Initial plasticity stages in Mg alloys containing Long-Period Stacking Ordered phases using High Resolution Digital Image Correlation (HRDIC) and in-situ synchrotron radiation

Abstract

The development of strain incompatibilities between phases in an extruded MgY2Zn1(at.%) alloy during the initial stages of plastic deformation was studied using Synchrotron X-ray Diffraction experiment during in-situ tensile test and High-resolution Digital Image Correlation (HRDIC). The alloy microstructure is characterised by long LPSO fibers, crystalographically aligned non-DRXed grains with the basal plane parallel to the extrusion direction and randomly oriented fine DRXed grains. Localized transgranular shear bands form in DRXed grain areas first, just after yield. The total deformation is also accommodated by non-basal slip in the reinforcing microstructural components: non-DRXed and LPSO phases. The local deformation transmitted in these two phases is the main responsible of the appreciate ductility observed in Mg–Y–Zn alloys containing high volume fraction of LPSO phases.