Intergranular stresses evolution in magnesium studied by energy dispersive X-ray diffraction and self-consistent model - research data

Residual stresses in polycrystalline materials often originate from the anisotropy of plastic deformation. The heterogeneous activation of slip systems causes grain-level incompatibilities, which give rise to second-order stresses. Although these stresses are difficult to measure directly, they can be assessed using elastoplastic deformation models. In this study, residual stresses in deformed AZ31 magnesium alloy were investigated using energy-dispersive diffraction during in situ tensile testing at the EDDI beamline of BESSY II (HZB). The results demonstrate that microstructure-related second-order stresses are generated during plastic deformation and retained after unloading. Their distribution in Euler space correlates with the Schmid factor of non-basal slip systems, confirming their key role in intergranular stress development. Furthermore, comparison with self-consistent modelling enabled the determination of critical resolved shear stresses for the active slip systems.