The Effect of Zn on Microstructures and Properties of Extruded Mg-Gd-Y Alloys

Abstract

By using digital micro-hardness testing, mechanical testing, optical microscopy(OM), scanning electron microscopy(SEM), transimission electron microscopy(TEM), microstructure and mechanical properties of Mg-9Gd-3Y-xZn (x=0,1,2,3 wt.%) alloys during extrusion and following aging at 210 °C were investigated. The results showed that Zn can refined grains of the alloy. In T5 condition the average grains of the alloy without Zn addition were about 20.08 μm; the average grains of the alloys with 1 wt.% Zn addition and 3 wt.% Zn addition were about 15.26 μm and 10.17 μm, respectively. For the alloy with 1 wt.% Zn addition in peak-aged state, the values of tensile strength and yield strength reached 418MPa and 329 MPa, as well as ductility rate reached 5.6 %, respectively, exhibiting superior mechanical properties .