The influence of Nb on the microstructure during annealing at 950, 1000, and 1100 °C is analyzed in two types of twinning‐induced plasticity (TWIP) steels, Fe–25Mn–12Cr–C–N (TWIP‐0) and Fe–25Mn–12Cr–C–N–Nb (TWIP‐Nb). The addition of Nb as a microalloying element affects various phenomena taking place during annealing, namely, recrystallization, grain coarsening, and recovery processes. Microstructural characterization is conducted via light microscopy, scanning electron microscopy, and electron back scattering diffraction (EBSD). Recovery takes place after annealing at 950 °C, where remaining deformation and grain nucleation can be seen. Microstructural analyses indicate that the location of the recrystallization nuclei in the recovered structure is associated with the local chemical segregation of Mn and Cr, which leads to differences in the driving force for the martensitic transformation at microscale, and therefore local deformation mechanisms. The presence of Nb as a microalloying element decelerates recovery and recrystallization kinetics. At 1100 °C/10 min, both steels exhibit complete recrystallization; moreover, abnormal grain growth starts.

中文翻译：

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铌作为微合金元素对孪晶诱导可塑性钢Fe-25Mn-12Cr-C-N的恢复和再结晶的影响

在两种孪生感应塑性（TWIP）钢中，分析了Nb对950、1000和1100°C退火过程中显微组织的影响：Fe–25Mn–12Cr–C–N（TWIP-0）和Fe– 25Mn–12Cr–C–N–Nb（TWIP–Nb）。Nb作为微合金元素的添加会影响退火过程中发生的各种现象，即重结晶，晶粒粗化和恢复过程。通过光学显微镜，扫描电子显微镜和电子反向散射衍射（EBSD）进行微观结构表征。在950°C退火后恢复，可见残余变形和晶粒成核。显微组织分析表明，重结晶核在回收结构中的位置与Mn和Cr的局部化学偏析有关，这导致在微观尺度上马氏体相变的驱动力不同，从而导致局部变形机制。Nb作为微合金元素的存在会降低回收率和重结晶动力学。在1100°C / 10 min时，两种钢均显示出完全的重结晶。而且，开始异常的晶粒长大。