Optimizing the hydrogen embrittlement resistance by tuning the structures of Cu-rich nanoprecipitates in high strength martensite stainless steels
Optimizing the hydrogen embrittlement resistance by tuning the structures of Cu-rich nanoprecipitates in high strength martensite stainless steels
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DOI：
10.1016/j.actamat.2023.118722
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发表时间：
2023-01
期刊：
影响因子：
9.4
通讯作者：
Huili Sun;Wenting Lv;Yu Yang;Dongdong Li;Luchun Yan;Xiaolu Pang;Yang He;K. Gao
中科院分区：
文献类型：
--
作者：
Huili Sun;Wenting Lv;Yu Yang;Dongdong Li;Luchun Yan;Xiaolu Pang;Yang He;K. Gao
众所周知，氢气会使高强度钢脆化，严重危及材料的使用安全。富铜纳米沉淀物可能通过施加氢陷阱来减轻氢脆（HE）；同时，它们也可能有助于增强力量，从而有效地解决强度和 HE 抗性之间的权衡。然而，随着富铜沉淀物的生长，它们会经历连续的转变，这就提出了一个关键问题：到底哪一相的富铜沉淀物能产生最佳的反 HE 效应。在此，通过调整回火马氏体钢中富铜析出物的结构，我们发现钢的 HE 敏感性可显着降低高达 55.3%，同时保持钢的极限抗拉强度大致相同。此外，通过高分辨率透射电子显微镜和氢渗透测试发现，虽然所有富铜沉淀物都可以捕获氢并阻碍氢扩散，但9R结构富铜沉淀物（9R-Cu）与氢的结合最强，捕获能力最高。第一性原理计算进一步证实了这一点，该计算揭示了沉淀物/基体界面是有利的捕获位点。这些发现为通过富铜析出物补救高强度钢的 HE 敏感性提供了深刻的见解。
Hydrogen is notoriously known to embrittle high-strength steels, critically endangering the materials service safety. Cu-rich nanoprecipitates can mitigate the hydrogen embrittlement (HE) presumably by imposing hydrogen traps; in the meantime, they may also contribute to strengthening and hence effectively tackle the trade-off between strength and HE resistance. However, as the Cu-rich precipitates grow, they go through sequential transformations, raising a critical question as to exactly which phase of the Cu-rich precipitates prompts the best counter-HE effects. Here, by tuning the structures of the Cu-rich precipitates in a tempered martensitic steel, we find that the HE susceptibility of the steel can be significantly reduced by up to 55.3%, while maintaining roughly the same ultimate tensile strength of the steels. Further, by using high-resolution transmission electron microscopy and hydrogen permeation tests, it is found that, while all Cu-rich precipitates may trap hydrogen and impede hydrogen diffusion, the 9R-structured Cu-rich precipitates (9R-Cu) have the strongest binding with hydrogen and highest trapping capacity. This is further corroborated by first-principles calculations which reveal the precipitates/matrix interface as favorable trapping sites. The findings provide deep insights for remedying the HE susceptibility of high-strength steels through Cu-rich precipitates.