The transformation of edge dislocation dipoles in aluminium
The transformation of edge dislocation dipoles in aluminium
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DOI：
10.1016/j.actamat.2008.05.019
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发表时间：
2008-10
期刊：
影响因子：
9.4
通讯作者：
H. Wang;Dongsheng Xu;Ren-fu Yang;P. Veyssiére
中科院分区：
文献类型：
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作者：
H. Wang;Dongsheng Xu;Ren-fu Yang;P. Veyssiére
利用分子动力学研究了铝中解离边位错偶极子的转变，偶极子高度范围为1到10{111}面间距，温度高达900K。考虑了空心、垂直紧致和倾斜偶极子三种构型，并比较了它们的相对稳定性。空心在有限温度下是不稳定的。偶极子既不会湮灭也不会形成稳定的空心核，而是转变为高度和温度相关的布局，包括包含有序自由体积的核，锯齿状断裂偶极子和聚集的截断层错四面体（SFT）。在最高温度下形成小的单个SFT，证明了短距离管道扩散。这些重新排列的结构是移动位错的强大障碍，因此是位错纠缠和单滑移自图案化的潜在核位。本文报道了一种由局域偶极钳断引起的空位团簇直接形成SFT的热激活机制。
The transformations of dipoles of dissociated edge dislocations in aluminium are investigated using molecular dynamics for dipole heights ranging from one to ten {111} interplanar distances and at temperatures up to 900K. Three types of configurations, hollow, vertical compact and inclined dipoles, are considered and their relative stabilities compared. Hollows are unstable at finite temperature. Dipoles neither annihilate nor form stable hollow cores but transform into height- and temperature-dependent layouts including cores containing ordered free volumes, zigzag faulted dipoles and agglomerated truncated stacking fault tetrahedra (SFT). Small individual SFT are formed at the highest temperatures, attesting to short-range pipe diffusion. These rearranged configurations are strong obstacles to mobile dislocations, thence potential nucleation sites for dislocation entanglement and self-patterning under single slip. A new thermally activated mechanism of SFT formation directly from vacancy clusters resulting from local dipole pinching-off is reported.