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Thermodynamic calculation of Nb-Ti-V phase diagram
Calphad Vol. 18. No. 1, pp. 71-79, 1994 Copyright 0 1994 Elsevier Science Ltd Printed in Great Britain. All rights resewed 0364-5916/94 $6.00 + 0.00
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM K.C. Hari Kwnar, P. Wollants. and L. De&y Department MTM Katholieke Universiteit Leuven de croyiaan 2 B-3001 Heverlee, BELGIUM
ilb-=ctt .
Phase equlllbrlum
ln Nb-Tl-V system is calculated using thermodynamic
descrlptlons of the lower-order systems. The thermodynamic descriptions of Nb-‘fl and NIB-V are obtained by optlmislng available experimental lnformatlon. The parameters for Ti-V are taken liom a recent assessment. Phase diagram of the
limiting
binaries.
liquidus
projection,
solldus
projection.
and
two
isothermal sections are computed.
Introduction Nb-‘ll-V system exhibits extended solid solublllty that offers the promise of elevated temperature strength. The alloy forms a continuous series of solid solutions above 1155 K (882 “C). The calculations presented here are expected to aid the on-going research on light metal base alloys. A crltical evaluation of the system was done by [SoEno). On the basis of the experimental results of [57Kor, 59Korl. he presented a solldus proJection. a llquidus projection and two speculative Isothermal sections at 973 K (700 “C) and 873 K (600 “C). Since there are only llmlted experimental data on thls system, it ls deslrable to calculate the phase diagram using the thermodynamic descrlptlons of the lower-order systems. In the present work thermodynamic descrlptlons of the limiting binaries TI-Nb and Nb-V are obtained by optlmlslng the avallabk experimental information. The thermodynamic parameters diagram
for ‘f&V are taken from a recent assessment by [SOSaul. l’he ternary phase
ls calculated
by comblnlng
the binary descrlptlons
Received on 17 May 1993 71
according
to the Mugglanu
K. C. H. KUMAR et al.
72
extrapolatton scheme 175Mugl. ‘Ihe liquidus projectton. solidus projection, and two isothermal secttons are thus calculated. The22nodynamic Model8 All stable phases (Liquid, BCC, and HCP) are modelled using the single-lattice random solution model. According to this the integral molar Gibbs energy of phase I$. ((I = Ltquid. BCC, HCP). of the ternary alloy is given by:
G;=
c
x? OGf +RT ~x’Znx’+‘“G; i=Ti,Nb,v ia.Nb,i
where “Gt are the Gibbs energies of the pure elements in the structural state Q and ‘“Go, Is the excess molar Gibbs energy. If we use the Redlich-Kister format I48Redl to represent the excess Gibbs
energtes of the limiting binartes. accordtng to Mugglanu extrapolation formula,
the excess Gibbs energy of the ternary alloy can be written as:
where,
The Redltch-Klster model parameters, ‘L~,j, are chosen
SU&
that they should satisfactorily
represent all the avatlable thermochemical and phase diagram data of the corresponding binaries. Stdlitier
Lattice
The most recent !3G’IE recommendations of data for pure elements [91Dtn] are used herc.TheseareWedinTabkl. Evaluation
of Solution Binary
Parameter8 Syrtum
and CalcuIation
TM’&
of Phase Diagrama
,Tl-V, and Nb-V
‘I&V system was recently assessed by [90&u].
Calculations of phase diagrams of
Ti-Nb and Nb-V are also reported in the ltterature: Tl-Nb [84Rud, 75Che. 78Kau. 87Murlj: Nb-V [77Mol, 79BalJ. However, the recently assessed latttce stabiltttes of Tl. V, and Nb are signUlcantly dUEant
&om those used in the above calculations. Hence a reassessment of the
thermodynamic descriptions of the binarks T&l% and Nb-V is desirable. Since there are no reliable
experimental
thermochemical
data
avatlabk
assessments rely mainly on the phase diagram data.
