Thermodynamic modeling of the Hf-Sn and Sn-Y systems

Based on experimental thermodynamic and phase equilibrium data, the Hf-Sn and Sn-Y systems have been modeled by computational thermodynamics using the CALPHAD method. The enthalpies of formation (Delta H-f) for Hf5Sn3, Hf5Sn4 and HfSn2 (-36.95, -38.79 and -27.96 kJ/mol-atom, respectively) obtained via first-principles calculations were used in the thermodynamic modeling. The solution phases including Liquid, (alpha Hf), (beta Hf), (alpha Y), and (beta Y) were modeled with the Redlich-Kister polynomial. The nine intermetallic compounds, i.e., Hf5Sn3, Hf5Sn4, HfSn2, Sn3Y5, Sn4Y5, Sn10Y11, Sn2Y, Sn5Y2 and Sn3Y, were described as stoichiometric phases. A set of self-consistent thermodynamic parameters for both Hf-Sn and Sn-Y systems has been obtained. The calculated results show a good agreement with the available experimental data. (C) 2012 Elsevier Ltd. All rights reserved.