Ductile rupture of 13% Cr-4% Ni martensitic stainless steels was examined during tension testing in order to better understand the role of second phase particles in these materials. SEM fracture surface examinations revealed that micro-voids were initiated from inclusions, and these inclusions were characterized from metallographic polished sections. Effect of stress triaxiality on the growth and impingement of the micro-voids were examined using a modified model of Rice and Tracey. In the case of the cast and wrought versions, the true fracture strains predicted for the measured stress triaxiality values were in a good agreement with the measured ones. For the weld metals, only the contribution of the micro-void growth cannot explain the experimental results, and it shows that the matrix properties such as austenite content and hardness of martensite play a significant contribution. The magnitude of the final stress triaxiality ratio measured after rupture was also related to the inclusion characteristics.

中文翻译：

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13% Cr-4% Ni马氏体不锈钢的韧性断裂

在拉伸试验期间检查了 13% Cr-4% Ni 马氏体不锈钢的韧性断裂，以更好地了解第二相颗粒在这些材料中的作用。SEM 断口检测表明，微孔洞是由夹杂物引发的，这些夹杂物是从金相抛光切片中表征的。使用改进的 Rice 和 Tracey 模型检查应力三轴性对微孔洞生长和冲击的影响。在铸造和锻造版本的情况下，为测量的应力三轴度值预测的真实断裂应变与测量值非常一致。对于焊缝金属，只有微孔增长的贡献不能解释实验结果，表明奥氏体含量和马氏体硬度等基体性能起重要作用。断裂后测得的最终应力三轴度比的大小也与夹杂物特性有关。