论文标题
限制MG中的速度和跨气位
Limiting velocities and transonic dislocations in Mg
论文作者
论文摘要
为了准确预测材料的机械响应，尤其是在高应变速率下，重要的是要考虑这些机制中的脱位速度。在这些极端条件下，已经假设脱位可以比声音速度快。但是，由于与实验测量相关的挑战，此类位错的存在仍然难以捉摸。在这项工作中，分子动力学模拟用于研究基底边缘，基底螺钉，棱镜边缘和棱柱螺丝螺钉位错的位错速度。我们的结果表明，只有棱镜边缘位错才能达到超音速速度。此外，这项工作表明，理论限制速度与MG的MD结果之间的差异是由于其对脱位核周围大静水压力的敏感性，而对于Cu等FCC金属，情况并非如此。
To accurately predict the mechanical response of materials, especially at high strain rates, it is important to account for dislocation velocities in these regimes. Under these extreme conditions, it has been hypothesized that dislocations can move faster than the speed of sound. However, the presence of such dislocations remains elusive due to challenges associated with measuring these experimentally. In this work, molecular dynamics simulations were used to investigate the dislocation velocities for the basal edge, basal screw, prismatic edge, and prismatic screw dislocations in Mg in the sub-, trans-, and supersonic regimes. Our results show that only prismatic edge dislocations achieve supersonic velocities. Furthermore, this work demonstrates that the discrepancy between the theoretical limiting velocity and the MD results for Mg is due to its sensitivity to large hydrostatic stress around the dislocation core, which was not the case for fcc metals such as Cu.
