Self-diffusion of BCC transition metals calculated with MAEAM

The energy during the process of self-diffusion in BCC transition metals Fe, W, Mo, Cr, Ta, Nb and V has been calculated by using modified analytic embedded-atom method (MAEAM). For each kind of three diffusion mechanisms nearest-neighbor (NN), next-nearest-neighbor (NNN) and third-nearest-neighbor (TNN), the energy curve is symmetric and the maximum value of the energy appears at the middle point of the diffusion path. Determined mono-vacancy formation energy E1vf, migration energy E1vm and activation energy Q1v for self-diffusion agree well with available experimental data of NN diffusion and are better than those obtained by the analytic embedded-atom method (AEAM) and Finnis–Sinclair models. Compared the energies corresponding to three diffusion mechanisms, the NN diffusion needs the lowest activation energy (and thus the lowest migration energy). So that, the NN mono-vacancy diffusion is favorable in BCC transition metals.