Abstract This study focused on the martensitic transformation during fatigue crack growth in twinned crystals using small compact-tension specimens to elucidate the hydrogen-induced twin boundary separation in type 304 stainless steel. In the uncharged specimen, martensite variants were formed with their habit planes parallel to the most highly shear-stressed slip plane. The crack extended in martensite that was earlier formed ahead of the crack tip and deflected from the twin boundary. Hydrogen-induced twin boundary separation occurred predominantly at the interface between martensite and austenite in a medium stress intensity range. As the stress intensity range increased, martensite variants symmetrically arranged with respect to the twin plane dominated, suggesting that a slip-off crack growth mechanism was facilitated by hydrogen.

中文翻译：

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循环载荷作用下304不锈钢氢致孪晶界分离的晶体学研究

摘要 本研究重点研究了孪晶晶体疲劳裂纹扩展过程中的马氏体转变，使用小型致密拉伸试样阐明了 304 型不锈钢中氢致孪晶边界分离。在不带电的试样中，形成马氏体变体，其习性平面平行于最高剪切应力的滑动平面。裂纹在早先在裂纹尖端之前形成并从孪晶边界偏转的马氏体中延伸。氢致孪晶边界分离主要发生在中等应力强度范围内的马氏体和奥氏体之间的界面处。随着应力强度范围的增加，关于双晶面对称排列的马氏体变体占主导地位，这表明氢促进了滑动裂纹扩展机制。