Investigation of the micromechanical behavior of ferritic-martensitic steel under complex loading

In this paper, the mechanical behavior of dual phase steel has been investigated in the macro and micro scales as experimentally and numerically. In order to study the influence of stress states on the mechanical behavior and fracture strain of DP600, four different specimens were tested under different stress states. Afterward, the obtained microstructure images by light microscope, were utilized to generate a 3D representative volume element based on the real microstructure. The microstructure images were converted to a 3D RVE model by image processing and finite element codes in Matlab and Abaqus commercial software, respectively. Then, the ability of the micro mechanical model to predict the macro mechanical behavior was evaluated under different stress states. The results demonstrate the micro mechanical model is able to predict the macro mechanical flow curve under different stress states except for shear. Finally, the influence of stress states on the stress to strain partitioning rate and the local plastic strain at fracture point were assessed. The results show stress-strain partitioning and local plastic strain are strongly dependent on stress state.