Abstract Bainite formation in steels typically starts at austenite grain boundaries and continues through nucleation of bainite at newly formed bainitic ferrite/austenite interfaces. Recent experimental evidence has pointed out that austenite to bainite transformation can also proceed in the presence of martensite. Studies suggest that the presence of athermal martensite formed prior to bainite formation can accelerate the kinetics of bainite formation with the martensite/austenite interfaces acting as potential nucleation sites. In this work, a kinetic model based on the displacive mechanism of bainite formation is adapted to isolate the impact of martensite/austenite interfaces on the overall rate of bainite formation when bainite formation occurs in the presence of previously formed martensite. This adapted kinetic model is validated using dilatometer studies published in the literature on a silicon-containing low-carbon steel in which bainite formation experiments are performed both below and above the Ms temperature. The results suggest that the formalism of the existing kinetic theory can describe the effects of martensite/austenite interfaces on the bainite formation.

中文翻译：

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马氏体/奥氏体界面对M以下低合金钢贝氏体形成的影响

摘要 钢中贝氏体的形成通常从奥氏体晶界开始，并通过贝氏体在新形成的贝氏体铁素体/奥氏体界面处的形核继续。最近的实验证据表明，奥氏体到贝氏体的转变也可以在马氏体的存在下进行。研究表明，在贝氏体形成之前形成的无热马氏体的存在可以加速贝氏体形成的动力学，马氏体/奥氏体界面充当潜在的成核位点。在这项工作中，当贝氏体形成发生在先前形成的马氏体存在下时，基于贝氏体形成的位移机制的动力学模型适用于隔离马氏体/奥氏体界面对贝氏体形成总体速率的影响。使用文献中发表的关于含硅低碳钢的膨胀计研究验证了这种改编的动力学模型，其中贝氏体形成实验在低于和高于 Ms 温度的情况下进行。结果表明，现有动力学理论的形式主义可以描述马氏体/奥氏体界面对贝氏体形成的影响。