Correlation between stacking fault energy and deformation microstructure in high-interstitial-alloyed austenitic steels

Abstract

The correlation between stacking fault energy (SFE) and deformation microstructure of high-interstitial-alloyed austemtic Fe-18Cr-10Mn-(N or N + C) alloys was investigated As the content of the interstitial elements increased, the deformation microstructure changed in a sequence strain-induced martensitic transformation, mixture of martensite and twin, and finally deformation twin The SFE, playing an important role in the transition of deformation microstructure, was evaluated by the Rietveld whole-profile fitting combined with the double-Voun size strain analysis for newton diffraction profiles of tensile-strained bulk samples At fixed N + C content, the ratio of mean-squared strain to stacking fault probability remained constant regardless of the accumulated strain, whereas the ratio gradually increased with increasing N + C content Almost linear dependence of measured SFE on N + C content could be established According to the SFE, deformation bands exhibited distinct substructures, and their particular intersecting behavior resulted in the formation of different types of products (secondary epsilon martensite, alpha' martensite and secondary twin) at the intersecting regions (C) 2010 Acta Materialia Inc Published by Elsevier Ltd All rights reserved