3D atomic-scale growth characteristics of {10-12} twin in magnesium

• 作者: Fusheng Pan Jing Zhang Xin Wan Xueyan Mo
• 来源期刊: 镁合金学报(英文)
• 学科: 工学
• 关键词: Molecular dynamics {10-12}twinning 3D growth Twin-related interfaces
• 年，卷（期）: 2019,（3）
• 页码范围: 474-486
• 页数: 13页
• 分类号: TG1

摘要

In this work,we carried out three-dimensional(3D)atomic-scale study on the growth characteristics of{10-12}twin in magnesium(Mg).The study was performed by MD simulations on Mg single crystals with an initial twin nucleus structures.A detailed atomistic analysis reveals that a stabilized 3D{10-12}twin nucleus is bounded by basal/prismatic(BP)interfaces,prismatic/basal(PB)interfaces,and{10-11}interfaces.Later,a{10-12}twin boundary(TB)occurs at the junction of the BP and PB interface with the growth of the twin nucleus.In this process,two twinning mechanisms are involved:a pure-shuffle mechanism in which{10-11}interface migration along the[11-20]direction is mediated by atomic shuffle,and a glide-shuffle mechanism in which BP/PB and{10-12}TB movements are realized by the migration of disconnections along the relevant interfaces.In addition,we systematically investigate the stress state associated with the activation of twinning,aiming to discover the intrinsic relationship of the elastic stress field to twin growth on an atomic scale.The results suggest that the elastic stress in the matrix is an important driving force for twin growth,much similar to what stress does for a crack.In addition,it is rather remarkable that the{10-11}interface has a greater ability to migrate than other interfaces,and this is thought to be a main factor for the rapid growth of a{10-12}twin.