t he sec t ion T herm odyn ami cs o f

this evaluation.

r y s t a l S t r u c t u r e s a n d L a t t i c e

P a r a m e t e r s

Zr-A1 crysta l s t ructure data are sum ma rized in Table 2. Lat t ice

parameter data for (aZr) and al l the intermediate phases are

show n in Table 3. [62Eds] pointed out s imi lar i t ies between the

st ructures of Zr-A1 intermetal l ics and those of the s il ic ides and

borides. For exam ple, Zr4AI3has a o -pha se- l ike structure, related to

the s igma phases Ta2AI and Nb2A1. The Zr2Al s t ructure belongs

to the NiA s fam i ly of s i lic ide- like phases .

[80Stu] es t imated the ef fect of Zr o n the la t tice param eter of A1 as

a x ) = a (A1) + 0 .000507 x

whe re a i s the la t t ice parameter in nm and x the comp osi t ion of Zr

in at.%.

284 Journa l o f P hase E qui l i b r i a Vol . 13 No . 3 1992


9/15


T a b l e 3 Z r - A i L a t ti c e P a r a m e t e r D a t a a t R o o m T e m p e r a t u r e

Com position, Lattice param eters, nm

Phase at . AI a b c Comm ent Reference

(aZ r) ............................................. 0 0.32316 ... 0.51475 ... [M ass als kil ]

0.555 0.32309 . . . 0.51419 (a) [70Tiw]

2.800 0.32212 . . . 0.51365 (a) [70Tiw]

4.167 0.32140 . . . 0.51310 (a ) [70Tiw]

5.242 0.32103 . . . 0.51247 (a) [70Tiw]

f3 Zr . .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. ... .. .. 0 0 .3 60 90 . . . . . . > 86 3 * C [ M a s s al s k il ]

Zr3AI ............................................ 25 0.4373 . . . . . . . . . [55Kee, 62Pot]

ZrEA1 ............................................ 33.3 0.48 82 ... 0.59 18 ... [ 62P ot]

ZrsAI3 ........................................... 37.5 1.1042 ... 0.5393 (b) [62Pot, 85Ke rn,

88C1a]

Zr3AI ........................................... 40 0.7632 ... 0.6997 (b) [60 W ill, 85Ke rn]

Zr4A13 .......................................... 42.9 0.5430 ... 0.539 ... [60Wi12, 85K em,

60Eds]

ZrsAI4 ........................................... 44.4 0.844 ... 0.5785 (c) [62Pot, 85Ke rn]

ZrA .............................................. 50 0.3360 1.0890 0.427 ... [62Spo , 62Pot,

85Kem]

Zr2A13 .......................................... 60 0.9601 1.391 0.5578 ... [61Ren , 62Pot,

85Kern]

ZrA12 ............................................ 66.7 0.5280 ... 0.8747 ... [59W il, 85Ke m]

ZrAI3 ............................................ 75 0.4010 ... 1.730 ... [38Bra, 62Pot,

85Kern]

A I .................................................. 100 0.40496 . . . . . . . . . [M assalsk il ]

Note:

The listed values are averages from cited references. Samples previously heat treated at: (a) 850 *C, (b) 1100 *C, (c) 1100 to 1200 "C.

T a b le 4 E n t h a l p y o f F o r m a t i o n o f Z r -A I I n t e r m e d i a te C o m p o u n d s

Enthalpy

o f f o rm a t io n , k J /m o i

of atoms

Reference

Zr3AI Zr2AI ZrsA I3 Zr~AI 2 ZrsA I4 Z r A l Z r 2AI 3 Z r AI 2 Z r AI 3 __. C0mm_ent

[8 4K em ] . . . . . . . . . . . . . . . - 3 9 - 4 1 - 4 4 - 4 5 - 4 7 - 4 6 - 4 1 ( a)

[84Kem ](b) . . . . . . . . . . - 4 8 - 4 9 - 5 2 - 5 3 - 5 5 - 5 4 - 4 9 (a)

[76Ale] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -3 1 .*- ? --44 • 2 - 4 4 • 2 (c)

[88Boe] . . .. . .. . .. -50 --.65 -7 2 -7 5 . . . --83 -8 0 -7 2 -5 7 . . .

(a) Stand ard states at 298 K . Estimated errors are - ,- 4 kJ/mol o f atoms. (b) [84Kem] va lues corrected by present authors. S ee text. (c) Standard states at 1000 K.

he rmodynam i c s

E x p e r i m e n t a l D a t a

[ 8 4 K e m ] d e t e r m i n e d t h e e n t h a l p i e s o f f o r m a t i o n o f Z r5 A 13 ,

Z r 3 A 12 , Z r 5A I 4 , Z r A I , Z r 2 A 1 3 , Z rA 1 2 , a n d Z r A 1 3 . T h e s e a u t h o r s

m e a s u r e d t h e A 1 v a p o r p r e s s u r e o f a l lo y s f r o m p u r e Z r u p t o 7 5

a t . % A I i n t h e te m p e r a t u r e r a n g e 1 0 2 5 t o 1 4 0 0 ~ b y m e a n s o f a

K n u d s e n c e ll m a s s s p e c t ro m e t r i c t e c h n iq u e . W i t h a s s u m p t i o n o f

t h e v a l i d it y o f t he N e u m a n n - K o p p r u le , u s e o f t h e G i b b s - D u h e m

e q u a t i o n , a n d n e g l e c t o f a n y e f f e c ts o f p o s s i b l e n o n s t o i c h i o m e t r y

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

t h e fo l l o w i n g d e c o m p o s i t i o n r e a c t io n s w e r e d e t e r m i n e d b y

[ 8 4 K e m ] b y m e a n s o f t h e s e c on d - a n d t h i r d -l a w m e t h o d s :

} Z r 5 A 1 3 5

- , ~ Z r ( g ) + A l ( g )

Z r 5 A l - * 5 Z r ( [ 3 Z r ) + A l ( g )

5 Z r 3 A 1 2 ~ 3 Z r 5 A l 3 + A l ( g )

3 Z r 5 A 1 4 - - , . 5 Z r 3 A 1 2 + A l ( g )

Z r 2A 1 3 - - , 2 Z r A 1 + A l ( g )

