While it is known that alloy components can segregate to grain boundaries (GBs), and that the atomic mobility in GBs greatly exceeds the atomic mobility in the lattice, little is known about the effect of GB segregation on GB diffusion. Atomistic computer simulations offer a means of gaining insights into the segregation-diffusion relationship by computing the GB diffusion coefficients of the alloy components as a function of their segregated amounts. In such simulations, thermodynamically equilibrium GB segregation is prepared by a semi-grand canonical Monte Carlo method, followed by calculation of the diffusion coefficients of all alloy components by molecular dynamics. As a demonstration, the proposed methodology is applied to a GB is the Cu-Ag system. The GB diffusivities obtained exhibit non-trivial composition dependencies that can be explained by site blocking, site competition, and the onset of GB disordering due to the premelting effect.

中文翻译：

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Cu-Ag合金中晶界偏析与晶界扩散的关系

尽管已知合金成分会偏析到晶界（GBs），并且GBs中的原子迁移率大大超过晶格中的原子迁移率，但对GB偏析对GB扩散的影响知之甚少。原子计算机模拟通过计算合金成分的GB扩散系数作为其偏析量的函数，提供了一种了解偏析-扩散关系的方法。在这种模拟中，热力学平衡GB偏析是通过半大型经典蒙特卡洛方法制备的，然后通过分子动力学计算所有合金组分的扩散系数。作为演示，将所提出的方法应用于GB-Cu-Ag系统。