Thermodynamic properties of magnesium alloys

Thermodynamic properties and their determination from first-principles and phonon calculations and CALPHAD (CALculation of PHAse Diagram) modeling are reviewed for Mg-based alloys and compounds, encompassing enthalpy, entropy, Helmholtz energy, Gibbs energy, heat capacity, isothermal and isentropic bulk moduli, anisotropic thermal expansions, and isothermal and isentropic elastic constants as functions of temperature, pressure and composition. Furthermore, various strategies based on first-principles calculations for the treatment of disordered phases are discussed, including the cluster expansion, special quasirandom structure (SQS), and partition function methods. Finally, other capabilities of the first-principles calculations are pointed out, such as: determination of Helmholtz energy for unstable phases; calculation of defect energies, such as vacancy formation energy, stacking fault energy, anti-phase boundary (APB) energy, and surface and interfacial energies; evaluation of diffusion coeffi cients in solid and liquid phases; assessment of creep properties, tensile and shear strengths, and solute strengthening due to alloying elements.