2 Z r A 1 2 - -- , Z r 2 A l 3 + A l ( g )

Z r A 1 3 ---* Z r A I 2 + A l ( g )

T h e s e e n t h a l p y c h a n g e s w e r e i n t u r n u s e d b y [ 8 4 K e m ] t o c a l c u -

l a t e t h e s t a n d a r d e n t h a l p i e s o f f o r m a t i o n , A f H ~9 8, o f t h e c o r-

r e s p o n d i n g i n t e r m e t a l l i c c o m p o u n d s ; t h e r e s u l ts o b t a i n e d a r e

l i s t e d i n T a b l e 4 . [ 8 4 K e r n ] d i d n o t t a k e i n t o a c c o u n t t h e d i f -

f e r e n c e b e t w e e n t h e f r e e e n e r g i e s o f t h e l i q u id a n d s o l i d

p h a s e s o f p u r e A 1 a b o v e i t s m e l t i n g p o i n t ; t h e r e f o r e , w e

h a v e r e - c a l c u l a t e d t h e A f H O 98 v a l u e s a d o p t i n g f o r

ACp Cp



10/15

S e c t i o n II: P h a s e D i a g r a m E v a l u a t i o n s

qD

(D

E ~

A t o m i c P e r 'c e n L Z i r c : o m u m

1 0 0 0 ~ , 0 j0 5 . . . . . 011 . . . . . O ff ) - , 0 ~ . . . . ~ 25 . . . . . 0,i.3 ~ 6

7 0 0 i / / ' " . . . . . " ~ I A 1 , Z r b o un d ar ie ;6 1 .3 o c

500 , ' ' '

4 0 0

3 0 0

~ 0 0 . . . .

A1

I

I

0.2 0 4

W e i g h t , P e r ' c e n t Z i r c o n i u n a

Fig. 6 Roughestimate or the coherentmetastableL12phase mZrA l .

~0

fl :30

0 . . . . . . . .

T

10

x

, / 0

50

/

Calorimetry ~ t

o 7 4 E s i

~//'~

a 8 5 S u d ~

9 81Bat

-.- ittin g to i

c a l c u l a t e d values ~"

b y 8 8 B o e f o r /

equ ia tom ic ( m) /

and infinite

/

/

dilute solutions /

/

/

/

/

/

/

/"

/ /

/"

/

i"

10 :~ ) :$() d 0 ~ 00 710 810 5) 1 ]

r A [ o l l l i ~ : t ) ( ~ C f l ] [ A ] [ I I I I J l I I I I I I A ]

Fig.7 Enthalpyof formationof Zr A1 iquidsolutions.

286 Journal o f P hase E qui li bri a g o l 13 N o 3 1992


11/15


( li q ui d A I ) - C p ( fcc A1) , T> Tin, t h e v a l u e s p r o v i d e d b y t h e S G T E

data base . Th e cor rec ted va lues ob ta ined fo r k t 'H 398 a re l i st ed in

T a b l e 4 . F o r c o m p a r i s o n , s o m e c a l o r i m e t r i c v a l u e s f o r k f H

q u o t e d i n [ 7 6 A 1 c ], o b t a i n e d t h r o u g h a p r i v a t e c o m m u n i c a t i o n ,

a re a l so li s t ed in Tab le 4 . I t shou ld be m ent io ned tha t the t emp era -

t u r e ra n g e i n w h i c h [ 8 4 K e m ] s t u d ie d t h e r e a c t i o n

1

5Zr(13Zr ) + At (g )

Z r 5 A I 3

n a m e l y 1 2 2 0 t o 1 3 0 5 * C , m a y i m p l y t h e p r e c i p i ta t i o n o f t h e c o m -

p o u n d Z r 2 A I . T h i s w o u l d i n t r o d u c e s y s t e m a t i c e r r o r s i n t h e

t h e r m o d y n a m i c v a l ue s c o m p u t e d b y [ 8 4 K e m ] . A l s o , t h e l at er

a u t h o r s f o u n d a d i s c r e p a n c y f o r t h e v a l u e s o f t h e e n t h a l p y o f t h e

reac t ion

Z r s A l 4 5

,--,. ~Zr3 A12 + A l(g )

w h e n e v a l u a t e d b y m e a n s o f t h e s e c o n d - o r t h ir d - l a w m e t h o d s .

T h i s d i s c r e p a n c y m a y b e d u e t o a fa i l u re o f th e N e u m a n n - K o p p

r u l e a s s u m e d b y [ 8 4 K e m ] .

[ 6 1 S c h ] ( s o l u b i li t y m e a s u r e m e n t s ) d e t e r m i n e d v a l u e s o f A f G fo r

t h r e e i n t e rm e t a l l ic c o m p o u n d s , a s f o l l o w s :

A f G ( Z r4 A l 3 , s , 7 4 0 ~ = - 4 3 .1 k J / m o l o f a t o m s

A' fG (Zr2A13 , s , 740 ~ = -5 3 .5 kJ /m ol o f a tom s

A f G ( Z r A l 2 , s , 7 4 0 ~ = - 5 6 . 9 k J / m o l o f a t o m s

T h e e x p e r i m e n t a l p r o c e d u r e t e c h n i q u e u s e d b y [ 6 1 S c h ] w a s

cr i t i c ized by [Hul tg ren ,B] .

[ 7 4 E s i ], [ 8 1 B a t ] , a n d [ 8 5 S u d ] m e a s u r e d t h e e n t h a lp i e s o f m i x i n g

o f l i q u i d a l l o y s u s i n g c a l o r i m e t r i c t e c h n i q u e s . G o o d a g r e e -

m e n t e x i s ts a m o n g t h e r e s ul t s o f t h e s e a u t h o rs , w h i c h a r e

s h o w n i n F i g . 7.

W i t h a n e l e c t r o c h e m i c a l t e c h n i q u e , [ 8 2 B a t ] m e a s u r e d t h e a c -

t iv i ty o f A1

at

850 ~ in At - r i ch l iqu id a l loys . The so lub i l i ty l imi t

o f Z r i n l i q u i d A 1 p r o p o s e d b y [ 8 2 B a t ] a t t h is t e m p e r a t u r e i s - 1 .3

a t . Z r w h i c h i s m u c h l a r g e r t h a n th e a s s e s s ed v a l u e o f 0 .2 a t.

