Crystal plasticity modeling of the effect of precipitate states on the work hardening and plastic anisotropy in an Al-Mg-Si alloy

In this study the influence of precipitates on the mechanical properties and plastic anisotropy of an age hardenable aluminum alloy during uniaxial loading was investigated using crystal plasticity modeling. The kinetics model of Myhr et al. was used to obtain the solute and precipitate features after different cycles of aging treatment. The amounts of solute, precipitate size and volume fraction, and dislocation density varying during deformation, were used to calculate the slip system strength. An explicit term was obtained based on the elastic inclusion model for the directional dependency of internal stress developed by non-shearable rod shape precipitates. Also, a dislocation evolution model was modified to assess the anisotropic influence of non-shearable precipitate on work hardening, and the effects of solute content on the rate of dynamic recovery. It was found that the model results were in good agreement with experimental uniaxial flow stress obtained under different aging conditions. The application of the model to single crystal revealed that the precipitates can reduce crystallography anisotropy, which in part was attributed to the precipitate induced anisotropy.