Abstract We employ atomistic computer simulations to study the structure and migration behavior of a Σ11 symmetrical tilt grain boundary in a 4-component model FCC high-entropy alloy (HEA) (CuNiCoFe). The results are compared to grain boundaries in elemental metals and a so-called ‘average-atom’ sample. We find that the repeating structural units characterizing the static grain boundary structure show the same repeating structural units for all samples, while the high temperature equilibrium grain boundary structure is most strongly influenced by presence of stacking faults. Under an applied synthetic driving force, this GB migrates by a mechanism assisted by partial dislocations in all materials. For this reason the grain boundary mobilities and stacking fault energies are directly related. Moreover, the HEA sample and the average-atom sample show almost identical mobilities suggesting that local chemical fluctuations play a minor role. Solute segregation to the GB in the HEA suppresses GB migration up to very high temperatures and might be the main cause for reduced grain growth in FCC HEAs.

中文翻译：

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高熵合金的晶界结构和迁移率：面心立方 CuNiCoFe Σ11 对称倾斜晶界的比较分子动力学研究

摘要 我们采用原子计算机模拟来研究 4 组分模型 FCC 高熵合金 (HEA) (CuNiCoFe) 中 Σ11 对称倾斜晶界的结构和迁移行为。结果与元素金属中的晶界和所谓的“平均原子”样品进行了比较。我们发现表征静态晶界结构的重复结构单元对所有样品显示相同的重复结构单元，而高温平衡晶界结构受堆垛层错的影响最大。在施加的合成驱动力下，该 GB 通过所有材料中部分位错辅助的机制迁移。由于这个原因，晶界迁移率和堆垛层错能直接相关。而且，HEA 样品和平均原子样品显示出几乎相同的迁移率，表明局部化学波动起次要作用。HEA 中向 GB 的溶质偏析抑制 GB 迁移到非常高的温度，并且可能是 FCC HEA 中晶粒生长减少的主要原因。