Zr ( see F ig . 4 ) . There fo re , the va l id i ty o f the resu l t s ob ta ined

by [82Bat ] a re ques t ioned and no t fu r the r cons ide red in th i s

eva lua t ion .

[86Sau] in i t i a l ly mode led and la te r r ev i sed [88Sau] Gibbs ener -

g i e s f o r t h e Z r - A 1 sy s t e m . T h e r e v i s i o n s b r i n g a b o u t c o n s i s t e n c y

w i t h S G T E t h e r m o d y n a m i c p r o p e r ti e s o f t h e e le m e n t s a n d

s o m e w h a t i m p r o v e t h e a g r e e m e n t w i t h t h e p h a s e d i a g r a m o n t h e

A l - s i d e . H o w e v e r , [ 8 6 S a u l a l r e a d y n o t e d t h a t t h e i r m o d e l i n g

c o u l d n o t re p r e s e n t t he e x p e r im e n t a l v a l u e o f 1 4 9 0 ~ f o r t h e

tempera tu re o f the L ~- , ZrA12 + ZrAl 3 eu tec t i c r eac t ion . Hence ,

[86Sau] sugges ted tha t the exper imenta l eu tec t i c t empera tu re i s

80 *C too low. I f the s ta ted exper im enta l eu tec t i c t em pera tu re i s,

a s we th ink , e ssen t ia l ly cor rec t , the Red l ich-Kis te r - type expan-

s i o n u s e d b y [ 8 6 S a u ] w o u l d n o t b e a d e q u a t e t o d e s c r ib e t h i s p a rt

o f t h e Z r - A l p h a s e d i a g r a m ( f o r e x a m p l e , a t e n d e n c y t o a s s o c ia -

t ion ma y ex i s t in the l iqu id phase ) .

F o r m o d e l i n g l o w - l e v e l Z r a d d i t i o n s t o m u l t i c o m p o n e n t A I a l -

loys , ve ry p rec i se resu l t s a re needed fo r the Al - r i ch l iqu idus and

so l idus , and the re fo re a se t o f Gibbs energ ies modi f ied f rom the

v e r s i o n o f [ 8 6 S a u ] w e r e c o n s t r u c t e d a s p a r t o f t h is w o r k . I n t h e

presen t ca lcu la t ion s , the Gib bs ene rgy o f a so lu t ion phase q9 s r ep -

resen ted as

a ~ X , 7 ) =

a 0 ( A l ) ( 1 - X ) + G 0 ( Z r ) X + R T [ X l n X + ( l - X )

I n ( l - X ) ] + ~ _ s P i ( 1 - 2 X ) A i ( 7 )

i

wh ere X i s the a to m f rac t ion Zr , G o i s the l a t ti ce s tab i l i ty o f the

pure e lemen ts , P i i s the i h Leg end re po lynom ia l , an d A i is an

e m p i r i c a l l y - d e t e r m i n e d c o e f f i c i e n t t h a t m a y b e a f u n c t i o n o f

t e m p e r a t u re . T h e A i is o p t i m i z e d w i t h r e s p e c t t o t h e c o m b i n e d

t h e r m o d y n a m i c a n d p h a s e d i a g r a m d a t a . A l l t h e i n t e r m e t a l l i c

p h a s e s , i n c l u d i n g t h e m e t a s t a b l e L 1 2 m Z r A l 3 p h a s e , a r e m o d e l e d

as s t r ic t ly s to ich iom et r ic . Pa ram ete r s o f the resu l t ing Gibbs ener -

gy fu nc t ions a re l i s ted in Tab le 5 .

F i g u r e 8 c o m p a r e s p a r t i al a n d i n t eg r a l e n t h a lp i e s o f m i x i n g o f th e

l iqu id f rom [74E s i ] , [82Bat ] , and [8 5Sud] wi th the resu l t s o f the

presen t ca lcu la t ions . T he va lu e o f the pa r t i a l mo la r en tha lpy , Hzr ,

i n t h e d i l ut e l i m i t i s d e r i v e d f r o m t h e p h a s e d i a g r a m t o g e t h e r w i t h

the ZrA13 en tha lp y o f fo rmat ion . T h is va lue i s cons i s ten t wi th the

sca t te red m easurements .

T h e c a l c u l a t e d p h a s e d i a g r a m i s c o m p a r e d w i t h e x p e r i m e n t i n

F ig . 4 , 6 , and 9 . Three fea tu res o f the ca lcu la ted phas e d iagra m a re

T a b l e 5 G i b b s E n e r g i e s o f th e Z r - A I S y s t e m J / t oo l J / K . m o l

Lattice stability param eters

G~ A1, L) = 10711-11.4728 T

Go (Zr, L) = 22 092-12.1340 T

GO A1,bcc) = 10 083 - 4 .8120 T

Go (Zr, bcc) = 4 3 10 - 3.7660 T

GO A1,cph) = 4 286 - 1.4070 T

GO Zr, eph) = 0

GO A1, cc) = 0

GO Zr, fcc) = 3 348

Solution phase interaction parameters

Phase Term Coefficient

L ................................ ZrAI* -15 7 186 + 66.89 6 T

L ................................ Zr*A I*P1 Zr-AI) 20 447

bcc ............................. ZrAI* -111 944 + 32.196 T

Zr*AI*P1 Zr-A1) -7332

cph ............................. ZrAI* -112 300 + 32.19 6 T

Zr*AI*P1 Zr-A1) -7332

fcc .............................. ZrAI* -11 1 692 + 40.71 0 T

Standard Gibbs energies ofintermetal l ic phases

G (ZrA13)= -44 298 + 11.590 T

G (mZrA13)= -40 300 + 11.590 T

G (ZrAlz)= -45 536 + 12.037 T

G (Zr2Al3)=- 45 200 + 11.448 T

G (ZrAI)=- 44 685 + 11.328 T

G (ZrsA14)= -43 127 + 10.426 T

G (Zr3A1 ) = -4 0 564 + 9.763 T

G (ZrsA13)= -39 000 + 9.372 T

G (Zr2A1)= -39145 + 11.026 T

G (Zr3A1)= -31767 + 9.666 T



12/15


0

2 X OX D D

4 0 0 0 0 i

6 0 0 0 0

- 8 0 0 0 0

1 0 0 0 0 0

- 1 2 0 0 0 0

1 8 0 0 0 0 . . . . . . . ~ n - . . . . . . . ~ . . . . . - T ~ . . . . . ' ' 1 . . . . . . . . . I . . . . . . . . . I . . . . . . . . . I , . . . . . . . . . I . . . . . . . . r

lO

~ 0

3 0

4 0 5 0 6 0

7 8

9 0

I

Z r A t o m i c P e r c e n t A l u m i n u m A 1

Fig .8 Partia l and integral enthalpies of mlx ing for the l iquid phase , according to experiments and to the present ca lculations.

