Real microstructure based micromechanical model to simulate microstructural level deformation behavior and failure initiation in DP 590 steel

Dual phase (DP) steels having a microstructure consists of a ferrite matrix, in which particles of martensite are dispersed, have received a great deal of attention due to their useful combination of high strength, high work hardening rate and ductility. In the present work, a microstructure based micromechanical model is developed to capture the deformation behavior, plastic strain localization and plastic instability of DP 590 steel. A microstructure based approach by means of representative volume element (RVE) is employed for this purpose. Dislocation based model is implemented to predict the flow behavior of the single phases. Plastic strain localization which arises due to incompatible deformation between the hard martensite and soft ferrite phases is predicted for DP 590 steel. Different failure modes arise from plastic strain localization in DP 590 steel are investigated on the actual microstructure by finite element method.

► Strain partitioning among ferrite and martensite during straining.
► Deformation localization arises due to incompatible straining between martensite and ferrite.
► Instability occurs due to solely material inhomogeneity during straining.
► Different types of deformation localization observed in different stress state.