Effect of Zn and Al alloying on slip system activation and strengthening mechanisms in magnesium alloys

The deformation mechanisms of Zn- and Al-alloyed Mg were investigated using in-situ three-dimensional synchrotron X-ray diffraction (3DXRD). The activation of basal and prismatic slip was quantified in Mg-1Al (A1), Mg-1 Zn (Z1), and Mg-1Al-1 Zn (ZA11) alloys in order to assess the influence of solute alloying on slip system competition. The results reveal that the combined addition of Zn and Al facilitates prismatic slip activation by reducing its critical resolved shear stress (CRSS), and leads to the lowest RSS$_{prism}$/RSS$_{basal}$ ratio of 5.44, compared to 6.25 in A1 and 6.23 in Z1. This indicates a more balanced activation of basal and non-basal slip systems. Grain rotation analysis further suggests that ZA11 accommodates deformation more effectively through non-basal slip, reducing stress localization. These findings provide direct insights into how solute interactions influence slip system activity and offer guidelines for optimizing Mg alloys for improved ductility and mechanical performance.