Microstructure and mechanical properties of a Mg-Zn-Y alloy produced by a powder metallurgy route

In this paper, a bulk Mg-Zn-Y alloy reinforced by quasicrystalline particles was produced by hot extrusion of rapidly-solidified powders. MgZn4.3Y0.7 powders with different particle sizes were prepared by an inert gas atomizer and then extruded at 380 degrees C with extrusion ratios of 10:1, 15:1, and 20:1. Microstructural studies were performed using an optical microscope, scanning electron microscope, transmission electron microscope, and X-ray diffraction. The mechanical strength and hardness of the extruded materials were enhanced by employing finer Mg alloy powders. More uniform deformation of powders in extruded billets with good tensile properties was achieved at higher extrusion ratios, especially for finer powders. The high strength of the MgZn4.3Y0.7 alloy was preserved at elevated temperatures due to the presence of icosahedral phase nanoparticles. (C) 2012 Elsevier B.V. All rights reserved.