Abstract Fracture micro-mechanisms and crack path of embrittled austenitic steel 304L by liquid sodium strained at 4.2 × 10−7 m s−1 and 573 K are investigated underneath the fracture surface by transmission electron microscopy down to the nanoscale. Automated crystal orientation and phase mapping analyses show that abundant martensitic transformation (γ austenite → α’ martensite) as well as mechanical twinning occur during the deformation of austenite and play a major role in the fracture process. A correlation between the fracture surface features and the underlying microstructural interfaces is evidenced, strengthening the conclusion that liquid metal embrittlement by sodium of austenitic steels is basically an interfacial cracking phenomenon.

中文翻译：

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液态钠中304L奥氏体钢液态金属脆化过程中裂纹路径和微观组织变化的多尺度研究

摘要 通过纳米级透射电子显微镜研究了在 4.2 × 10−7 m s−1 和 573 K 应变下液态钠对脆化奥氏体钢 304L 的断裂微观机制和裂纹路径。自动晶体取向和相映射分析表明，在奥氏体变形过程中会发生丰富的马氏体转变（γ 奥氏体 → α' 马氏体）以及机械孪晶，并在断裂过程中起主要作用。断口特征与下面的微观结构界面之间的相关性得到证明，加强了奥氏体钢钠引起的液态金属脆化基本上是一种界面开裂现象的结论。