In situ atomistic observation of grain boundary migration subjected to defect interaction
In situ atomistic observation of grain boundary migration subjected to defect interaction
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缺陷相互作用下晶界迁移的原位原子观察
DOI：
10.1016/j.actamat.2020.08.021
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发表时间：
2020
期刊：
影响因子：
9.4
通讯作者：
Wang J. W.
中科院分区：
文献类型：
--
作者：
Zhu Q.;Zhao S. C.;Deng C.;An X. H.;Song K. X.;Mao S. X.;Wang J. W.
与晶体生长和再结晶相关的晶界迁移经常遇到晶格缺陷，而晶界与缺陷在这些动态过程中相互作用的原子机制还很不清楚。在这里，我们通过原位纳米力学测试和分子动力学模拟，系统地研究了迁移的Σ11(113)对称倾斜GBs与Au中的不同晶格缺陷(包括全位错、层错和纳米孪晶)相互作用的原子机制。实验证据表明，Σ11(113)Gb的缺陷调节机制是保守的，Gb与孪晶的耦合演化，局域原子位移主导了Gb与缺陷的相互作用。此外，剪切耦合的GB迁移不受相互作用的干扰，这是由于残留在GB上的粘性断链。这些发现对不同晶格缺陷影响下GB迁移的原子机制提供了全面的实验理解，极大地推动了GB主导塑性理论在更现实的情况下的发展。
Grain boundary (GB) migration associated with grain growth and recrystallization encounters lattice defects frequently, while the atomistic mechanisms of GB-defect interactions during these dynamic processes remain largely unclear. Here, we systematically investigate the atomistic mechanism of the interactions between migrating Σ11(113) symmetrical tilt GBs and different lattice defects, including full dislocation, stacking fault and nanotwin in Au, via the integrated in situ nanomechanical testing and molecular dynamics simulations. Experimental evidence demonstrated a conservative defect accommodation mechanism of Σ11(113) GB and a coupled GB-twin evolution, where localized atom displacement dominated the GB-defect interactions. Moreover, the shear-coupled GB migration was unperturbed by the interaction, due to the glissile residual disconnections left on the GB. These findings provide a comprehensive experimental understanding on the atomistic mechanism of GB migration under the influence of different lattice defects, which significantly advances the theoretical development of GB-dominated plasticity under more realistic circumstances.