ABSTRACT We examined the hydrogen embrittlement mechanism in SUS304 stainless steel by conducting synchrotron radiation diffraction experiments and high-resolution TEM observations. It was found that the strength of SUS304 was lowered by adding hydrogen and that brittle fracture occurred with elongation of approximately 20%. Synchrotron radiation diffraction experiments revealed that the formation of the ε phase having a hexagonal close-packed structure was promoted by hydrogen addition to SUS304. In addition, high-resolution TEM observations revealed the presence of the ε phase with a width of up to approximately 5 nm at the twin boundary in the twin structure due to the γ phase. Furthermore, a large number of stacking faults were formed in the ε phase. These results imply that the strain-induced martensitic phase transformation from the γ phase to the α′ one was suppressed by hydrogen addition to SUS304 and that the ε phase having a large number of stacking faults was stabilised as an intermediate phase during the α′ martensitic phase transformation. The formation of the ε phase having a large number of stacking faults should presumably originate in hydrogen embrittlement.

中文翻译：

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SUS304不锈钢应变诱导ε-马氏体相变与氢脆

摘要 我们通过同步辐射衍射实验和高分辨率 TEM 观察研究了 SUS304 不锈钢的氢脆机制。发现SUS304的强度因添加氢而降低，并且在伸长约20％时发生脆性断裂。同步辐射衍射实验表明，在SUS304 中加入氢促进了具有六方密堆积结构的ε 相的形成。此外，高分辨率 TEM 观察表明，由于 γ 相，在孪晶结构的孪晶边界处存在宽度高达约 5 nm 的 ε 相。此外，在ε相中形成了大量的堆垛层错。这些结果表明，从 γ 相到 α' 相的应变诱导马氏体相变通过向 SUS304 中添加氢而受到抑制，并且具有大量堆垛层错的 ε 相在 α' 马氏体相变过程中作为中间相被稳定化。相变。具有大量堆垛层错的 ε 相的形成可能源于氢脆。