Coincidence site lattice grain-boundaries (CSL-GBs) are commonly observed in steel alloys and play a major role in controlling their mechanical properties. In practice, CSL-GBs do experience deviations from their ideal configurations, where the deviation from the ideal symmetry plane can be modeled as sub-boundary network of misfit dislocations. In this study, segregation energy of hydrogen and carbon atoms to Σ3 (112), Σ3 (111) and Σ5 (310) CSL-GBs and their deviated configurations within Brandon's criteriorn range in alpha-iron is studied using Molecular Statics simulations. Thereafter, through utilizing Rice-Wang model the change of the cohesive GB energy is computed and correlated to misfit dislocations structures. The results show significant correlation between the crystallographic aspects of the GBs and the hydrogen/carbon embrittlement/strengthening effect. While the ideal CSL-GBs consistently show the highest resistance to hydrogen enhanced decohesion effect (HEDE), the deviations from the ideal configurations accompanied by misfit dislocation core structures along the boundaries show high solute carbon strengthening.

中文翻译：

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α-铁中近重合位点晶格晶界的溶质偏析

重合位点晶格晶界 (CSL-GBs) 通常在钢合金中观察到，并在控制其机械性能方面发挥重要作用。在实践中，CSL-GB 确实会经历与其理想配置的偏差，其中与理想对称平面的偏差可以建模为错配位错的子边界网络。在这项研究中，使用分子静力学模拟研究了氢和碳原子对 Σ3 (112)、Σ3 (111) 和 Σ5 (310) CSL-GB 的偏析能及其在布兰登标准范围内α-铁的偏离构型。此后，通过利用 Rice-Wang 模型计算内聚 GB 能量的变化并将其与错配位错结构相关联。结果表明 GB 的晶体学方面与氢/碳脆化/强化效应之间存在显着相关性。虽然理想的 CSL-GB 始终表现出对氢增强脱聚效应 (HEDE) 的最高抵抗力，但与理想配置的偏差伴随着边界上的错配位错核结构显示出高溶质碳强化。