Deformation-induced Martensite Transformation Behavior during Tensile and Compressive Deformation in Low-alloy TRIP Steel Sheets

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 (V-gamma) decreased as strain and stress increased. The rate at which V-gamma decreased during compressive deformation was slower than that during tensile deformation. However, after continuous deformation (i.e., tensile deformation under compression and vice versa), V-gamma 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.