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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
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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
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8/18/2019 The AI-Zr (Aluminum-Zirconium) System
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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
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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
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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"
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
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.
2 8 2 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
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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
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
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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
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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
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
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 8 5
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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
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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
( 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
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 8 7
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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
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
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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
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
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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)
2 9 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
8/18/2019 The AI-Zr (Aluminum-Zirconium) System
15/15
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
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]