Strain rate behavior investigations of aluminium and AA 2024 using crystal plasticity

Abstract

The work presented in this thesis is focused on crystal plasticity-based modeling of the deformation behavior of aluminium and its alloy AA2024 over a wide range of strain rates. Years of research have been published on the numerical modeling of strain rate-based deformation of AA2024 alloy, and new developments in computing have made it possible for researchers to improve their modeling approaches. The majority of the numerical investigations on the prediction of deformation behavior of AA2024 alloy rely on the use of empirical macroscopic constitutive models, which fail to take into account the actual microscopic-level mechanisms (i.e. crystallographic slip) causing plastic deformation. In order to achieve accurate predictions, the microstructure-based constitutive models involving the underlying physical deformation mechanisms are more reliable. In particular, crystal plasticity (CP) is widely regarded as a very competent framework for investigating the impacts of microstructure on plastic deformation in metals. Therefore, the use of CP models can more accurately predict the behavior of crystalline materials. The present research employs the crystal plasticity modeling approach for predicting the deformation behavior of aluminium and its alloy AA2024. Initially, a phenomenological CP model implemented in DAMASK is used to predict the stress-strain behavior of aluminium and aluminium alloy AA2024-T3 at different strain rates. For aluminium, a single crystal of two different orientations named S1 and S2 is used to perform the simulations. For AA2024-T3 alloy, a polycrystalline representative volume element (RVE) is used for performing simulations at different strain rates. The material parameters are determined by fitting the experimental curves and the simulated curves are compared with the experimental results from the literature. newline