Place: EUROMAT 2013, Sevilla, Spain
Metastable austenitic stainless steel has emerged as potential steel for automotive application. It provides high strength and high ductility at the same time because of transformation induced plasticity (TRIP) provided by the deformation induced phase transformation. Metastable austenite transforms into martensite during the straining of the material which enhances the strain hardening behaviour and also postpone the necking. Our efforts to model the deformation behaviour of this steel consist of elastoplastic deformation defined by crystal plasticity and a microscopic phase transformation model which can include transformation induced plasticity in model. The main feature of our phase transformation model is the separate treatment of strain induced and stress assisted phase transformation. Strain induced transformation causes the formation of new nuclei of martensite during plastic deformation. Model has established a direct relation between martensitic nucleation and plastic deformation. Stress assisted transformation can also happen before yield stress and depends on the driving force available for transformation. Simulation showed a significant change in the deformation behaviour of the steel by adding phase transformation as a deformation mechanism in the model.