报告题目：Atomistic modeling of the sliding behavior of {110} twist grain boundaries in a-iron

　　主 讲 人：杨金波　研究员（材料疲劳与断裂研究部）

　　时    间：1月21日（周二）下午 15：00

　　地    点：李薰楼 356 会议室

　　报告简介：

　　Lath martensite and upper bainite commonly appear in commercial steels. The interfaces between their variants are mainly {110} twist grain boundaries. On the other hand, screw dislocations dominate plastic deformation of body-centered-cubic single crystals at low temperatures. The reaction between different types of screw dislocations can also generate {110} twist grain boundaries, closely related with the formation of deformation bands. In this report, atomistic modeling by molecular dynamics has been used to simulate the mobility of various {110} twist grain boundaries in a-iron. It is found that the critical stress to initiate the boundary sliding is strongly dependent on the direction of applied loading and the misorientation between grains. The results are explained on the basis of the vector form of the Orowan equation and differential displacement maps of dislocation cores.

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