Thermodynamic Properties of Gd–Sn and Gd–Sn–Ni Melt Systems

Abstract

Enthalpies of mixing of liquid alloys are determined via isoperibol calorimetry for the Gd–Sn system throughout the range of concentrations at 1873, 1640, and 1510 K, and for the Gd–Sn–Ni system along the radial section with a constant ratio of atomic fractions of tin and nickel: x_Sn/x_Ni = 0.68/0.32 at 1873 ± 5 K up to x_Gd ∼ 0.25. It is found that the melts of the Gd–Sn system form with the release of a large amount of heat ($\Delta {{{H}}_{{\min }}}$= −68.4 ± 0.4 kJ/mol at x_Sn = 0.45). The calculations are performed using the geometric and analytical Redlich–Kister–Muggianu models of ΔH for melts of the ternary Gd–Sn–Ni system from similar data for binary boundary subsystems at 1873 K. The results show the minimum enthalpy of mixing of these ternary melts was established for the Gd_0.55Sn_0.45 alloy. It is shown that the experimentally investigated enthalpies of mixing of the Gd–Sn–Ni melts and calculated data using the Redlich–Kister–Muggianu model with ternary interaction parameter L = 500 kJ/mol agree satisfactorily with one another.