MOLECULAR DYNAMICS STUDY OF DEFORMATION AND FRACTURE OF BI-SEGREGATED COPPER BICRYSTALS

The microprocesses of deformation and fracture of Bi-segregated copper bicrystals Σ33 (545) 58.99°, Σ11 (323) 50.48° and Σ9 (212) 38.94° have been simulated by molecular dynamics in order to study the relationship between the grain boundary embrittlement (GBE) and grain boundary (GB) structure. It is shown that GBE is related to the segregated concentration and distribution of Bi atoms, while Bi segregation is re- lated to the GB structure. Due to their different structures, the bicrystals Σ33, Σ11 and Σ9 show an increasing propensity for Bi segregated concentration. So under the action of external force, Σ33, Σ11 and Σ9 show transgranular ductile, intergranular tearing and intergranular brittle fracture modes, respectively.