FEM modeling of the flow curves and failure modes of dual phase steels with different martensite volume fractions using actual microstructure as the representative volume

The flow curves and failure modes of dual phase steels containing 18 and 44 vol.% martensite were predicted using a micromechanical-based finite element method. Actual microstructures of the dual phase steels obtained by scanning electron microscope (SEM) were used as the representative volume elements (RVEs) in the calculations. Ductile failure of the representative volume was predicted as plastic strain localization during deformation. Computations were conducted on the representative volume to quantitatively evaluate the effects of mechanical properties of the dual phase constituents and their volume fractions on the macroscopic mechanical properties of the dual phase steels. The computational results were compared with the experimentally obtained data. It was found that the computational method can predict well both strength and ductility of the studied dual phase steels. Moreover, based on the computational results, shear dominant failure mode occurs in both of the studied dual phase steels which correlate with experimental findings.