On the origin of dynamic strain aging in twinning-induced plasticity steels

Room temperature dynamic strain aging (DSA) is often observed from the beginning of plastic deformation in high Mn Fe 18% Mn-0.6% C and Fe-22% Mn-0.6% C twinning-induced plasticitysteels. Although the phenomenon is in many cases very pronounced, there have up to now been no attempts to explain the phenomenon of room temperature DSA in TWIP steel containing solute C. It is proposed that DSA occurs by a single diffusive jump of the C atom of the point defect complex in the stacking fault region. DSA is only observed when the C atom reorientation time is smaller than the residence time of the stacking fault at the location of the point defect complex. The latter interaction can explain the DSA-suppressing effect of Al, which increases the stacking fault energy. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.