G

1 8 5 5 ~ I

1 8 0 0

1

]1

1:~00

I

1O

J

~Zr)

W e i g h L Pcrcen A l u m i n u m

u

: ~o 3 0 4 0 0 0 o o 7 o 0 o ~ o ~ o o

. . . . . . . . . . . . . . ] 1 [ . . . . . . . . . . . . . I ] . . . . . . . . ~ 1 . . . . . . . .

T

. . . . . ~ 1 L - ~ [ , ] , ~ t ~

D 5 4 M o p . . . .

p h a s e l

9 5 4 Y l cp , t w o - p h a s e

a 5 4 M c p ,

s o l i d u s

1 6 0 8 ~ ~

1 1 7 0 ~

9 9 2 ~

o 6 j 7 }

1 /

I

0 10 k{O ;10 40

Z t ' A [ o m i ( :

b a b a

5 0

] ~ t " t ' C ' t ' l ? [

66 8~

t ; 0 7 0 ~ 0 9 0 1 0 0

A l t l l l l i l l l l l i t A I

Fig . 9 Zr-Al phase diagram calculated from the Gibbs energy functions l i sted in Table 5 .

2 8 8 J o u r n a l o f P h a s e E q u i l i b r ia V o l . 1 3 N o . 3 1 9 9 2


13/15


not ewor t hy . (1 ) C ompared t o t he l i qu i dus curves cons t ruc ted by

[54Mcp ] f rom the exper im ental data , the l iquidus of each inter-

metal l ic com pou nd near i t s congruen t mel t ing point i s ra ther fia t

and sy mm etr ical about s toichiometry. This featu re appears in a l l

calculat ions of the Zr-A1 system (e .g . [86Sau] and [88Sau]). A

be t t e r f i t t o t he curves p roposed by [54M cp] wo ul d r equ i r e a more

compl i ca t ed mode l f o r t he L . F ur t he r expe r i ment a l work i s

needed r ega rd i ng t he l iqu i dus o f t he Z r -A1 sys t em. (2 ) T he

t empera t u r e dependence o f t he ( ct Zr ) so l vus i s no t r eproduced by

the calculat ion. This feature a l so shows u p in the calculat ion by

[88Sau] . I t is probably a fa i lure of the models ; in the abse nce of l i -

quidus , sol idus , or enthalpy data for ( [3Zr) , severe const ra ints

mus t be i mposed on coe f f i c i en ts o f t he so l u t ion phase t o p r even t

s ingular it ies in the phase boun dar ies . (3) O n the A l- r ich s ide, the

agreement be t ween ca l cu la t ed d i agram and expe r i ment a l da ta i s

excel lent . In par t icular the calculat ion dem onst ra tes the consis-

tency am ong the per i tect ic tempe rature , the com posi t ions of l iq-

uid and sol id AI , and the enthalpy of mel t ing o f A1, as requi red by

the Gibb s-Ko nova lov re lat ionship.

Becau se there are only two ( incon sis tent ) data for the coherent

mZrA13 solvus , that boundary can only be calculated f rom a

predict ive model . [88Sau] used the Gib bs en ergy for the disor-

dered fcc (AI) solution, as de r ived f rom the s table equi l ibr ium

di agram, t o cons t ruc t t he G i bbs ene rgy o f t he o rde red L 12 phase

i~ the Bragg -W ill iams app roxim ation. He fou nd that m7_l'ml has a

congruent m el t ing point only 50 *C below that of the s table equi -

l ibr ium phase, i .e . , i t i s very near ly a s table phase. Calculated

metas table solvus com posi t ions we re repor ted to be 0.3 a t .% Zr a t

660 ~ and < 0.004 at .% Zr a t 200 ~

In the present work, i t was desi red to m odel mZrA13 as a l ine com -

pound in order to extend the calculat ions eas i ly to a var ie ty of

mul t i compon en t syst ems . It was a s sumed t ha t on l y an en t ha l py

term, and no ent ropy term, cont r ibutes to the Gibbs energ y dif -

ference betw een the s table and me tas table phases . This guaran-

tees that mZrA13 does not bec om e an equi l ibr ium phase a t high

t empera tu r e . T he en t ha l py d i ff e r ence be t ween t he t wo com-

pounds w as a s sumed t o a r i s e f rom t he co he rency o f mZ rA13 wi t h

the mat r ix. From the e las t ic proper t ies of AI and the es t imate by

[80Stu] for the comp osi t ion depend ence o f the la t t ice parameter ,

an e las t ic energ y of 2000 J /mo l was calculated.

Th e calculated metas table phase bo unda r ies are show n in F ig. 6.

The calculated solvus i s somewhat higher in Zr than the value

t aken f rom t he [86Z ed] work , bu t much l ower t han t he va l ue

repor ted by [72Cer] . T he calculated sol id so lubi l ity is lowe r than

predicted by [88Sau] , but a t high tem perature the l iquid solubi l ity

bec om es higher . F inal ly the calculated m etas table per i tect ic reac-

t ion occu rs a t 661.3 ~ wi th l iquid and sol id com posi t ions of 0.09

and 0.21 at .% Zr respect ively. Th e c alculated per i tect ic liquid

com posi t ion l ies wi thin the range w here the grain ref ining ef fect

of Zr begins .

Measurement of the metas table per i tect ic temperature dur ing

slow co ol ing o f very f ine droplets suggests i t se l f as a cr i t ical ex-

per iment for ref inement of the metas table phase boundar ies .

D i r ec t measurement o f t he m e t as tab l e so l vus shou l d i nvo l ve a

d i r ect quench f rom t he hom ogeni za t i on t empera t u re i n o rde r t o

avoid er rone ously high solvus temperatures due to s low kinet ics

of dissolut ion of mZrA13 previou sly forme d at lower tem perature .

