The formation of Zn and Mg segregations at a tilt Σ5{013} <100> grain boundary (GB) in Al and the effects of these solutes on deformation behavior of polycrystalline Al were investigated using ab initio total energy calculations. Using a step-by-step modeling of the segregation process, we found that the formation of a thick segregation layer of Zn at the GB is energetically preferable, while the formation of an atomically thin segregation layer is expected in the case of Mg. To reveal the effect of segregation on the cohesive properties of Al GBs, we calculated the energy of cleavage decohesion and the shear resistance for GB sliding. We show that the segregation of Zn results in a substantial decrease in barriers for GB sliding, while the segregation of Mg increases the barriers. The results obtained allow us to explain experimental findings and demonstrate a strong relationship between chemical bonding of solute atoms, their segregation ability, and GB strength.

中文翻译：

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Zn和Mg偏析对Al：Ab从头计算模型中晶界滑动和内聚力的影响

使用从头算起的总能量计算研究了Al中倾斜Σ5{013} <100>晶界（GB）处的Zn和Mg偏析的形成以及这些溶质对多晶Al变形行为的影响。通过使用偏析过程的逐步建模，我们发现在GB上形成较厚的Zn较厚的偏析层在能量上是可取的，而在Mg的情况下则有望形成原子上较薄的偏析层。为了揭示偏析对Al GBs内聚性能的影响，我们计算了GB滑动的解离内聚能和抗剪切力。我们表明，Zn的偏析会导致GB滑动的势垒显着减少，而Mg的偏析会增加势垒。