An improved method to model dislocation self-climb
An improved method to model dislocation self-climb
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DOI：
10.1088/1361-651x/ab81a8
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发表时间：
2020-06
影响因子：
1.8
通讯作者：
Fengxian Liu;A. Cocks;S. Gill;E. Tarleton
中科院分区：
文献类型：
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作者：
Fengxian Liu;A. Cocks;S. Gill;E. Tarleton
位错可以为原子提供短路扩散路径，导致称为自爬的位错爬运动。本文提出了一种分析问题的变分原理，其中快速位错核扩散是材料再分布的主要机制。在我们以前的工作[1] Liu，Cocks和塔尔顿（2020 J. Mech. Phys. Solids 135 103783）中开发的基于线性单元的自爬升模型在这里通过采用新的有限元离散化方法显着加速。计算速度的提高使我们能够使用自攀模型作为一种有效的数值技术来模拟包括自攀和滑移的紧急位错行为。基于这种新方法，研究了不同类型刃位错偶极子破裂形成棱柱环的过程。我们证明，边缘偶极子依次夹断棱镜环，而不是自发地打破成一串的循环，迅速降低总位错能量。
Dislocations can provide short circuit diffusion paths for atoms resulting in a dislocation climb motion referred to as self-climb. A variational principle is presented for the analysis of problems in which fast dislocation core diffusion is the dominant mechanism for material redistribution. The linear element based self-climb model, developed in our previous work [1] Liu, Cocks and Tarleton (2020 J. Mech. Phys. Solids 135 103783), is significantly accelerated here, by employing a new finite element discretisation method. The speed-up in computation enables us to use the self-climb model as an effective numerical technique to simulate emergent dislocation behaviour involving both self-climb and glide. The formation of prismatic loops from the break-up of different types of edge dislocation dipoles are investigated based on this new method. We demonstrate that edge dipoles sequentially pinch-off prismatic loops, rather than spontaneously breaking-up into a string of loops, to rapidly decrease the total dislocation energy.