Variant selection during the martensitic transformation in steels may play an important role in determining the transformation kinetics and the resulting mechanical properties. In this study, the variant selection and crystallographic features of deformation-induced martensite were investigated by quasi in situ electron backscatter diffraction (EBSD) in grade SUS321 during tensile deformation. Significant differences in variant selection between austenite (γ)→hcp-martensite (ε)→bcc-martensite (α’) and γ→α’ transformation routes were observed and reported in detail, which demonstrated that ε-martensite plays an important role in the variant selection of α’. Variant selection at different deformation stages was also analysed and revealed that α’ variants with the highest priority and variant pairs were preferred at the initial and last deformation stages in the γ→ε→α’ sequence, respectively. Meanwhile, the single α’ variant nucleated at the thin slip band keeps its crystallography feature upon further deformation in the γ→α’ sequence. In addition, the strain work of the martensitic transformation for applied loads was quantitatively estimated to explain the variant selection and associated mechanism. When these calculations are compared to the experimental results it is found that they are not able to predict which α’ variant is forming preferentially during either during the γ→α’ or the ε→α’ sequences, while only accurate predictions are obtained for the γ→ε transformation which indicates that the γ→α’ variant selection is more complex.

钢中马氏体相变过程中的变体选择可能在确定相变动力学和所产生的机械性能中起重要作用。在这项研究中，通过拉伸变形过程中SUS321级的准原位电子反向散射衍射（EBSD）研究了变形诱发马氏体的变体选择和晶体学特征。观察到并详细报道了奥氏体（γ）→hcp-马氏体（ε）→bcc-马氏体（α'）和γ→α'的转变途径在变体选择上的显着差异，这表明ε-马氏体起着重要的作用。 α'的变体选择。还分析了不同变形阶段的变体选择，发现在γ→ε→α'序列的初始和最后变形阶段，具有最高优先级的α'变体和变体对分别是优选的。同时，在细滑带上成核的单个α'变体在γ→α'序列进一步变形时保持其晶体学特征。另外，定量估计了马氏体相变对施加载荷的应变功，以解释变量选择和相关机理。将这些计算结果与实验结果进行比较后发现，它们无法预测在γ→α'或ε→α'序列中优先形成哪种α'变体，