Predicting the Flow and Failure Properties of Dual Phase Steel Using Finite Element and Phenomenological Models

Abstract

Owing to the complexity of the mechanical response of Dual Phase (DP) steels, steel makers rely largely on experiments and trial-and-error approaches to develop new lines with higher strength and ductility in order to enable light weighting of automotive parts. Crucially, the flow and failure behaviors are intimately linked to the morphology of the microstructure. This thesis focuses on developing two approaches that use morphological features to predict the flow and failure behavior of DP Steels. In the local field approach, realistic microstructures are obtained through electron microscopy and used to construct a composite phase finite element model which is then subjected to uni-axial deformation. The second approach exploits phenomenological models to connect the deformation and failure at the microscopic level to the average mechanical response. Using basic microstructural features and flow behavior of the ferrite and martensite phases, the flow and failure behavior of DP Steels is estimated.