Kinetics of strain-induced phase transformation in TRIP steel

Abstract

This paper discusses the kinetics of the fronts of localized plastic deformation in TRIP steel using a combination of DIC methods and magnetization measurements. It is shown that the kinetics of deformation fronts, which is mainly determined by the stages of the hardening curve, is consistent with changes in the phase composition. A phase transformation starts with the propagation of Lüders bands and then proceeds through the formation and propagation of Portevin–Le Chatelier bands, but only in the region of increasing strain hardening coefficient. After the transition to the stage where the hardening coefficient decreases, the γ → αʹ phase transformation decays and is no longer the predominant mechanism of jerky flow. Both types of plastic instability in TRIP steel can be described using the autowave concept of localized plasticity.