Stresses and Micromechanical Properties of Textured Magnesium Alloy Analyzed Using Low- and High-Energy X-Ray Diffraction Methods

This study focuses on the stress characterization at the polycrystalline grain scale in textured, rolled AZ31 magnesium alloy. Grazing incidence X-ray diffraction on laboratory diffractometer, combined with an elasto-plastic self-consistent (EPSC) model, allowed the determination of macroscopic and intergranular (second-order) stress evolution during elastoplastic deformation. Furthermore, critical resolved shear stresses for activated slip systems were identified. An alternative approach to the analysis of intergranular elastic interactions and incompatibility stresses in textured materials is the transmission method using high-energy synchrotron radiation. To determine the stress evolution in extruded AZ31 alloy during uniaxial tensile tests, EPSC modeling was used to interpret the diffraction data. This analysis explained the nonlinearities of sin²ψ plots and allowed the investigation of plastic deformation mechanisms, including crystallographic slip and twinning. The key finding of this work is the identification of significant residual intergranular stresses in the plastically deformed AZ31 alloy. These stresses are strongly correlated with the orientations of the slip systems with respect to the applied stress and result from the large difference in critical resolved shear stress values, among others, between base and non-base slip systems.

This work was financed by a grant from the National Science Centre (NCN), No. UMO-2023/49/B/ST11/00774.