Crystal plasticity finite element analysis of 3D mixed-mode notch tip fields in a textured Mg alloy

In this work, crystal plasticity finite element simulations of notched symmetric and asymmetric four-point bend specimens of a rolled AZ31 magnesium alloy having basal texture are performed. The objective is to understand the 3D nature of mixed-mode notch tip fields in this alloy and to compare the numerical results with previously reported experiments. To assess anisotropy effects, the analysis is conducted for two notch orientations, as well as for a material obeying the J 2 flow theory of plasticity, corresponding to one of the specimens. The macroscopic results agree quite well with experiments. Strong thickness variations of plastic slips, tensile twin volume fraction, and stresses are observed, which however depend on notch orientation and mode-mixity. Finally, the implications of the results for failure near the notch tip are discussed and corroborated with experimental observations.