Incorporating precipitation-related effects on plastic anisotropy of age-hardenable aluminium alloys into crystal plasticity constitutive models

Abstract

Crystal plasticity finite element simulations are frequently employed to predict the plastic anisotropy of polycrystalline metals based on their crystallographic texture. In age-hardenable aluminium alloys, however, the texture-induced plastic anisotropy is known to affect by precipitation. This paper presents a new modelling approach to incorporate this effect into crystal plasticity constitutive models. The approach focuses on the overall effect of precipitation, which is assumed to result in an additional directional dependency with respect to a global material orientation, superimposed with the texture-induced plastic anisotropy. This additional directional dependency is implemented into a conventional crystal plasticity constitutive model via a modified hardening law that introduces two new parameters, of which only one is treated as a free parameter. To demonstrate the applicability of the new modelling approach, it is applied to an age-hardenable AA6014-T4 aluminium alloy and compared against a state-of-the-art crystal plasticity constitutive model that considers only crystallographic texture. The results demonstrate that the new modelling approach significantly improves the prediction accuracy of the plastic anisotropy for the AA6014-T4 aluminium alloy studied.