Modeling mixed microstructures using a multi-level cellular automata finite element framework

Thermo-mechanical processing (TMP) of steels are designed to yield mixed microstructures with a potential of superior mechanical properties. Prominently, creation of martensite or bainite islands in ferrite resulting in high strength dual phase steels. With the increasing demands of such steels from the automotive sector, the need to understand and predict the deformation behaviour and load requirements during the manufacture of such steels has become important.Finite elements are best suited to analyse the deformation behaviour as a function of stress, strain and temperature fields. However, representing all the facets of these mixed microstructures computationally within the finite element framework is a challenge. This is because constituents of the mixed microstructure evolve at different length scales e.g. sub-microns to microns while the finite element technique works best at the millimeter scale.The paper describes a multi-level cellular automata framework amenable to capture micro-features across the sub-micron and microns length scales. The framework is integrated with a commercially available numerical code, ABAQUS™ and tested for a plane strain compression simulation. The paper concludes with the potential of using the framework for creating designer microstructures.