for
these
systems,
the
present
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM
TABLE :l.Lattice
Stability Expressions
for Nb, Ti, and V (J
73
14’~)
Source: [SlDh] 4
(OGL
-
“Gr)
, Nbbium (Nb) lattim Stability-ReferenceState: SCC
29761.555 -10.61641TT-3.060Q6x10-23T7
UQ
.............298.15
HCP
.............298.15 < T c 2750.00 K @
(OG:, -0($
) , Titanium(Ti) La&e
Stability- Refer-
State: HCP
6787.656 -65426/T+l.OQ6Q72T-l5535Th(T) +4.11413~10-~T~ -0.365519x108T3 .............298.15
5756.546 -52509M +3636Q641T -7.4305TyT) +9.363570x10-3T2 -1.046055~10~T~ .............1155.00
UQ
-26209QQO36T+35’.005667Th(T)
-155.262655~10~~
+12.254402x10sT3
.............1300.00 < T < 1941.W K 104639.72 -m
-340.070171T +40.9262461Th(T)
-6.20464Qx10-3T2+0.304747x10-6T2 ............. 1941.00 < T < 4000.00 K 0
("G$-oGy)
,vanadium(v)~stabilily-Refer~ staB:Bcc 20764.117-9.455552T-5.19136x10-22T7 ........._.._ 298.15
UQ 22072.353 -10.0646T-6.443Qx1031T-Q 2163.00 < T < 4000.00 K HCP
4000 +2.4T .............298.15
K. C. H. KUMAR eta/.
74
It-Nb System
‘fhls is a relatively stmple system without any intermediate phases or invariant reacttons. A ultlcal evaluaUon of the system was done by I87Murll. (64RudJ pointed out that this system shows a positive deviation from the ideal behaviour. There are no experimental data for liquidus. Solldus was lnvestlgated by (5lHan. 69Rud. 6QZak]. ustng incipient meltlng technique. The reported results show good agreement. HCP-solvus data reported by [51Han. Gllmg. 66Guz. 65Rau. 70Ronl also show reasonable consistency. However, there is considerable scatter In the BCC-transus data kported [SlHan. SlImg.
by
66Bro, 66Guz. 7ORon. 82Gusj. especially at higher Nb concentrations. This
could be attributed to the dlfkulty
in attaining the true equilibrium at low temperatures or
hnpurltles present in the alloys. Hence in the parameter optimisation more attention was paid to reproduce the transus data near the T&edge. ‘Ihe calculated phase diagram along with various experimental data Is shown in Fig. 1. The optimised parameters used in the calculation art II&d
in Table 2.
0
1
Ti
I
0.2
I
I
I
Atoxik4R&i0~
FIG.
1. Calculated
1
I
NY
lK-Nb
I
I
0.8 (xnb)
Phase
D&p-am
n-v system This system was critically assessed by [81Mur, 87Mur2j. (87Mur2j differs from [81Mur] with respect to a miscibility gap in the BCC phase. However, a recent experimental
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM
75
work by I89Fuml suggests that there is no such stable miscibility gap. In a recent thex-nmdynamic characttrlsatlon of the system by [908aul this fact was taken into consideration.The interaction paramettrs that are used to calculate the phase diagram (Fig. 2) are Wed in Table 2. According to the calculationsthe Liquid c) BCC azeotroplc minimum is at I887 K (1594 “cl, corresponing to x,=0.315. The m&a&able BCC miscibilitygap appears at temperatures below 841 K (588 T).
1667 E o 16005 1
BCC
& 51tsooG 1165
TABLE :2, So
ms (J ano+)
K. C, H.KUMAR et al.
76
2600
2800 Et 1 %hOO ok P % 2200
2000
shows complete solid solubtlily and exhtbits an azeotxopic minimum. The recent cjraluatkm of the system I89Smil Is based on the experimental solidus data of @4Wi&SQRudl. There are no data available for the liquidus, and the n4tability of the results of [54Wil] is doubted due to the disagreement with the presently accepted melting points of Nb and v. ‘l&is
system
In order to obtatn the solution parameters for Lk@d and BCC phases, a value of - 1800 J mol’ 1 was accepted as an initial estimate of Ol&, based on Mkdema’s prediction of enthalpy of mixing. This was further refined along with OLz! to reproduce the congruent minimum reported by @QRud).The calculated phase diagram along wtth experImental data is shown tn Ftg.3. me azeotropic melting occurs at 2131 K (1858oC). corresponding to Xv ~10.783.The solution parameters used in the calculations am listed in Table 2.
Using the thermodynamic descriptions of the binaries, phase equilibria ln the temary are predicted. Since HCP is not a stable phase in Nb-V system, it is assumed that the excess
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM
77
Gibbs energy of this phase in Nb-V as equal to that of the BCC phase. A liquidus proJection, solidus proJection.and two isothermalsecttonsare calculated.
