Study of the initial plasticity stages in Mg alloys containing LPSO phases using High Resolution Digital Image Correlation (HRDIC)

Abstract

The development of strain incompatibilities between phases in an extruded MgY2Zn1(at.%) and MgY1.8Zn0.7(at.%) alloys during the initial stages of plastic deformation has been studied using High-resolution Digital Image Correlation (HRDIC) and Synchrotron Radiation Diffraction experiment during in-situ tensile test. The alloys microstructure is characterized by long LPSO fibers, crystalographically aligned non-DRXed grains with the basal plane parallel to the extrusion direction and randomly oriented fine DRXed grains. The volume fraction of the LPSO phase raises with the increase in the content of Y and Zn. Localized transgranular shear bands form in DRXed grain areas first, just after the yield stress. The total deformation is also accommodated by non-basal slip in the reinforcing microstructural components: non-DRXed and LPSO phases (Fig. 1). 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.