Grain boundary segregation in low Cr Fe-Cr alloys: The effect of radiation induced vacancies studied by metropolis Monte Carlo simulations

Radiation damage may modify the segregation state and phase separation conditions in Fe-Cr alloys with compositions and temperatures of technological interest. We use Metropolis Monte Carlo simulations to study segregation effects at the best stable variant of the Σ = 5 (2 1 0) grain boundary, in the 5-10 at.% range of Cr composition. The role of irradiation induced vacancies in segregation is discussed. At a low Cr composition, an oscillatory Cr segregation profile is evidenced in the vicinity of the boundary. Under specific conditions, Cr ordering is observed close to the boundary. The correlations between such ordering and local stress is discussed. The binding energy of vacancies to specific sites of the grain boundary is found to be positive and the interplay between Cr segregation and the clustering of vacancies at the boundary is discussed.