Strain partitioning in a dual-phase steel under plane strain compression

Modern design of steels with improved mechanical properties is often based on multiphase microstructures such as in dual-phase steels. The tailoring of these alloys requires a thorough understanding of strain partitioning and the correlation of strain related phenomena in different scales and under different loading paths. These questions are usually addressed by means of empirical techniques and numerical simulations using representative volume elements (RVE). The assessed loading conditions are most often simple shear, uniaxial tension, and hole expansion and these studies mainly focus on microstructural damage progression under low strains. This study aims to develop a coupled experimental-numerical approach to examine the fractal nature of strain partitioning in a dual-phase steel (DP600) under plane strain compression. This deformation path allows the achievement of significantly higher strains up to the extension of possibly promoting grain fragmentation within highly deformed shear bands. From a fractal perspective, it is demonstrated the development of micro-scaled shear bands due to microstructural heterogeneities within macro-shear bands characteristic of plane strain compression. Additionally, the results obtained from the 2D-RVE model were critically examined and compared with several experiments at different scales to provide further understanding on the limitations and capabilities of the approach.