Hydrogen embrittlement (HE), a persistent challenge for high-strength metallic materials, imposes severe limitations on their applications in hydrogen containing environments. Recent studies have revealed that FeCoNiCrMn multi-principal element alloys (MPEAs) exhibit exceptional HE resistance, offering transformative potential for next-generation structural materials. However, the atomic-scale mechanisms governing hydrogen-defect interactions in compositionally complex alloys remain elusive due to experimental limitations in tracking H atoms. To bridge this critical knowledge gap, we developed a deep-learning interatomic potential specifically tailored for FeCoNiCrMn-H systems, which enables large-scale molecular dynamics simulations that simultaneously resolve hydrogen migration, chemical ordering, and defect evolution at atomic resolution. The simulation results reveal a multi-mechanistic synergy driven by complex interactions between deformation twinning, local chemical ordered (LCO) structures, dislocations, and grain boundaries (GBs). Specifically, it is shown that H atoms can reduce stacking fault energy and thus promote deformation twinning. Meanwhile, LCO structures dynamically trap H atoms, forming LCO-H complexes which exhibit a stronger pinning effect than the LCO structures alone. Moreover, Cr enrichment and Fe depletion at the GBs are found to increase GB fracture energy and reduce HE sensitivity. Collectively, these mechanisms contribute to the enhanced HE resistance of FeCoNiCrMn alloys. Our findings provide insights into the fundamental mechanisms underlying the exceptional HE resistance of FeCoNiCrMn alloys, and theoretical frameworks for designing MPEAs with superior mechanical properties to extend service life.

中文翻译：

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通过局部化学有序和晶界偏析增强 FeCoNiCrMn 多主元素合金的抗氢脆性

氢脆 （HE） 是高强度金属材料面临的一个持续挑战，对其在含氢环境中的应用造成了严重限制。最近的研究表明，FeCoNiCrMn 多主元素合金 （MPEA） 表现出优异的抗 HE 性能，为下一代结构材料提供了变革性的潜力。然而，由于跟踪 H 原子的实验限制，控制成分复杂合金中氢-缺陷相互作用的原子级机制仍然难以捉摸。为了弥合这一关键知识差距，我们开发了一种专门为 FeCoNiCrMn-H 系统量身定制的深度学习原子间电位，它能够实现大规模分子动力学模拟，同时在原子分辨率下解析氢迁移、化学排序和缺陷演变。仿真结果揭示了由变形孪晶、局部化学有序 （LCO） 结构、位错和晶界 （GB） 之间的复杂相互作用驱动的多机理协同作用。具体来说，研究表明 H 原子可以降低堆叠故障能量，从而促进变形孪晶。同时，LCO 结构动态捕获 H 原子，形成 LCO-H 复合物，其表现出比单独的 LCO 结构更强的固定效应。此外，发现 GB 处的 Cr 富集和 Fe 耗竭会增加 GB 断裂能量并降低 HE 敏感性。总的来说，这些机制有助于提高 FeCoNiCrMn 合金的 HE 电阻。我们的研究结果为了解 FeCoNiCrMn 合金优异的 HE 抗性的基本机制，以及设计具有优异机械性能的 MPEA 以延长使用寿命的理论框架。