Analysis of the Microstructure Role in the Yield Asymmetry of Extruded Mg-LPSO Alloys Using In Situ Diffraction Experiments

The effect of microstructure and processing parameters on the mechanical behavior of extruded Mg-Y$_{2x}$-Zn$_x$ alloys containing different volume fractions of the long-period stacking order (LPSO) phase is evaluated using in situ diffraction experiments. The Mg-LPSO extruded alloys exhibit a microstructure consisting of a mixture of fine dynamically recrystallized $α$-Mg grains, highly oriented non-recrystallized coarse $α$-Mg grains with the basal plane parallel to the extrusion direction, and particles of the LPSO phase elongated in the extrusion direction. The volume fraction of dynamically recrystallized $α$-Mg grain areas tends to increase as the volume fraction of the LPSO phase and the processing stress increase. In situ diffraction experiments have allowed the understanding of the elastic–plastic behavior of non-DRXed and DRXed grains, and their individual contribution to the macroscopic deformation of magnesium alloys containing LPSO phases and, consequently, the reverse tension–compression asymmetry