[88Boe] presen ted a pheno me nolog ical calculation of AfH(Zr-A1)

for var ious com posi t ions . The resul ts obtained for the sol id and

l iquid phases are sho wn in Table 4 and F ig. 7 , respect ively.

C i t e d R e f e r e n c e s

38B ra: G. B rane r, Crystal Structure of Intermetall ic Alloys of

Aluminium with Titanium, Zirconium, Thorium, Niobium and Tan-

ta lum, Naturwissenschaflen, 26, 710 (1938) n Germa n. (Crys Struc-

ture; Experimental)

*39Fin: W .L. Fink and L.A . Willey, Equilibrium Relations in

Aluminium-Zirconium Alloys of Hig h Purity, Met. Technol., 1,

69-80 (1939). (Equi Diagram, Thermo; Experimental)

*54Mop: D.J. McPherson and M. Hansen, The System Zr-AI,

Trans.

ASM, 46, 354-374 1954). (EquiDiagram;Experimental; )

55Kee H.H . Keeler and J.H. M allery, Crystal Structure and Som e

Properties of the Compoun d, Zr3AI, J. Met., 2, 394 (1955) (Crys

Structure; Experimental)

59G la: V .M. Glazov, G. l_azarev,and Korolkov, The Solubil ity of Cer-

tain Transition Metals in Aluminium, Metalloved. Term . Obrab.

Met., 10,

48-50 (195 9). (Equi Diagram; Experimen tal)

59Wi11: C.G. Wilson, The C rystal Structure of ZrAI2, Acta Crystal-

logr., 12,

660-662 1959). (EquiDiagram, C rysStructure;Experimental)

59Wi12: C.G. Wilson, D. Sam s, and T.J. Renou f, Th e Crystal Structure

of ZrsA13, Acta Crystallogr. , 12, 947-948 (1959). (Equi Diagram,

Crys Structure; Experimental)

*60Eds: L. E. Edshammar and S. Andersson, Studies on the

Zirconium-A lurninium and I-Iaflaium-Aluminium Syste ms , A c t a

Chem. Scand. ,

14(1), 22 3-224 (1960). (Eq ui Diagram, Crys Structure;

Experimental)

60W ill: C .G. Wilson and EJ. Spooner, The Crystal Structure of

Zr3Al2, Acta C rystallogr. , 13,35 8-35 9 (1960). (Equi Diagram, Crys

Structure;Experimental)

60Wi12: C.G . Wilson, D.IC Thomas, and F.J. Spooner, The Crystal

Structure of ZraAl3,

Acta CrystaUogr. , 13,

56-5 7 (1960). (Equi

Diagram, Crys Structure;Experimental)

61Re n: T.J. Renouf, The Crystal Structure of Zr2AI3,

Acta Crystal-

logr., 14, 469 -472 (1961 ). (Equi D iagram, Crys Structure; Ex-

perimental)

61Sch: A. Schneider,H. K lotz, J. Stendel, and G. Strauss, On the Ther-

mochernistry of Alloys,

P ure A ppL C hem. , 2 ,

13-16 (1961). (Ther-

mo; Experimental)

61W il: C.G. Wilson and D. Sams, Th e Crystal Structureof Zr2Al, Acta

CrystaUogr., 14, 71-72 (1961). (Equi D iagram, Crys Structure; Ex-

perimental)

*62Ed s: L. Edsham mar, Crystal Structure nvestigationson th e Zr-A1

and Hf-AI Systems,

Acta Chem. Scand. , 16,

20-30 (1962). (Equi

Diagram; Experimental)

*62Pot: M. Potzschke and K. Schubert , On the Construction of Some

T4-B3 Homolog ous and Quasiho molog ous Systems. II. The Ti-A1,

Zr-AI, Hf-A1, Mo-A1 and Some Ternary Systems,

Z.MetaUkd. ,

53(8), 548-561 (19 62) in Germ an. (Equi Diagram , Crys Structure,

Therm o; Experim ental;#)

62Spo : F.J. Stx)onerand C .G. Wilson, The C rystal Structure of ZrAI,

Acta Crystallogr., 15, 621-622 (19 62). (Equi Diagram , Crys Struc-

ture; Experimental)

64C hi: P. Chiottiand P.E Woem er, MetalHydrideReactions. . Reactionof

Hydrogenwith Solutes n LiquidMetalSolvents, ./.

Less-CommonMet. ,

7,111 119 (1964). (EquiDiagram;Experimental)

68Dri: M.E . Drits, E.S. Kadaner, and V.I. Kuz'mina, Solubili ty of

Sil icon and Zirconium in Aluminium, lzv . Akad . Nauk, 1 , 102-105

(1968). (Equi Diagram; Experimen tal)

69Izu: O. Izumi and D. Oelschlagel, On the Decom positionof a Highly

SupersaturatedAI-Zr Solid Solution, Scr.

Metall., 3,

619-62 2 (1969).

(Meta Phases; Experimental)

Journa l o f P hase E qui l i b r ia Vol . 13 No . 3 1992 289


14/15

S e c t i o n I I P h a s e D i a g r a m E v a l u a t i o n s

69Ry u: N . Ryu m, Pre c ip i t a t ion a nd Re c rys ta l li z at ion in a n A t -0 . 5 w t . %

Zr -A l loy , Acta Metall . , 17, 269-278 (1969) . (Me ta Pha se s ; Ex-

pe r ime nta l )

70Tiw : S . N . T iw a r i a nd K . Tangr i, The Sol id Solubi li ty o f A lum inium

in c t -Z i r c onium, J . NucL Mater. , 34, 92-96 (1970) . (Equi Diagram;

Expe r ime nta l )

72C er: S. Ce res a~ M. Conserva , and P. Fiof ini, Recovery and Recrys ta l-

l izat ionofanAl-0.18wt.% ZrA lloy ColdWorkedat-196*C, Mater . ScL

E ng . , 9 ,19 -23

(1972) . (Me ta Pha se s ; Exp e r ime nta l )

72N e s : E . N e s , P re c ip i t a t ion of the Me ta s ta b le Cubic A l3Zr Pha se in

Subperi tec t ic A I-Z r Allo ys , A cta Metall . , 20,499-5 06 (1972) . (Meta

Pha ses ; Ex pe r ime nta l )

72O ha : T . O ha sh i a nd R . I c h ik a w a , A N e w Me ta s ta b le Pha se in Ra pid-

ly Sol id i fi e d A l -Z r A l loys , MetalL Trans. , 3 , 2300-2302 (1972) .

