Cu Segregation at Σ5 Symmetrical Grain Boundary in α-Fe: Atomic-Level Simulations

Cu-rich precipitation is regarded as one of the main issues causing embrittlement of ferritic steels. In the present work, the Cu segregation at Σ5 {012} symmetrical grain boundary (GB) in BCC iron is investigated by combining Metropolis Monte Carlo and molecular statics approaches. The segregation driven energies of Cu clusters decrease with increasing the distance from GB and also depend on the cluster size. The length scales associated with Cu segregation at GB are determined. All these results indicate that Cu atoms prefer to segregate at S5 GB, which may account for the embrittlement of ferritic steels. The present results provide important knowledge to understand the detailed mechanisms of Cu segregation at GB and also the possible effects on mechanical properties of α-Fe.