At.c+mic Fraction
The liquidus projection Fig. 4) and solidus proJections (Fig. 5) exhibit similar features. There are no ternary reactions present. The hquidus and solidus temperatures increase with increase in Nb content. Existence of the azeotropic minfmum in l&V causes ah the liquidus and solidus isotherms between 1941 K (1668 “c) and 1867K (1594 “e) to originate and end on B-V side. However, the azeotropic mmimum in Nb-V introduces two branches in the solidus and hquidus lines between 2183 K (1910 “c) and 2131 K (1858 “c), one closing on Ti-V side and the other on Tl-Nb side. The sohdus and hquidus
Nb
temperatureincreases with increase in Nb content. The isothermal sections at 973 K (700 “c) @rig.6). and 873 K(600 “C) (Fig. 7) are similar in nature. The twophase field (BCC+HCP) extends from the Ti-Nb side to Ti-V side. The calculated solidus proJection and the isothermal sections are topologically different from those suggested by (SoErrol. Isothermal sections in the temperature range of 1155K (882%) to 1867K (1594oC) exhibit only the BCC phase.
--%.omic Raction IrIG.
6. h’b-IK-V
Sytewu
Nb
Cmqmted
(xllb) SolMu,
p*ofreh
The authors gratefully acknowledge the Unancialsupport offered to the Department MTM of the Katholieke Universiteit Leuven by the Flemish Ministry of Education and by the Bewxuch Council of Kathoheke Universiteit Leuven. fn the framework of “GOA-Action“.
K. C. H. KUMAR eta/.
78
L
0.2 1
Ti
?ffi
I48Redl: I5 IHan]:
I
Atomlo 6. N&N-I:
hi&a
ImdAamd
0. Red&h,
I0.2
Nb (X,.) Sedm
at 076 K (7OO’C)
?IG
7. N&T&-I:
hehtwd
Sdbn
at 676 K (606.C)
and A.T. Kister, Ind. Eng. Chem. ,40.345-348(1948).
M. Hansen, E.L. Kamen, H.D. Kessler, and D.J. McPherson, Trans. AIME. 19 I. 881-888(1951).
[54Wflj:
I-LA
Wilhem,
O.N.
Carlson.
and
J.M.
Dickinson.
Trans.
AIMEn 200.
QIS-918(1954). [57I&l:
1.1.Kornllov. and V.S. Vlasov, Zh. Neorg. Khim.. 2, 2762-2765( 1957).
[SQKorl:
1.1.Kornilov, and V.S. Vlasov. Russ. 3. Inorg. Chem., 734-738( 1959).
[GlInq$
A.G. ,I w.
Im@am,
D.N. Wffliams. Rk M-Cal
Wood,
Cwterlstics
H.R
Ogden,
and
of Hi&-Purity
R.I. Jaffee,
Titanium-Base
WADC Tech. Rep. 59-595, Battelle Memorial Institute (1961).
[64Rudl:
P.S. Rudman. Acta Metall.. 12. 1381-1388(1964).
[65Rau]:
Ch.J. Raub. and U. Zwicker, Phys. Rev., 137. Al42-Al43(1965).
(66Brol:
ARC.
Brown, and KS. Jepson. Mem. Sci. Rev. Met&.
63.575~584(1966).
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM
[66GUZ]:
LS. Guzd. E.M. Sokoloyskaya,and AT.
79
Grigor’ev, J. Moscow Univ., Chem..
21,406-49Q(l966). [69Rud]:
169ZakJ:
E. Rudy, “v
of Pw,
USAF Tech. Rep. AFML-TR-
65-2.
Part V. Wright Patterson Air Force Base(19691.
AM.
Zakhamv,
and AI.
V.P. Pshokin,
Elaikov, km. Tsvetn.
Met&..
t6);).
104-108( 1969). [7ORon]:
G.N. Ronami,
S.M. Kuznetsova. S.G. Fedotov, and KM.
Konstantinov. J.
Moscow Univ. Phys., 25,55-5761970). 175Chej:
D.B. Chemov, and A Ya. Shtnyayev, Russ. Metall., (51, 167-172(1975).
I75Mug.j:
Y.M. Muggianu, M. Gamblno, and J.P. Bras. J. Chlm. Phys., 72.83-88( 1975).
