Development of Phase-Based Databases via CALPHAD Method for the Design of High-Entropy Alloys

Targeting for the design of high-entropy alloys (HEA), we developed a combined database integrating thermodynamic description, mobility, and molar volume for a series of transition metals using the CALPHAD method. In this paper, we demonstrated the successful application of this database in predicting phase relationships in the Co-Cr-Fe-Mn-Ni system. The predicted liquidus, solidus, and σ-solvus temperatures, as well as the fractions of the σ phase agree well with the experimental data. In particular, the predicted effect of each element on the stability of the σ phase was in line with experimental observations. By using a series of equiatomic alloys, we showed that this database can be used to understand the elemental diffusion behavior and thermal expansion in concentrated alloys in the Co-Cr-Fe-Mn-Ni system. In addition, we also demonstrated that property databases for calculating thermophysical properties, such as thermal conductivity and electrical resistivity, can also be developed using the CALPHAD method.