(Equi D ia gra m, Me ta Pha se s ; Expe r ime nta l )

73 Ca r: G.J .C. Carp enter and J .E Watters , Vacan cy Prec ipi ta tion in Zir-

c o n i u m A l l o y s , A c t a MetalL, 21, 1207-1214 (1973) . (Meta Phases ;

Expe r ime nta l )

73W ih C . G . Wi l son , N . W i lson , V . Joks imovic , a nd LA . We s tpha len ,

The Ef fe c t o f F a s t -N e ut ron I r r a d ia t ion onZr4A l3, A c ta

CrystaUogr.,

A , 29, 336-341 (1973) . (M eta Phases ; Experimenta l)

74E si : Yu.O. Esin, H. Bobro v, M. Pe trushevskii , and B. Ge l 'd, Enth a l-

p i e s o f F o r m a t i o n o f L i q u i d A l l o y s o f A l w i t h T i a n d Z r , lzv . Akad .

Nauk SSSR , Me t . , 5 , 104-109 (1974) in Russ ia n . (The rmo ; Ex-

pe r ime nta l )

75Gud: V.N . Gud zenko and A.E Polesya , Struc ture of Zirconium-

A lumim'um A l loys Ra p id ly Coole d f rom the L iqu id S ta te , Phys. Met.

Me taUogr ., 39 ,17 7-179 (1975) . (Meta Phases ; Exp erimen ta l)

75Sc h: E . M. Sc hul son , D . H . Mc C ol l , a nd V .C . L ing , Re f 'me m e nt o f the

Zr/ZrzAI Du plex Struc ture in Zr-7.6 to -9.0 wt.% A1 Ingo ts , Ch alk

Rive r N uc le a r La bora tor i e s , A EC L-5176 , Ju ly 1975 , Cha lk R ive r,

O ntar io, Ca na da . (Equ i D ia gra m ; Expe r ime nta l ; # )

76A ic: C . B . A lc oc k , K . T . J a c ob , S . Za dor , The rm oc he m ic a l P rope r -

ties,

Zircon ium: P hy s ico -Chem ica l P roper t ie s o f l t s C ompou nds

andAUoys, O. K ub a sc he w sk i , Ed . , A tomic Ene rgy Re vie w Spe c ia l

Issue No. 6, Interna t ional Atomic Energy Agency, Vienna (1976) .

( T h e r m o ; R e v i e w )

7 6 K u b : O . K u b a s c h e w s k i - v o n G o l d b e c k , P h a s e D i a g r a m s , Zir -

conium: Physico-Chem ica l Properties o f ts Compounds and A l loys,

O . K uba sc he w ski , Ed . , A tom ic Ene rgy R e vie w Spe cial I s sue N o. 6 ,

In te rna t iona l A to mic Ene rgy A ge n c y , V ie nna (1976) . (The rm o;

Re vie w )

76Sc h: E . M. Sc hul son a nd D . B . G ra ha m, The Pe ri te c to id Forma t ion of

Ordered Zr3A l , A c ta MetalL , 24, 615-625 (1976) . (Equi Diagram;

Expe r ime nta l )

77 Da hl : W. Dahl , W. Gruhl , W.G. Burchard, G. Ibe , and C. Dum itrescu,

Solidifica tion and Prec ipita t ion Behavior o f Al-Zr Alloys. I . The

Inf lue nc e ofZron the Solidification Stucture, Z. MetaUkd. , 68,121-127

(1977) in German. (Meta P hases ; Experimenta l)

77D ah2 : W. Dahl , W. Gru hl , W.G. Burch ard, G. Ibe , and C. Dum itrescu,

Solidifica tion and Prec ipi ta tion Beh avior of A1-Zr Alloy s . I I .

Prec ipita t ion Proce sses in Al-Z r Allo ys ,

Z. MetaU kd. , 68,

188-194

(1977) in G e rma n. (M e ta Pha se s ; Expe r ime nta l )

77H ow : L . M . H o w e a nd M. H . Ra inv i l l e , A Stud y of the I r ra d ia t ion Be -

ha viour o f Z r3A l , J . NucL Mater. , 68, 215-234 (1977) . (M eta Phases ;

Expe r ime nta l )

78 M uk l : P . Mu kho pa dh ya y and V . Ra m a n, D iscont inuous Pre c ip i t a-

t ion in a Martens i te ,

Metallography, 11,

481-485 (1978) . (Meta

Pha ses ; E xpe r ime nta l )

78Muk2: P. Mukhopadhyay, V. Raman, S. Banerjee , and R. Krishnan,

Formation of a D 19 Phase in Zirconium-Aluminium M artens i tes , J .

Mater. Sci., 13, 2066-206 8 (1978) . (M eta P hases ; Experimenta l)

79H ow : L . M. H o w e a nd M . H . Ra inv i ll e , The N a ture of Ir r ad iat ion-

Produc e d D a ma ge d Re gions in O rde re d Zr3A I , Philos. Mag. A,

39(2) , 195-212 (1979) . (Me ta Phases ; Experimenta l)

80S ch: E.M . Schulson, Furth er Ob serva t io ns of the Peri tectoid Trans-

forma t ion Z r + Zrz A l Zr3A l , Metall . Trans. A , 11,1918-1920 (1980).

(Equi D ia gra m; Expe r ime n ta l )

80Stu: H . C. S tumpf , A lc oa La bora tor i e s , unpubl i she d w ork (1980) .

(Crys Struc ture ; Expe rimen ta l)

81Bat: G.I . Batal in e t a l . Hea ts of Solut ion of Ti , Zr and B in l iquid Al,

Russ. Metall. , 1 ,61-63 (1981) . (The rm o; The ory)

81Hor: S. Hori , S. Sa ji , and A. Takehara , M etas tab le Phase and Gra in

Re f ine m e nt in Ra pid ly A l -Z r A l loys , . / .

