Abstract 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.

中文翻译：

---

铝镁合金晶界偏析和晶界扩散的原子学研究

摘要 Mg 晶界偏析和GB 扩散会影响Al-Mg 合金的加工和性能。然而，尚未通过实验测量或通过模拟预测 Mg GB 在 Al 中的扩散。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，Mg 原子偏析成倾斜的 GB 形成具有高度各向异性形状的团簇。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，Mg 偏析显着降低了 Al-Mg 合金中沿 GB 的质量传输速率。降低的原子迁移率可能是提高微结构在高温下的稳定性的原因。