Temperature dependence of the flow stress of Fe-18Mn-0.6C-xA1 twinning-induced plasticity steel

The tensile properties of Fe-18Mn-0.6C with Al-alloying additions of 0, 1.5 and 2.5 wt.% were investigated in the temperature range from 213 K (-60 degrees C) to 413 K (140 degrees C). The addition of Al resulted in an increase of the yield strength due to solid solution hardening and a decrease of the work hardening due to the suppression of deformation twinning. Both the decrease of the deformation temperature and the addition of Al suppressed the dynamic strain aging, clearly indicating an interaction between the stacking fault region of the mobile dislocation and Mn C point defect complexes. A constitutive model for the temperature dependence of the flow stress, taking into account the thermally activated dislocation glide, Al solid solution hardening and the dynamic Hall-Petch effect caused by deformation twinning, was developed. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.