A thermodynamic assessment of the Cd–Mg system

Abstract

On the basis of the experimental thermochemical and phase equilibrium data, the computational thermodynamic description of the Cd–Mg binary system is performed using CALPHAD technique. The solution phases, liquid and disordered Hcp_A3, are described as a substitutional model, and the excess Gibbs energies formulated with Redlich–Kister expression. The ordered phases, Cd3Mg, CdMg and CdMg3, are treated as the AB3 phase and modeled using four-sublattices. The order–disorder transformation between the AB3 and the Hcp_A3 phases is considered, so that the substitutional model for the Hcp_A3 disordered phase is extended into the four-sublattice model for the AB3 ordered phase. The thermochemical properties as well as the phase diagram of the Cd–Mg binary system are predicted. A set of self-consistent thermodynamic parameters has been obtained. The consistency between the calculated results and the reported data of both the phase equilibria and the thermochemical properties has been achieved.