Effect of length scale of Al2O3 particulates on microstructural and tensile properties of elemental Mg

In the present study, magnesium-based composites were fabricated with three different sizes (ranging from nano- to micro-meter scale) of 1.1 vol.% Al2O3 particulate reinforcement using blend-press-sinter methodology avoiding ball milling. Microstructural characterization of the materials revealed reasonably uniform distribution of Al2O3 reinforcement, significant grain refinement and the presence of minimal porosity. Mechanical property characterization revealed that the incorporation of Al2O3 particulates as reinforcement led to a simultaneous increase in hardness, 0.2% yield strength, UTS and ductility of pure magnesium. The results further revealed that the 0.2% yield strength, UTS and ductility combination of the magnesium containing nano-size and submicron size Al2O3 remained higher when compared to high strength magnesium alloy AZ91 reinforced with much higher amount of micron size SiC particulates. An attempt is made in the present study to correlate the effect of different length scales of Al2O3 particulates on the microstructural and mechanical properties of magnesium.