Description of the thermal vacancies in the CALPHAD method

Abstract

Thermal vacancies in solids have not been treated explicitly in the CALPHAD-type thermodynamic assessments, because it was considered that their contributions to the Gibbs energy were limited (even at the melting point). However, it is necessary for the third generation database for CALPHAD-type thermodynamic calculations. In this paper, it was proposed that an appropriate procedure to set parameters in the CALPHAD-type assessments to reproduce the temperature dependency of thermal vacancy in pure metals and solid solutions.