Application of the OpenCalphad software to optimization of the Au-Mg system

Ab initio calculations were used to determine the energy of formation, the molar specific heat at constant pressure of intermetallic phases, the change in the enthalpy of mixing of liquid solutions, and the phase equilibrium diagram for the gold-magnesium system. The calculations of the mixing enthalpy change of liquid Au-Mg solutions were conducted with the use of the VASP program and the density functional method (DFT), the parameterized pseudopotential functional of the general gradient approximation (GGA), the projector-amplified wave method (PAW), the ab initio molecular dynamics method (AIMD) and the Miedema model.

The calculated thermodynamic data, combined with existing literature on phase equilibria, were utilized to optimize the binary Au-Mg system. The thermodynamic optimization was performed using the OpenCalphad software. The resulting consistent set of Gibbs energies can serve as a reliable foundation for future research and development involving this binary system and for modeling the phase equilibria for the multicomponent systems with Au and Mg components.