Abstract Molecular dynamics simulations of transient stress drops have been carried out in different regimes on a nanocrystalline Aluminum sample with average grain size of 12 nm. Besides confirming the interpretation of experimental results obtained during in situ X-ray diffraction, the creep simulations performed at 2 or 3 orders of magnitude lower strain rates than usual reveal deformation mechanisms that have not been observed previously. First of all, it is evidenced that the misfit dislocations available at the GB assist the propagation of a lattice dislocation on a plane with low resolved shear stress. Furthermore, it is shown that the interaction of two dislocations gliding on parallel slip planes can result in the emission of a vacancy in the grain interior. Finally, the importance of the Schmid factor in the activation of slip in nanocrystalline structures is discussed.

中文翻译：

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纳米晶铝原子模拟中降低应变率下的位错相互作用

摘要 对平均晶粒尺寸为 12 nm 的纳米晶铝样品在不同状态下进行了瞬态应力降的分子动力学模拟。除了确认在原位 X 射线衍射期间获得的实验结果的解释外，在比通常低 2 或 3 个数量级的应变率下进行的蠕变模拟揭示了以前未观察到的变形机制。首先，有证据表明 GB 处可用的错配位错有助于晶格位错在具有低分辨剪切应力的平面上传播。此外，研究表明，在平行滑移面上滑动的两个位错的相互作用会导致晶粒内部空位的发射。最后，