Thermodynamic database integrated by electron theory and CALPHAD modeling

Computational thermodynamic approach based on the CALPHAD method has played a key role in materials science and engineering for these several decades as a bridge between experimental observations and theoretical prediction of phase equilibria. Within the same time frame, first-principles calculation based on the electron theory has progressed extensively and has interacted with the CALPHAD method. In this paper, we overview our recent research results on the calculation of thermodynamic properties such as enthalpy of formation for binary and ternary alloys at finite temperatures using electron theory as well as lattice vibration and cluster expansion method. Some examples of integrating those theoretical values comparable with experimental uncertainties and the CALPHAD methodology for construction of thermodynamic databases are presented.