Effect of extrusion ratio on microstructure and mechanical properties of microwave-sintered magnesium and Mg/Y2O3 nanocomposite

The present study establishes that extrusion ratio has a critical role in enhancing microstructural and mechanical characteristics of commercially pure magnesium and a magnesium-based nanocomposite. The study reveals that the best microstructural and mechanical characteristics can be achieved in a Mg/Y2O3 nanocomposite provided it is extruded at a ratio higher than a critical extrusion ratio (19:1). An extrusion ratio at 25:1 is found to be the ratio in the present study which leads to significant enhancement in microstructural characteristics (low porosity and good distribution of particulates) and mechanical properties (microhardness, 0.2% YS and UTS) of a Mg/2 wt.%Y2O3 nanocomposite. Results of this study also show very close relationship between microhardness and strengths (0.2% YS and UTS) for both pure magnesium and Mg/Y2O3 composite extruded at different extrusion ratios.