[77Mo&
V.V. Molokanov. D.B. Chemov, and P.B. Budberg. Russ. J. Phys. Chem.. 51. 1181- 1183(1977).
[78Kau]:
L. Kaufman, and H. Nesor, Calphad, 2,81-108(1978).
[79Ba&
S.S. Balakrishna. and AK. Ma&k Calphad, 3, 109-l 18(1979).
I8 lMur1:
J.L. Murray, Bull. Alloy Phase Diagrams. 2,48-55(1981).
[SZGus]:
L.N. Guseva, LX. Dolinskaya. Dold. Chem.. 334-337(1982).
(87Murlj:
J.L
Murmy, no
ASM In&national, [87Mur2]:
J.L.
Mumy,
J.L. Murray Ed..
of ~. Metals Park OH. lS8-194(1987).
J.L. Murray Ed..
"a,
ASM International, Metals Park OH, 319-3270987). [89Fumj:
W. Fuw.
[8QSmil:
J.F. Smith. and O.N. Carlson. “s
and H.M. Flower. Mat. Sci. Tech.. 5, 1172- 1175(1Q89). of Bv
1
J.F. Smith, Ed.. ASM International, Metals Park. OH, 161-1650989). [QOEno): [9OSaul:
M. Enomoto, J. Phase EZquilibtia. 12.369-362(1QQO). N. Saunders, University of Surrey Report to National PhyslcaI Laboratory, UK. Contract No. 022805/ 10B (1990)
[91Dhl:
AT. Dinsdaie, Calphad, 15.317-4250991).
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM K.C. Hari Kwnar, P. Wollants. and L. De&y Department MTM Katholieke Universiteit Leuven de croyiaan 2 B-3001 Heverlee, BELGIUM
ilb-=ctt .
Phase equlllbrlum
ln Nb-Tl-V system is calculated using thermodynamic
descrlptlons of the lower-order systems. The thermodynamic descriptions of Nb-‘fl and NIB-V are obtained by optlmislng available experimental lnformatlon. The parameters for Ti-V are taken liom a recent assessment. Phase diagram of the
limiting
binaries.
liquidus
projection,
solldus
projection.
and
two
isothermal sections are computed.
Introduction Nb-‘ll-V system exhibits extended solid solublllty that offers the promise of elevated temperature strength. The alloy forms a continuous series of solid solutions above 1155 K (882 “C). The calculations presented here are expected to aid the on-going research on light metal base alloys. A crltical evaluation of the system was done by [SoEno). On the basis of the experimental results of [57Kor, 59Korl. he presented a solldus proJection. a llquidus projection and two speculative Isothermal sections at 973 K (700 “C) and 873 K (600 “C). Since there are only llmlted experimental data on thls system, it ls deslrable to calculate the phase diagram using the thermodynamic descrlptlons of the lower-order systems. In the present work thermodynamic descrlptlons of the limiting binaries TI-Nb and Nb-V are obtained by optlmlslng the avallabk experimental information. The thermodynamic parameters diagram
for ‘f&V are taken from a recent assessment by [SOSaul. l’he ternary phase
ls calculated
by comblnlng
the binary descrlptlons
Received on 17 May 1993 71
according
to the Mugglanu
K. C. H. KUMAR et al.
72
extrapolatton scheme 175Mugl. ‘Ihe liquidus projectton. solidus projection, and two isothermal secttons are thus calculated. The22nodynamic Model8 All stable phases (Liquid, BCC, and HCP) are modelled using the single-lattice random solution model. According to this the integral molar Gibbs energy of phase I$. ((I = Ltquid. BCC, HCP). of the ternary alloy is given by:
G;=
c
x? OGf +RT ~x’Znx’+‘“G; i=Ti,Nb,v ia.Nb,i
where “Gt are the Gibbs energies of the pure elements in the structural state Q and ‘“Go, Is the excess molar Gibbs energy. If we use the Redlich-Kister format I48Redl to represent the excess Gibbs
energtes of the limiting binartes. accordtng to Mugglanu extrapolation formula,
the excess Gibbs energy of the ternary alloy can be written as:
where,
The Redltch-Klster model parameters, ‘L~,j, are chosen
SU&
that they should satisfactorily
represent all the avatlable thermochemical and phase diagram data of the corresponding binaries. Stdlitier
Lattice
The most recent !3G’IE recommendations of data for pure elements [91Dtn] are used herc.TheseareWedinTabkl. Evaluation
of Solution Binary
Parameter8 Syrtum
and CalcuIation
TM’&
of Phase Diagrama
,Tl-V, and Nb-V
‘I&V system was recently assessed by [90&u].
