Effect of periodic image interactions on kink pair activation of screw dislocation
Effect of periodic image interactions on kink pair activation of screw dislocation
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DOI：
10.1016/j.commatsci.2023.112369
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发表时间：
2023-09
影响因子：
3.3
通讯作者：
Fei Shuang;Rigelesaiyin Ji;Liming Xiong;Wei Gao
中科院分区：
文献类型：
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作者：
Fei Shuang;Rigelesaiyin Ji;Liming Xiong;Wei Gao
沿位错线的周期边界条件通常用于计算BCC金属中螺旋位错扭对的激活势垒或形成能。虽然周期性图像相互作用对计算结果的影响是明显的，但目前还没有对这种影响进行全面的分析。在这项工作中，我们通过结合微推弹性带（NEB）模拟和基于位错力学的理论分析来量化它。NEB计算结果表明，在零应力和低应力下，激活势垒的尺寸依赖性不可忽略。理论分析提供了一种实用的方法来量化这种规模效应，而不需要耗时的NEB模拟。值得注意的是，在零应力下，得到了扭结激活势垒与位错线长度之间的简单关系，为基于NEB模拟结果计算扭结对形成能提供了一种新的方法。
Periodic boundary condition along a dislocation line is commonly used in computing activation barriers or formation energies of kink pair of screw dislocation in BCC metals. Although the effect of periodic image interactions on the computation results is obvious, there had been no comprehensive analysis on such effect. In this work, we quantify it through combined nudged elastic band (NEB) simulations and theoretical analysis based on dislocation mechanics. The NEB calculation result demonstrates a non-negligible size dependence on the activation barrier at zero and low stresses. The theoretical analysis offers a practical approach to quantify such size effect without the need of time-consuming NEB simulations. Notably, a simple relationship between kink activation barrier and dislocation line length is derived at zero stress, offering a new approach to compute kink pair formation energy based on NEB simulation results.