Abstract In this study, 1 2 ¯ 1 0 -oriented interfacial crack behaviors and mechanical properties of Mg bicrystal subjected to uniaxial tensile deformation are systematically studied by molecular dynamic (MD) simulation. According to the simulation results, the behaviors of 1 2 ¯ 1 0 -oriented crack associated with { 1 0 1 ¯ 1 } twin boundary (TB), { 1 0 1 ¯ 2 } TB and basal/prismatic (BP) interface show a strong dependence on the crystalline orientation of Mg. For the bicrystals with TB, the brittle and ductile fracture rely on the competition of dislocation emission and cleavage at the crack-tip under low temperature. The brittle-ductile transition can be observed with the increased temperature. Interestingly, the BP transformation dominates the initial plastic deformation for Mg bicrystal with BP interface which accompanies the boundary migration under tension. The boundary migration mechanism is revealed to influence on the interfacial cracking behavior and the correlative mechanical property of materials.

中文翻译：

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镁双晶12~10取向界面裂纹行为的原子学研究

摘要 本研究通过分子动力学(MD)模拟系统研究了单轴拉伸变形Mg双晶的1 2 ¯ 1 0 取向界面裂纹行为和力学性能。根据模拟结果，与{ 1 0 1¯ 1 }孪晶边界（TB）、{ 1 0 1¯ 2} TB和基底/棱柱（BP）界面相关的1 2¯ 1 0取向裂纹的行为显示出强烈依赖于 Mg 的晶体取向。对于含TB的双晶，低温下脆性和韧性断裂依赖于裂纹尖端的位错发射和解理的竞争。随着温度的升高，可以观察到脆-韧转变。有趣的是，BP 转变主导了镁双晶的初始塑性变形，BP 界面伴随着张力下的边界迁移。揭示了边界迁移机制对材料的界面开裂行为和相关力学性能的影响。