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

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.