On the Relationship between Mechanical Properties and Mechanisms of Plastic Deformation in Metastable Austenitic Steels

Abstract

The requirements of the automotive industry for materials exhibiting increased structural performances are continuously increasing. These materials must remain ductile during the forming operations while also exhibiting improved strength and energy absorption capacities.New highly alloyed steel grades have been studied for a few years now, due to their exceptional mechanical properties resulting from interactions between dislocation plasticity, transformation plasticity and mechanical twinning.This study deals with the mechanical properties of steel grades presenting high manganese compositions. At room temperature, several phase transformations (γ→α', γ→ɛ and ɛ→α′) were found to occur when the samples are deformed. The effect of different annealing conditions on the mechanical properties and the transformation sequence is analysed. The evolution of the work‐hardening of the samples is interpreted in connection with the kinetics of the phase transformations.