Influence of Nb as Microalloying Element on the Recovery and Recrystallization of Fe–25Mn–12Cr–C–N Twinning-Induced Plasticity Steels

Suárez Sierra, A. and Rodríguez Baracaldo, R. and Mujica Roncery, L. and Egels, G. and Theisen, W.

Volume: Pages:
DOI: 10.1002/srin.202000417
Published: 2021

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. © 2021 Wiley-VCH GmbH

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