Abstract The present work investigates the crack propagation behaviour in a twinning-induced plasticity (TWIP) steel. At room temperature, the dominant fracture mechanism of TWIP steel is quasi-cleavage, which is assisted by the deformation twins since such fracture mode is circumvented at 573 K as deformation twins are prohibited. The quasi-cleavage fracture mechanism is responsible for the high notch sensitivity and low essential work of fracture (EWF) of TWIP steel at room temperature. Furthermore, the crack propagation process of TWIP steel at 298 K has been characterized quantitatively by in-situ digital image correlation (DIC) technique and J resistance curve (J-R curve). The results show that the cracking process of TWIP steel at 298 K is stable, even though cleavage patches are observed on the fracture surface. A physical model based on the dislocation behaviour at the crack tip has been proposed to explain qualitatively the mechanism responsible for the stable cleavage cracking in TWIP steels.

中文翻译：

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变形孪晶对孪生塑性钢准解理裂纹扩展的影响

摘要 目前的工作研究了孪晶诱导塑性 (TWIP) 钢中的裂纹扩展行为。在室温下，TWIP 钢的主要断裂机制是准解理，这是由变形孪晶辅助的，因为这种断裂模式在 573 K 时被避免，因为变形孪晶被禁止。准解理断裂机制是 TWIP 钢在室温下具有高缺口敏感性和低基本断裂功 (EWF) 的原因。此外，通过原位数字图像相关（DIC）技术和 J 电阻曲线（JR 曲线）定量表征了 TWIP 钢在 298 K 时的裂纹扩展过程。结果表明，TWIP 钢在 298 K 的开裂过程是稳定的，即使在断口上观察到解理斑。