Calculations of phase diagrams of
Ti-Nb and Nb-V are also reported in the ltterature: Tl-Nb [84Rud, 75Che. 78Kau. 87Murlj: Nb-V [77Mol, 79BalJ. However, the recently assessed latttce stabiltttes of Tl. V, and Nb are signUlcantly dUEant
&om those used in the above calculations. Hence a reassessment of the
thermodynamic descriptions of the binarks T&l% and Nb-V is desirable. Since there are no reliable
experimental
thermochemical
data
avatlabk
assessments rely mainly on the phase diagram data.
for
these
systems,
the
present
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM
TABLE :l.Lattice
Stability Expressions
for Nb, Ti, and V (J
73
14’~)
Source: [SlDh] 4
(OGL
-
“Gr)
, Nbbium (Nb) lattim Stability-ReferenceState: SCC
29761.555 -10.61641TT-3.060Q6x10-23T7
UQ
.............298.15
HCP
.............298.15 < T c 2750.00 K @
(OG:, -0($
) , Titanium(Ti) La&e
Stability- Refer-
State: HCP
6787.656 -65426/T+l.OQ6Q72T-l5535Th(T) +4.11413~10-~T~ -0.365519x108T3 .............298.15
5756.546 -52509M +3636Q641T -7.4305TyT) +9.363570x10-3T2 -1.046055~10~T~ .............1155.00
UQ
-26209QQO36T+35’.005667Th(T)
-155.262655~10~~
+12.254402x10sT3
.............1300.00 < T < 1941.W K 104639.72 -m
-340.070171T +40.9262461Th(T)
-6.20464Qx10-3T2+0.304747x10-6T2 ............. 1941.00 < T < 4000.00 K 0
("G$-oGy)
,vanadium(v)~stabilily-Refer~ staB:Bcc 20764.117-9.455552T-5.19136x10-22T7 ........._.._ 298.15
UQ 22072.353 -10.0646T-6.443Qx1031T-Q 2163.00 < T < 4000.00 K HCP
4000 +2.4T .............298.15
K. C. H. KUMAR eta/.
74
It-Nb System
‘fhls is a relatively stmple system without any intermediate phases or invariant reacttons. A ultlcal evaluaUon of the system was done by I87Murll. (64RudJ pointed out that this system shows a positive deviation from the ideal behaviour. There are no experimental data for liquidus. Solldus was lnvestlgated by (5lHan. 69Rud. 6QZak]. ustng incipient meltlng technique. The reported results show good agreement. HCP-solvus data reported by [51Han. Gllmg. 66Guz. 65Rau. 70Ronl also show reasonable consistency. However, there is considerable scatter In the BCC-transus data kported [SlHan. SlImg.
by
66Bro, 66Guz. 7ORon. 82Gusj. especially at higher Nb concentrations. This
could be attributed to the dlfkulty
in attaining the true equilibrium at low temperatures or
hnpurltles present in the alloys. Hence in the parameter optimisation more attention was paid to reproduce the transus data near the T&edge. ‘Ihe calculated phase diagram along with various experimental data Is shown in Fig. 1. The optimised parameters used in the calculation art II&d
in Table 2.
0
1
Ti
I
0.2
I
I
I
Atoxik4R&i0~
FIG.
1. Calculated
1
I
NY
lK-Nb
I
I
0.8 (xnb)
Phase
D&p-am
n-v system This system was critically assessed by [81Mur, 87Mur2j. (87Mur2j differs from [81Mur] with respect to a miscibility gap in the BCC phase. However, a recent experimental
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM
75
work by I89Fuml suggests that there is no such stable miscibility gap. In a recent thex-nmdynamic characttrlsatlon of the system by [908aul this fact was taken into consideration.The interaction paramettrs that are used to calculate the phase diagram (Fig. 2) are Wed in Table 2. According to the calculationsthe Liquid c) BCC azeotroplc minimum is at I887 K (1594 “cl, corresponing to x,=0.315. The m&a&able BCC miscibilitygap appears at temperatures below 841 K (588 T).
