Comment on 'Diffusion mobilities for the B2-bcc phase in the Ni-Al binary system'

摘要

Wei et al. applied the B2-ordering model in CALPHAD to optimize the mobility parameters for the B2-bcc phase in the Ni-Al binary system from experimentally obtained diffusivities. Because the A2-bcc phase is metastable and does not exist in the phase diagram, the obtainment of its mobilities presents a challenge in the optimization process. It is pointed out that the mobilities given by Wei et al. for the disordered A2-bcc phase are not physically realistic. In addition, the simulation result for a diffusion couple is open to question according to the local equilibrium assumption.