The effect of Cr on He segregation and diffusion at Σ3(1 1 2) grain boundary in α-Fe

Abstract The effect of Cr on He segregation and diffusion properties at Σ3(1 1 2) grain boundary (GB) of α-Fe alloys was investigated using first-principles calculations. The results show that as the increase of Cr-segregated concentration at GB, the grain boundary energy first decreases to the minimum 0.42 J/m 2 and then increases to the maximum 0.49 J/m 2 . As for the effect of Cr on He segregation, the Cr atoms at GB increase effectively the He solution and segregation energies, suggesting that Cr atoms can inhibit He segregation. As for the effect of Cr on He diffusion, Cr can increase or decrease the He migration energy barriers along GB according to the Cr-segregated concentration at GB. It is worth noting that the He migration energy barriers along Cr-segregated GB are still considerably high, compared with He diffusion in Fe bulk. Consequently, the He diffusion along GB is inhabited at Cr-segregated GB in α-Fe alloys.