Motion of a screw dislocation in a two-dimensional Peierls potential
Motion of a screw dislocation in a two-dimensional Peierls potential
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DOI：
10.1103/physrevb.55.6180
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发表时间：
1997-03-01
影响因子：
3.7
通讯作者：
Takeuchi, S
中科院分区：
文献类型：
--
作者：
Edagawa, K;Suzuki, T;Takeuchi, S
螺旋位错在晶格中的运动是通过二维Peierls势中的扭折对的形成而发生的。采用位错线张力模型，计算了三维空间中非平面扭折对的鞍点组态和相应的激活能。该方法被应用于bcc晶格中的[111]螺位错，假设在（111）平面中具有三重周期正弦Peierls势。在这种势中，位错可以使扭结对从一个稳定的直线构型向三个相邻构型中的任何一个成核。取决于所施加的应力的方向，三个激活过程的相对频率确定临界流动应力的温度依赖性和总滑移的方向。计算结果很好地再现了体心立方过渡金属的塑性各向异性。
Motion of a screw dislocation in a crystal lattice occurs by kink pair formation in a two-dimensional Peierls potential. Employing the line-tension model of a dislocation, the saddle-point configuration of a nonplanar kink pair in three-dimensional space and the associated activation energy an calculated. The method is applied to a [111] screw dislocation in a bcc lattice assuming a threefold periodic sinusoidal Peierls potential in the (111) plane. In this potential the dislocation can nucleate a kink pair from one stable straight configuration towards any of the three adjacent ones. Depending on the direction of the applied stress the relative frequencies of the three activation processes determine the temperature dependence of the critical flow stress and the direction of total slip. The calculations reproduce well the plastic anisotropy of bcc transition metals.