Influence of Volume Fraction and Distribution of Martensite Phase on the Strain Localization in Dual Phase Steels

Abstract

The present work investigates by finite element (FE) analysis the effects of volume fraction and distribution of martensite phase on the strain localization in three commercial dual-phase (DP) steels. Strain localization is considered here as a precursor to fracture. The microstructures of the investigated steels were explicitly represented in the FE model using the representative volume element (RVE) approach. The properties of the ferrite and the martensite were determined from tensile test data for the investigated steels using an inverse identification procedure. The strain field in each phase was determined and related to the distribution of the martensite in the soft ferrite phase. Strain localization in the hard martensite phase was discussed with respect to fracture initiation and propagation in the investigated DP steels. The numerical results are coherent with microstructural observations of fracture initiation in DP steels.