Effect of grain and twin boundaries on the hardening mechanisms of twinning-induced plasticity steels

New experimental data related to the grain size and the Bauschinger effects have been obtained from a high-manganese austenitic twinning-induced plasticity steel. As the data show a strong contribution of kinematic hardening to the mechanical behaviour, a new physical-based model describing the isotropic and kinematic hardening is presented and validated in relation to the grain size and the twin spacing during straining. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.