Double-hit compression behavior of TWIP steels

The study of hot deformation characteristics of high-Mn twinning induced plasticity (TWIP) steels is of great importance due to their superior mechanical properties and potential applications for structural applications. In the present work, the static restoration behavior of 29 wt% Mn TWIP steel has been investigated using the double-hit compression testing technique. The tests were performed at 950–1150 °C under constant strain rate (0.1 s−1). The results indicated a hardening behavior when the second pass deformation was applied after the interpass time. To justify the strengthening behavior different mechanisms were considered. The static strain aging phenomenon, involving interactions between interstitial atoms (carbon atoms) and dislocations were believed to be the main reasons of interpass hardening in this study. The retardation of restoration processes due to the formation of high frequency annealing twins during interpass time as planar obstacles to the dislocation glide were believed as other reasons to explain this phenomenon.

► The static restoration behavior of a new grade of austenitic TWIP steels has been investigated.
► An interpass time strengthening phenomenon was observed.
► The result was discussed based on the static strain aging phenomenon and the formation of high frequency annealing twins during interpass time.