Jpn. Inst . L ightM et. , 31(12),

793-797 (1981) . (Me ta Pha se s ; Expe r ime nta l )

82Bat: G . I . Ba ta lin , E . A . Be lobo rodova , V . V . N e ruba sc he nko , V . D .

G a lodc hka , a nd L . I . S lyuz ko , The rmo dyn a mic Prope r t ie s o f L iqu id

Solu tion in the A luminium -Zi rc onium Sy s te m,

Izv. V. U. Z. Tsvetn.

MetaU., 3 , 74-77 (1982) in Russ ian. ( 'Yhermo;Experlmentat)

83Ban: S. Ba ne r je e and R . W. Ca lm , A n O rde re d c o-pha se in the Ra pid ly

Solidified Z r-27at.% A l Allo y, Acta Metall . , 31(10) , 1721-1735

(1983) . (Meta Phases ; Ex perim enta l)

83K uz : G . M. K uz ne tsov , A . D . Ba r sukov , a nd M. I . A ba s , So lub il ity o f

Mn, Cr , Ti and Zr in Al in the Solid Sta te , Sov. Non-F errou s Met. R es.,

11 (1), 47-51 (1983). (Equi D ia gra m ; Expe r ime n ta l )

83S ch: J .C. Schuster, J . Bauer , and J. Deb uign e , Inves t iga t io n of

Phase Equil ibr ia Rela ted to Fusion Mater ia ls : I . The Terna ry Syste m

Zr -A i -N , J . Nucl. Mater., 116,13 1-135 (1983) . (Equi Diagram , Meta

Phases , Crys Struc ture ; Exp erime nta l)

8 4 C h a l : Z . A . C h a u d h u r y a nd C . S u r y a n a ra y a n a , A T E M S t ud y o f

D e c o m p o s i t i o n B e h a v i o u r o f a M e l t- Q u e n c h e d A l - Z r A l l o y , Metal-

lography, 17, 231-252 (1984) . (M e ta Pha se s ; Expe r ime n ta l )

84C ha 2: Z . A . Cha udh ury and C . Surya na ra ya na , T ra nsmis s ion

Ele ct ron Mic rosc opy S tud ie s o f a V a p our -D e pos i t e d A l -Zr A l loy ,

Ma ter. Sci. Eng., 67, 47-53 (1984) . (M e ta Pha se s ; Expe r ime nta l )

*84K e rn : R . J . K e ma t ic k a nd H .F . F ra nz e n , The rm ody na m ic S tudy of

the Z i r c onium-A lum inium Sys te m , J . So l id S ta te Che~ , 54 ,

226-234 (1984). (EquiD ia gra m, The rm o, Expe r ime nta l ; # )

85Kern: R. J . K e ma t ic k , H igh Te m pe ra ture The rm odyn a mic s of the

Z i rc onium-A lum inium Sys te m , Ph . D . The s i s , Iow a S ta te U nive r si ty

IS-T-1148, DE85 009230, 1985. (Equi Diagram , Cry s Struc ture ; Ex-

pe r ime nta l ;# )

85Sud:

V.S. Suda vtsova , G.I . Bata l in, and V.S. Tutev ich, Therm o-

dyna m ic Prope rt ie s o f Mol te n B ina ry A l loys in Sys te m s A l -Zr (N b,

M o ) , I zv. A kad . Na uk SSSR , Me t . , 5 , 185-187 (198~) in Russ ian.

(The rmo ; Expe r ime nta l )

86Pan: S. K . Pande y , D . K . G a ngopa d hya y , a nd C . Surya nara yana , A

Mic ros t ruc tura l S tudy of Ra pid ly Q u e nc he d A l -Z r A l loys , Z .

MetaUkd. , 77(1) , 12-16 (1986) . (Meta Phases ; Experim enta l)

86Sa u: N . Sa under s a nd V .G . R iv lin , The rm ody na m ic Cha rac -

te r iza t ion of Al-Cr, AI-Zr , and Al-C r-Zr Alloy Sys tem s , Mater . ScL

Techno l., 2, 521-527 (1986) . (The rm o; The o ry)

86Zed: M.S. Zedal is and M.E. Fine , Prec ipi ta t ion and Ostwald Ripen-

ing in D i lu te A l -ba se d-Zr -V A l loys , Me ta lL Trans .A, 17, 2187-2198

(1986) . (M eta Phases ; C rys Struc ture)

87Pan: S.IC Pandey, D.K. Gangopadhyay, and C. Suryanarayana ,

Me ta s ta b le Pha se s in V a p our -D e pos i t e d A 1-Zr Thin F i lms , Thin

SolidFilms, 146,

273-282 (1987) . (M e ta Pha se s ; Expe r ime n ta l )

87R e h: L . E . Re h , P . R . O ka m oto , J. Pe a r son , R . Bha dra, a nd M.

Grimsditch, Sol id-Sta te Am orph iza t ion of Zr3AI: Evide nce of an

Elas t ic Ins tabi l ity and Firs t-Order Phase Tran sform ation, Phy s . Rev.

Lett., 59(26), 2987-2 990 (1987). (Meta Phases; Experim ental)

87Vee: K.S. Vecchio and D.B. Wil l iams, Co nve rgen t Be am Electron

Diffrac t ion Study of Al3Zr in Al-Z r and Al-Li-Z r Allo ys , A c t a

Metall., 35(12) , 2959-29 70 (1987) . (M eta Phases ; Experimenta l)

88Bor

E R. de Boer , R. Boom, W.C.M. Mattens , A.R. Miedema, and

A.IC Niessen, Cohesion in Me tals , N or th H ol la nd , A ms te rda m , 367

(1988) . (The rmo; The o ry)



15/15


88Cla: N.J . Clark and E. Wu, Hyd rogen Absorption by MsX3 Phase

Zr-A1 Com pound s, J . Less-Common Met. 142 145-154 (1988).

(Meta Phases, Crys Structure; Experimental)

88K im: S .J . Kim, R.J . Kematick, S.S. Yi, and H.E Franzen, On the

Stabilization of ZrsA13 in the MnsSi3-Type Structure by Interstitial

Oxygen , J . Less-Common Met. 137 55-5 9 (1988). (Equi Diagram;

Experimental)

8 8 S a u :

N. Saunders, Department of Materials Science an d Engineer-

ing, University of Surrey, Internal Report INT-M SE-016 (1988).

