Liu Ruiping, Wang Shaofeng, Wu Xiaozhi
Institute for Structure and Function, Chongqing University, Chongqing 400044, People's Republic of China.
J Phys Condens Matter. 2009 Aug 26;21(34):345401. doi: 10.1088/0953-8984/21/34/345401. Epub 2009 Jul 28.
The Peierls stress of the moving [Formula: see text] screw dislocation with a planar and non-dissociated core structure in Ta has been calculated. The elastic strain energy which is associated with the discrete effect of the lattice and ignored in classical Peierls-Nabarro (P-N) theory has been taken into account in calculating the Peierls stress, and it can make the Peierls stress become smaller. The Peierls stress we obtain is very close to the experimental data. As shown in the numerical calculations and atomistic simulations, the core structure of the screw dislocation undergoes significant changes under the explicit stress before the screw dislocation moves. Moreover, the mechanism of the screw dislocation is revealed by our results and the experimental data that the screw dislocation retracts its extension in three {110} planes and transforms its dissociated core structure into a planar configuration. Therefore, the core structure of the moving [Formula: see text] screw dislocation in Ta is proposed to be planar.
已计算出Ta中具有平面且非解离核心结构的移动[公式：见文本]螺旋位错的派尔斯应力。在计算派尔斯应力时，考虑了与晶格离散效应相关且在经典派尔斯 - 纳巴罗（P - N）理论中被忽略的弹性应变能，这会使派尔斯应力变小。我们得到的派尔斯应力与实验数据非常接近。如数值计算和原子模拟所示，在螺旋位错移动之前，螺旋位错的核心结构在显式应力下会发生显著变化。此外，我们的结果和实验数据揭示了螺旋位错的机制，即螺旋位错在三个{110}平面中缩回其延伸部分，并将其解离的核心结构转变为平面构型。因此，提出Ta中移动[公式：见文本]螺旋位错的核心结构为平面结构。