1667 E o 16005 1
BCC
& 51tsooG 1165
TABLE :2, So
ms (J ano+)
K. C, H.KUMAR et al.
76
2600
2800 Et 1 %hOO ok P % 2200
2000
shows complete solid solubtlily and exhtbits an azeotxopic minimum. The recent cjraluatkm of the system I89Smil Is based on the experimental solidus data of @4Wi&SQRudl. There are no data available for the liquidus, and the n4tability of the results of [54Wil] is doubted due to the disagreement with the presently accepted melting points of Nb and v. ‘l&is
system
In order to obtatn the solution parameters for Lk@d and BCC phases, a value of - 1800 J mol’ 1 was accepted as an initial estimate of Ol&, based on Mkdema’s prediction of enthalpy of mixing. This was further refined along with OLz! to reproduce the congruent minimum reported by @QRud).The calculated phase diagram along wtth experImental data is shown tn Ftg.3. me azeotropic melting occurs at 2131 K (1858oC). corresponding to Xv ~10.783.The solution parameters used in the calculations am listed in Table 2.
Using the thermodynamic descriptions of the binaries, phase equilibria ln the temary are predicted. Since HCP is not a stable phase in Nb-V system, it is assumed that the excess
THERMODYNAMIC CALCULATION OF Nb-Ti-V PHASE DIAGRAM
77
Gibbs energy of this phase in Nb-V as equal to that of the BCC phase. A liquidus proJection, solidus proJection.and two isothermalsecttonsare calculated.
At.c+mic Fraction
The liquidus projection Fig. 4) and solidus proJections (Fig. 5) exhibit similar features. There are no ternary reactions present. The hquidus and solidus temperatures increase with increase in Nb content. Existence of the azeotropic minfmum in l&V causes ah the liquidus and solidus isotherms between 1941 K (1668 “c) and 1867K (1594 “e) to originate and end on B-V side. However, the azeotropic mmimum in Nb-V introduces two branches in the solidus and hquidus lines between 2183 K (1910 “c) and 2131 K (1858 “c), one closing on Ti-V side and the other on Tl-Nb side. The sohdus and hquidus
Nb
temperatureincreases with increase in Nb content. The isothermal sections at 973 K (700 “c) @rig.6). and 873 K(600 “C) (Fig. 7) are similar in nature. The twophase field (BCC+HCP) extends from the Ti-Nb side to Ti-V side. The calculated solidus proJection and the isothermal sections are topologically different from those suggested by (SoErrol. Isothermal sections in the temperature range of 1155K (882%) to 1867K (1594oC) exhibit only the BCC phase.
--%.omic Raction IrIG.
6. h’b-IK-V
Sytewu
Nb
Cmqmted
(xllb) SolMu,
p*ofreh
The authors gratefully acknowledge the Unancialsupport offered to the Department MTM of the Katholieke Universiteit Leuven by the Flemish Ministry of Education and by the Bewxuch Council of Kathoheke Universiteit Leuven. fn the framework of “GOA-Action“.
K. C. H. KUMAR eta/.
78
L
0.2 1
Ti
?ffi
I48Redl: I5 IHan]:
I
Atomlo 6. N&N-I:
hi&a
ImdAamd
0. Red&h,
I0.2
Nb (X,.) Sedm
at 076 K (7OO’C)
?IG
7. N&T&-I:
hehtwd
Sdbn
at 676 K (606.C)
and A.T. Kister, Ind. Eng. Chem. ,40.345-348(1948).
M. Hansen, E.L. Kamen, H.D. Kessler, and D.J. McPherson, Trans. AIME. 19 I. 881-888(1951).
[54Wflj:
I-LA
Wilhem,
O.N.
Carlson.
and
J.M.
Dickinson.
Trans.
AIMEn 200.
QIS-918(1954). [57I&l:
1.1.Kornllov. and V.S. Vlasov, Zh. Neorg. Khim.. 2, 2762-2765( 1957).
[SQKorl:
1.1.Kornilov, and V.S. Vlasov. Russ. 3. Inorg. Chem., 734-738( 1959).
[GlInq$
A.G. ,I w.
Im@am,
D.N. Wffliams. Rk M-Cal
Wood,
Cwterlstics
H.R
Ogden,
and
of Hi&-Purity
R.I. Jaffee,
Titanium-Base
WADC Tech. Rep. 59-595, Battelle Memorial Institute (1961).
[64Rudl:
P.S. Rudman. Acta Metall.. 12. 1381-1388(1964).
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