ABSTRACT Molecular dynamics (MD) are employed to study the plastic deformation mechanisms of nanotwinned (NT) Mg with different twin boundary (TB) orientations under uniaxial tension. The orientation effect on the plastic deformation mechanisms of NT Mg is discussed. When the uniaxial tension is applied perpendicular to the TB plane, the emission of basal partial dislocations (BPDs) dominates the plastic deformation. The BPD-TB interaction and the gradual loss of coherence of TBs contribute to the ductility of NT Mg. With the increasing of the TB orientation angle (α), the twining dislocations (TDs) nucleate at the TB due to the shear component on the TB plane, the basal-dislocation-governed deformation transfers to the twinning-dislocation-governed deformation. The gliding of TDs along the TBs causes the migration of TBs and the subsequent detwinning. An obvious strain hardening is observed after the detwinning due to the disappearance of TBs.

中文翻译：

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不同孪晶界取向的纳米孪晶Mg的塑性变形机制：分子动力学模拟

摘要 采用分子动力学 (MD) 来研究单轴拉伸下具有不同孪晶界 (TB) 取向的纳米孪晶 (NT) Mg 的塑性变形机制。讨论了取向对 NT Mg 塑性变形机制的影响。当垂直于 TB 平面施加单轴张力时，基底部分位错 (BPD) 的发射主导了塑性变形。BPD-TB 相互作用和 TB 相干性的逐渐丧失有助于 NT Mg 的延展性。随着TB取向角（α）的增加，由于TB平面上的剪切分量，孪晶位错（TD）在TB处成核，基底位错控制变形转变为孪晶位错控制变形。TD 沿 TB 的滑动导致 TB 的迁移和随后的解缠。由于 TBs 的消失，在去孪晶后观察到明显的应变硬化。