Atomistic migration mechanisms of atomically flat, stepped, and kinked grain boundaries
Atomistic migration mechanisms of atomically flat, stepped, and kinked grain boundaries
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DOI：
10.1103/physrevb.94.165413
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发表时间：
2016-10-13
影响因子：
3.7
通讯作者：
Neugebauer, J.
中科院分区：
文献类型：
--
作者：
Hadian, R.;Grabowski, B.;Neugebauer, J.
研究了铝合金中倾斜和扭曲晶界在对称倾斜σ 7晶界附近的迁移行为< 111 >。我们发现，这些晶界分为两个主要类别的阶梯和扭结晶界周围的原子平坦的对称倾斜边界。使用这些结构与尺寸收敛的分子动力学模拟和调查快照的边界迁移过程中，我们得到一个直观的和定量的描述一般混合晶界迁移的动力学和原子机制。这种描述是密切相关的表面生长，如步骤和扭结流动机制的知名概念，并允许我们推导出分析动力学模型，解释依赖的迁移障碍的驱动力。使用这种洞察力，我们能够提取能量势垒数据的实验相关的情况下，消失的驱动力是无法从直接的分子动力学模拟和分类任意边界的基础上，他们的介观结构。
We studied the migration behavior of mixed tilt and twist grain boundaries in the vicinity of a symmetric tilt < 111 > Sigma 7 grain boundary in aluminum. We show that these grain boundaries fall into two main categories of stepped and kinked grain boundaries around the atomically flat symmetric tilt boundary. Using these structures together with size converged molecular dynamics simulations and investigating snapshots of the boundaries during migration, we obtain an intuitive and quantitative description of the kinetic and atomistic mechanisms of the migration of general mixed grain boundaries. This description is closely related to well-known concepts in surface growth such as step and kink-flow mechanisms and allows us to derive analytical kinetic models that explain the dependence of the migration barrier on the driving force. Using this insight we are able to extract energy barrier data for the experimentally relevant case of vanishing driving forces that are not accessible from direct molecular dynamics simulations and to classify arbitrary boundaries based on their mesoscopic structures.