Atomistic study of grain-boundary segregation and grain-boundary diffusion in Al-Mg alloys
Atomistic study of grain-boundary segregation and grain-boundary diffusion in Al-Mg alloys
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DOI：
10.1016/j.actamat.2020.10.029
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发表时间：
2020-12-01
期刊：
影响因子：
9.4
通讯作者：
Mishin, Y.
中科院分区：
文献类型：
--
作者：
Koju, R. K.;Mishin, Y.
镁晶界 (GB) 偏析和晶界扩散会影响铝镁合金的加工和性能。然而，Al 中的 Mg GB 扩散尚未通过实验测量或通过模拟预测。我们应用原子计算机模拟来预测 Mg GB 偏析的数量和自由能，以及偏析对两种合金成分的 GB 扩散的影响。在低温下，镁原子偏析成倾斜晶界，形成具有高度各向异性形状的簇。 Mg 在 Al GB 中的扩散速度比 Al 本身慢，并且与 Al GB 自扩散相比，两种成分的扩散速度都较慢。因此，镁偏析显着降低了铝镁合金中沿着晶界的质量传输速率。原子迁移率降低可以提高微观结构在高温下的稳定性。 (C) 2020 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
Mg grain boundary (GB) segregation and GB diffusion can impact the processing and properties of Al-Mg alloys. Yet, Mg GB diffusion in Al has not been measured experimentally or predicted by simulations. We apply atomistic computer simulations to predict the amount and the free energy of Mg GB segregation, and the impact of segregation on GB diffusion of both alloy components. At low temperatures, Mg atoms segregated to a tilt GB form clusters with highly anisotropic shapes. Mg diffuses in Al GBs slower than Al itself, and both components diffuse slowly in comparison with Al GB self-diffusion. Thus, Mg segregation significantly reduces the rate of mass transport along GBs in Al-Mg alloys. The reduced atomic mobility can be responsible for the improved stability of the microstructure at elevated temperatures. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.