Diffusion characteristics and atomic mobilities for bcc refractory Mo–Ta, Mo–W, and Mo–Nb alloys

CALPHAD kinetics has gained rapid development in recent years, due to its wide applications in engineering novel alloys. In order to simulate the diffusion problems of interest, high-quality atomic mobilities are indispensable. Based on the thermodynamic descriptions for the Mo–Ta, Mo–W, and Mo–Nb binary systems, the atomic mobilities for such alloys are inversely parameterized in this work, including the mobility end-members as well as the interaction parameters. Due to the large experimental errors for diffusion characteristics of refractory alloys at high temperatures, the experimental data are quite scattered. However, this work allows such data to be carefully selected and a set of self-consistent atomic mobilities to be well established, which can be used to study diffusion-related characteristics for Mo-based refractory alloys.

► The atomic mobilities are explored using the CALPHAD approach.
► The temperature and concentration dependence are taken into consideration.
► Good agreements between the calculated and measured data are obtained.
► This work contributes to the design of novel Mo-based alloys.