A Constitutive Relationship of 0.1C-5Mn Steel Coupling with Transformation-Induced Plasticity Effect

Medium-manganese steel is a third-generation high-strength steel for automobiles, which has the characteristics of high strength and high plasticity. The transformation-induced plasticity (TRIP) phenomenon that occurs during the straining process can improve the work hardening ability of medium-manganese steel and delay the necking phenomenon. The microstructure of 0.1C-5Mn medium-manganese steel was observed by SEM as a two-phase structure of fine-grained ferrite and retained austenite. The law of austenite transformation and strain of medium-manganese steel under uniaxial tension is obtained through magnetic method, and the retained austenite of medium-manganese steel shows a decreasing tendency with increasing strain. The functional relationship between retained austenite and equivalent strain in medium-manganese steels is derived from a dynamic model of martensitic transformation. By using the microstructure characteristics of meso-manganese steel and mesomechanical method, a meso-manganese steel constitutive model including the TRIP effect was established, and the accuracy of the method was verified by comparing it with the curves obtained from experiments and other constitutive models. The model forms the basis to simulate the behavior of medium-manganese steels.