Abstract Investigating the partitioning effect of substitutional and interstitial elements on the migration of transformation interfaces during austenite-ferrite phase transformation in steels with the conventional experimental method is extremely challenging due to interaction between the solute atoms and the transformation interfaces. Additionally, the simultaneous nucleation of new phases during phase transformations limits the accuracy of extracted growth rates from experimental kinetics measurements of phase fractions. In a novel experimental approach, the cyclic partial phase transformation concept is used to avoid the effect of nucleation on total kinetics of phase transformations. In this study, a Fe-0.5Mn alloy in the presence and absence of interstitial C and N additions is subjected to different cyclic transformation routes to examine the possible interaction between solute atoms and migrating interfaces. The experimental results are in semi-quantitative agreement with modelling predictions made by the local equilibrium approach and provide indirect evidence of Mn partitioning at austenite/ferrite interface in absence of any interstitial elements. It is also confirmed that the presence of interstitial elements promotes Mn interaction with the interface, whereas N promotes more Mn partitioning at transformation interface compared to C.

中文翻译：

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C和N及其缺失对Fe-0.5Mn合金中奥氏体-铁素体相变动力学的影响

摘要 由于溶质原子和相变界面之间的相互作用，用传统的实验方法研究置换元素和填隙元素对钢中奥氏体-铁素体相变过程中相变界面迁移的分配作用极具挑战性。此外，相变过程中新相的同时成核限制了从相分数的实验动力学测量中提取的生长速率的准确性。在一种新的实验方法中，循环部分相变概念用于避免成核对相变总动力学的影响。在本研究中，Fe-0. 在存在和不存在间隙 C 和 N 添加物的情况下，5Mn 合金经受不同的循环转变路线，以检查溶质原子和迁移界面之间可能的相互作用。实验结果与局部平衡方法做出的建模预测在半定量上一致，并提供了在没有任何间隙元素的情况下在奥氏体/铁素体界面上锰分配的间接证据。还证实间隙元素的存在促进了 Mn 与界面的相互作用，而与 C 相比，N 促进了转变界面处更多的 Mn 分配。实验结果与局部平衡方法做出的建模预测在半定量上一致，并提供了在没有任何间隙元素的情况下在奥氏体/铁素体界面上锰分配的间接证据。还证实间隙元素的存在促进了 Mn 与界面的相互作用，而与 C 相比，N 促进了转变界面处更多的 Mn 分配。实验结果与局部平衡方法做出的建模预测在半定量上一致，并提供了在没有任何间隙元素的情况下在奥氏体/铁素体界面上锰分配的间接证据。还证实间隙元素的存在促进了 Mn 与界面的相互作用，而与 C 相比，N 促进了转变界面处更多的 Mn 分配。