Thermodynamic Assessment of the Cu-Ti-Zr System.
II. Cu-Zr and Ti-Zr Systems.

Abstract

The thermodynamic assessment of the Cu–Zr and Ti–Zr systems has been carried out in the frameworks of the CALPHAD method. The Gibbs energy of liquid phase of Cu–Zr system has been described by the ideal associated solution model. The excess Gibbs energy of liquid phase of Ti–Zr system and solid solutions of the Cu–Zr and Ti–Zr systems were expressed by models with Redlich–Kister polynomials. The Gibbs energy of intermetallic compounds of Cu–Zr system has been described by the enthalpy and entropy of their formation. The set of self-consistent parameters of models has been obtained taking into account phase equilibria information and data on thermodynamic properties of phases. The calculated phase diagrams of the systems and the obtained values of thermodynamic properties of phases are in good agreement with corresponding experimental information. The analysis of relative thermodynamic stability of the supercooled liquid alloys and competitive crystal phases of the Cu–Zr system has been carried out.