A NEW QUASI-CRYSTALLINE PHASE IN MG-ZN-Y-ZR CAST INGOT

An icosahedral quasicrystalline phase in as-cast Mg-5.78 wt% Zn-0.89 w t% Y-0.48 wt% Zr alloy has been identified by using scanning transmiss ion electron microscopy (STEM). The selected area diffraction patterns (SADPs) from the phase show a five-fold symmetry of a quasicrystallin e structure. The energy dispersive X-ray spectra (EDS) for the phase i ndicate that the quaternary phase has a chemical composition 67.5 at% Zn, 19.4 at% Mg, 8.1 at% Y and 4.9 at% Zr.