Thermodynamics modeling of the Mg–Sr and Ca–Mg–Sr systems

Abstract

Thermodynamic modeling of the Mg–Sr binary system and the prediction of the Ca–Mg–Sr ternary system were carried out using the CALPHAD technique and a computerized optimization procedure. The thermodynamic descriptions of pure Mg, Ca, and Sr elements were taken from the literature. The first-principles calculations were performed using the computer code VASP based on the pseudo-potentials and a plane wave basis set for the ground state total energies of fcc-Ca, hcp-Mg, fcc-Sr, and all intermetallic compounds in Ca–Mg–Sr ternary system including the nine end-members of the laves C14 phase. Based on the experimental phase diagram and thermodynamic information, a set of parameters describing the Gibbs energies of the individual phases in this ternary system was obtained. The complete thermodynamic descriptions of the Mg–Sr binary system and the Ca–Mg–Sr ternary system were evaluated by this combined computational thermodynamics/first-principles calculations approach and shown good agreement with experimental data in the literature.