Quantitative tests revealing hydrogen-enhanced dislocation motion in α-iron
Quantitative tests revealing hydrogen-enhanced dislocation motion in α-iron
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DOI：
10.1038/s41563-023-01537-w
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发表时间：
2021-11
期刊：
影响因子：
41.2
通讯作者：
Long-Chao Huang;Dengke Chen;D. Xie;Suzhi Li;Yin Zhang;T. Zhu;D. Raabe;E. Ma;Ju Li;Zhihang Shan
中科院分区：
文献类型：
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作者：
Long-Chao Huang;Dengke Chen;D. Xie;Suzhi Li;Yin Zhang;T. Zhu;D. Raabe;E. Ma;Ju Li;Zhihang Shan
氢脆危害高强度钢在关键承载应用中的使用。然而，由于缺乏定量的实验证据，氢如何影响位错运动的不确定性，阻碍了我们对氢脆的理解。本文通过对α-Fe中单个螺位错的受控、周期性的弓出运动的研究，发现在2 Pa电子束激发的H_2气氛中，位错运动的起始临界应力比真空环境中低27-43%，证明了氢对螺位错运动的促进作用。此外，我们发现，除了真空脱气，循环加载和卸载有利于脱陷的氢，使位错恢复其无氢行为。这些在单个位错水平上的发现可以为氢脆模型提供信息，并指导抗氢钢的设计。
Hydrogen embrittlement jeopardizes the use of high-strength steels in critical load-bearing applications. However, uncertainty regarding how hydrogen affects dislocation motion, owing to the lack of quantitative experimental evidence, hinders our understanding of hydrogen embrittlement. Here, by studying the well-controlled, cyclic, bow-out motions of individual screw dislocations in α-iron, we find that the critical stress for initiating dislocation motion in a 2 Pa electron-beam-excited H2atmosphere is 27–43% lower than that in a vacuum environment, proving that hydrogen enhances screw dislocation motion. Moreover, we find that aside from vacuum degassing, cyclic loading and unloading facilitates the de-trapping of hydrogen, allowing the dislocation to regain its hydrogen-free behaviour. These findings at the individual dislocation level can inform hydrogen embrittlement modelling and guide the design of hydrogen-resistant steels.