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

Crystal plasticity finite element simulations are frequently employed to predict the plastic anisotropy of polycrystalline metals based on their crystallographic texture. However, precipitation in age-hardenable aluminium alloys is known to affect the texture-induced plastic anisotropy. A new modelling approach that incorporates this effect into crystal plasticity constitutive models is presented to address this issue. The approach is based on the hypothesis that precipitation occurs in a global preferred direction, resulting in direction-dependent hardening behaviour for the slip systems. The direction dependency is implemented into a conventional crystal plasticity constitutive model by modification of the hardening law using only one additional parameter. To demonstrate the applicability of the new modelling approach, it is applied to an AA6014-T4 age-hardenable aluminium alloy and compared against the current state-of-the-art crystal plasticity modelling approach, taking only the crystallographic texture into account. The results demonstrate that the predicted accuracy of the plastic anisotropy for the AA6014-T4 aluminium alloy studied is significantly improved by the proposed new modelling approach for incorporating precipitation-related effects.