Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys
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1
(333 6 55) 1 (21.39 6 0.20) ? 1 (1.29 6 0.36) ?
105 107 1 (23.89 6 0.40) ? 2 1 (24468 6 226) x T T
105x 1 (11,451 6 1178) x2 1 (211,431 6 1473) x3 1 (4053 6 826) x4 T
DHZr 5 (1 2 x)2
1
(2130.0 6 7.9) 1 (27.45 6 0.32) ?
1 (1.29 6 0.36) ?
104 107 1 (23.89 6 0.40) ? 2 1 (2928 6 108) x T T
105x 1 (5310 6 658) x2 1 (28189 6 1302) x3 1 (4053 6 826) x4 T
2
2
DH 5 x(1 2 x) aNi-Zr
aNi-Zr 5 (2130.0 6 7.9) 1 (27.45 6 0.32) ? 1 (6.43 6 1.82) ?
107 104 1 (23.89 6 0.40) ? 2 1 (2464 6 54) x T T
104x 1 (1769 6 219) x2 1 (22047 6 326) x3 1 (811 6 171) x4 T
for Cu-Ni-Zr (T 5 1565 6 5 K), DH 5 xCu xNiaCu-Ni 1 xCuxZr aCu-Zr 1 xNi xZraNi-Zr 1 xCuxNixZraCu-Ni-Zr
aCu-Ni 5 (11.1 6 0.6) 1 (1.1 6 0.1) xNi aCu-Zr 5 (242.9 6 5.2) 1 (244.2 6 10.3) xCu 1 (30.2 6 10.6) x5Cu aCu-Ni-Zr 5 (2570.4 6 28.8) 1 (3010.9 6 184.9) xZr2 (3349.8 6 268.6) x2Zr 1 (2942.8 6 55.7) x2Ni
I. INTRODUCTION
SINCE the Al-Cu-Ni-Zr system is a basis for the production of bulk amorphous materials by rapid solidification techniques from the liquid state,[1,2] it is of great scientific interest to determine the partial and the integral thermodynamic functions of liquid and undercooled liquid alloys. Such data, as was pointed out previously,[3,4] are important in order to understand their extremely good glass-forming ability in multicomponent metallic systems as well as for processing improvements. In order to measure the thermodynamic properties of the Al-Cu-Ni-Zr quaternary, it is necessary to have reliable thermochemical data for its constituent VICTOR T. WITUSIEWICZ, Guest Scientist, and FERDINAND SOMMER, Professor and Research Associate, are with the Max-PlanckInstitut fur Metallforschung, D-70174 Stuttgart, Germany. Manuscript submitted March 19, 1999. METALLURGICAL AND MATERIALS TRANSACTIONS B
binaries and ternaries first. In a series of articles, we have reported in detail the thermodynamic properties of liquid Al-Cu, Al-Ni, Cu-Ni,[5] Cu-Zr,[3] Al-Zr,[4] Al-Cu-Ni,[6] and Al-Cu-Zr[4] alloys. This article deals with the direct calorimetric measurements of the partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys and the heat capacity of liquid Ni26Zr74. In a subsequent article, we will present similar data for the liquid ternary Al-Ni-Zr and for the liquid quaternary Al-Cu-Ni-Zr alloys. II. EXPERIMENTAL The partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys were determined using a hightemperature isoperibolic calorimeter described previously.[7] The experiments were carried out under pure argon gas at atmospheric pressure. For the measurements, the thermocouples were made of Pt-6 pct Rh/Pt-30 pct Rh, and a thermopile VOLUME 31B, APRIL 2000—277
Table I. Heat Content of the Reference Material ZrO2 at 1565 6 5 K
Bath Metal
Amount of Bath (n), mmol
Cu
76.033
Cu
74.755
Al
84.211
Al
75.482
Al
71.400
Al
76.789
ˆ 21 DH 1565 298 5 84.1 6 2.0 kJ mol .
Added Substance
Added Amount (Dn), mmol
Area (F ), mV s mol21
Calibration Factor (W ), kJ mol21 mV21 s
Cu Cu ZrO2 Cu Cu ZrO2 Al
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