Deformation-induced Martensite Transformation Behavior during Tensile and Compressive Deformation in Low-alloy TRIP Steel Sheets
Hiroyuki Kawata, Takashi Yasutomi, Satoshi Shirakami, Kohki Nakamura, Eisaku Sakurada
Abstract
Transformation-induced plasticity (TRIP) is a phenomenon that improves the deformability of high-strength steel. TRIP depends on deformation-induced martensite transformation behavior. To clarify the mechanism of the transformation in low-alloy TRIP steel, we evaluated the transformation behavior via in-plane tension and compression experiments. During tensile and compressive deformation, the volume fraction of austenite (Vγ) decreased as strain and stress increased. The rate at which Vγ decreased during compressive deformation was slower than that during tensile deformation. However, after continuous deformation (i.e., tensile deformation under compression and vice versa), Vγ depended on stress, not strain. The transformation behavior was controlled by the applied stress, regardless of strain path and stored strain. It is appropriate to apply a stress-dominant strain-induced transformation model to explain this macroscopic transformation behavior.