Atomistic Modeling of Impurity Diffusion in the Grain Boundary of Σ3(112) in BCC Iron

The article presents an atomistic DFT analysis of the diffusion of chromium, nickel, and copper impurity atoms in bcc iron both in the bulk and along the Sigma 3(112) grain boundary. The contributions of the vacancy and interstitial mechanisms of impurity atom transfer are investigated, and the directions of preferential diffusion are determined. The temperature dependences of the diffusion coefficients are calculated taking into account the presence of the magnetic moment of the solution atoms, as well as the temperature dependence of the magnetization. The temperature dependences of the diffusion coefficients of nonmagnetic chromium and copper impurities in the bulk and along the Sigma 3(112) grain boundary are similar to the corresponding dependences for the self-diffusion of iron atoms. The dependences of the diffusion coefficients of nickel atoms are characterized by a stronger anisotropy of transfer along the grain boundary in comparison with the considered nonmagnetic impurities.