Strain hardening behavior and deformation substructure of Fe-20/27Mn-4Al-0.3C non-magnetic steels

The association of strain hardening behavior with deformation substructure evolution, including dislocation substructures, mechanical twinning and microbands formation, was investigated in.Fe-20/27Mn-4A1-03C nonmagnetic steels. The critical stress for both twinning and microbanding were also estimated. With stacking fault energy enhanced to low-to-medium level, twin activation was largely diminished by reducing twin volume fraction and increasing their average spacing, such that the strain hardening rate was controlled mainly by dislocation strengthening and consequently presented a monotonous and rapid drop during entire tensile deformation process. In addition, the aggravated deformation heterogeneity in grain interior by less twin generation probably contributed to the preferential microbands formation along domain boundaries. (C) 2015 Published by Elsevier Ltd.