(Equi Diagram, M eta Phases, Thermo)

*Indicates key paper.

#Indicates presence of a phase diagram.

Al-Zr evaluation contributed by J. Murray, Alcoa Tec hnical Center, Alloy TechnicalDivision, Alcoa Center, PA 15069 and A. Peruzzi and J.P. Abriata, Centro

At6mico Bariloche, Comisi6n Nacional de Energia At6m ica, 8400 S.C. de Bariloche, Argentina. The w ork was supported by ASM International. Literature

searched through 1988. Dr. M urray and Dr. Abriata are the Alloy Phase Diagram Program Category Editors for binary aluminum alloys and binary zirconium

alloys, respectively.

T h e L i-N L i t h iu m - N i tr o g e n ) S y s t e m

B y J . S a n g s t er a n d A . D . P e l t o n

E c o l e P o l y t e c h n i q u e d e M o n t r e a l

Equilibrium iagram

F i g u r e 1 s h o w s t h e a s se s s e d L i - N e q u i l i b r i u m d i a g r a m ; T a b l e 1

l is t s s pe c i a l p o in t s . T w o k n o w n c o m p o u n d s i n t h is s y s t e m i n c lu d e

L i 3 N , w h i c h m e l t s c o n g r u e n t l y , a n d L i N 3 , w h i c h d e c o m p o s e s

u p o n h e a t i n g . T h e p h a s e d i a g r a m h a s b e e n s t u d i e d o n l y i n th e i n -

te rva l be twee n L i and L i3N. One e u tec t i c invar ian t ex i s t s a t 180 .3

• 0 .1 *C. F igure 2 show s the de ta i l o f the eu tec t i c r eg ion . F igure 3

s h o w s t h e li q u i d u s b e t w e e n 1 8 0 a n d 7 2 7 ~ a s a p l o t o f l O g l0 ( a t.%

N) vs rec ip roca l t empera tu re .

T h e p h a s e r e l a t i o n s f r o m 0 t o 2 5 a t .% N w e r e d e t e r m i n e d b y

s o l u b i li t y [ 6 0 H o f , 6 7 A m , 7 5 A d a 2 , 7 5 Y o n ] a n d t h e r m a l a n a l y s is

[ 5 9 B o l , 7 6 H u b ] t e c h n i q u e s . A r e v i e w o f t h e e a r l i e r w o r k w a s

g i v e n b y [ 7 5 A d a 1 ] . E x p e r i m e n t a l p o i n t s f r o m t h e s e s t u d i e s a re

p l o t te d i n F i g . 1 to 3 . D a t a o f [ 5 9 B o l ] , [ 6 7 A m ] , a n d [ 7 6 H u b ] w e r e

no t t abu la ted b y the au thors ; the da ta po in t s sh ow n in F ig . 1 to 3

w e r e r e a d f r o m d i a g r am s .

Tab le 2 summ ar izes the exper imenta l cond i t ions and methods . The

so lub il i ty measurements o f [75Yon] and [75A da2] , over the range

f r o m 2 0 0 t o 4 5 0 * C , a g r e e w e ll , e v e n t h o u g h d i f fe r e n t e x p e r i m e n -

*Permanent address: San gster Research Laboratories, Suite 402,

3475 de la Montagne, M ontr6al Qufb ec, Canada, H3 G 2A4.

t a l t e c h n i q u e s w e r e u s e d b o t h t o a d d N a n d t o m e a s u r e t h e

so lub i l i ty l imi t a t L i3N sa tu ra t ion . Bo th s tud ies began w i th L i o f

> 9 9 .9 w t .% p u r it y , w h i c h w a s f u r th e r p u r i fi e d w i t h Z r , Y , o r T a

ge t te r s. L eas t - squa res f i t s in F ig . 3 to the da ta o f [75Yon] o r to the

da ta o f [75Ada2] gave nea r ly ind i s t ingu ishab le l ines . The l eas t -

s q u a r e s l i ne s h o w n i n F i g . 3 w a s o b t a i n e d f r o m f i t t in g t h e t w o s e ts

o f d a t a :

l o g 1 0 ( a t .% N ) = 3 .2 4 5 5 - 2 0 7 2 / T ( f o r T < 7 2 3 K ) ( E q 1 )

whe re T i s in Ke lv in .

F igure 3 sh ow s tha t th i s line , wh en ex t rapo la ted to 727 *C, passes

c l o s e t o t h e e x p e r im e n t a l p o i n t s o f [ 5 9 B o l ] . T h e s e a u t h o r s u s e d a

the rm al ana lys i s t echn ique to m easure the l iqu idus up to the mel t -

T a b l e 1 S p e c i a l P o i n t s o f t h e A s s e s s e d L i - N P h a s e

D i a g r a m

Com posit ions o f the

respect ive phases, Temp erature R eact ion

React ion at .% N C type

L ~ [3Li ................. 0 180.6

Melting

13Li~ o.Li ............. 0 -193 Allotropic

L---, ([3Li)+ Li3N ... 0.0 5 ~0 25.0 180.3 • 0.1 Eu tectic

L ~ Li3N ............... 25.0 813 • 2 Co ng rue nt

T a b l e 2 E x p e r i m e n t a l

C o n d i t i o n s f o r I n v e s t i ga t i o n o f L i -L i 3N P h a s e D i a g r a m

Temp erature Method of Determinat ion of

range, *C saturation saturation point Referen ce

180.2 o 180.5 .................................................................................. M etere dN2gas

200

to

450 ............................. ................................ ........................... M ete redN2gas

195 to 441 ........................................................................................ Ex ce ssLi3Nadded

250 to 450 ............................. ................................ ........................... Ex ce ssLi3Nadded

350 to 800 ............................................... ......................................... Ex ces sLi3Nadded

250 to 318 .............................. ................................ .......................... Ex ce ssLiaNadded

Thermal analysis [76Hub]

Measurem ent of electrical resistance [75Ada2]

N analysis by Kjeldahl [75Yon]

N analysis by Nessler reagent [60Hof]

Thermal analysis [59Bol]

Measurem ent of electrical resistance [67Arn]

The AI-Zr (Aluminum-Zirconium) System

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