Abstract Hydrogen atoms absorbed by metals in hydrogen-containing environments can lead to the premature fracture of the metal components used in load-bearing conditions. Since metals used in practice are mostly polycrystalline, grain boundaries (GBs) can play an important role in hydrogen embrittlement of metals. Here we show that the reaction of GBs with lattice dislocations is a key component in hydrogen embrittlement mechanism for polycrystalline metals. We use atomistic modeling methods to investigate the mechanical response of GBs in alpha-iron with various hydrogen concentrations. Analysis indicates that dislocations impingement and emission on the GB can provoke it to locally transform into an activated state with a more disordered atomistic structure, and introduce a local stress concentration. The activation of the GB segregated with hydrogen atoms can greatly facilitate decohesion of the GB. We propose a hydrogen embrittlement model that can give better explanation of many experimental observations.

中文翻译：

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α-铁中位错与晶界反应控制的氢脆

摘要 在含氢环境中被金属吸收的氢原子会导致承重条件下使用的金属部件过早断裂。由于实际使用的金属大多是多晶的，晶界 (GB) 在金属的氢脆中起着重要作用。在这里，我们表明 GB 与晶格位错的反应是多晶金属氢脆机制的关键组成部分。我们使用原子建模方法来研究具有不同氢浓度的 α-铁中 GB 的机械响应。分析表明，GB 上的位错撞击和发射可以使其局部转变为具有更无序原子结构的激活状态，并引入局部应力集中。与氢原子隔离的 GB 的激活可以极大地促进 GB 的脱聚。我们提出了一个氢脆模型，可以更好地解释许多实验观察。