Effect of primary processing techniques on the microstructure and mechanical properties of nano-Y₂O₃ reinforced magnesium nanocomposites

In the present study, magnesium nanocomposites were fabricated using magnesium as matrix and nano-yttria as reinforcement. Nanocomposites with 0.2 and 0.7vol.% of Y₂O₃ particulates with 29-nm average sizes were synthesized using an innovative disintegrated melt deposition technique and blend-press-sinter powder metallurgy technique followed by hot extrusion. Microstructural characterization of the materials revealed fairly uniform distribution of reinforcement, significant grain refinement and the presence of minimal porosity in both of the nanocomposites processed using the melting and powder metallurgy techniques. Mechanical properties characterization revealed that the presence of nano-Y₂O₃ particulates led to an increase in hardness, 0.2% yield strength, UTS and ductility of pure magnesium. Amongst the composites, the ingot metallurgy processed material exhibited superior overall mechanical properties while powder metallurgy processed material exhibited excellent ductility and work of fracture. Fractography studies revealed that the typical brittle fracture of pure magnesium changed to ductile due to the incorporation of nano-Y₂O₃ particulates.