oa Improving mechanical and thermal properties of AZ31 magnesium alloy through simultaneous addition of aluminum and nano-alumina

In the present study, AZ51 magnesium alloy and AZ51-Al2O3 magnesium nano-composite was successfully synthesized incorporating elemental aluminium (Al) (2 wt.%) and simultaneous addition of Al (2 wt.%) and nano-sized Al2O3 (1.5 vol.%) into pure AZ31 alloy, respectively, using an innovative disintegrated melt deposition technique followed by hot extrusion. Microstructural characterization studies revealed uniaxial grain size, reasonably uniform distribution of particulates/intermetallics in the matrix and minimal porosity. Thermal properties characterization revealed that addition of both Al and nano-sized Al2O3 reduced the coefficient of thermal expansion (CTE) of monolithic AZ31. The presence of both Al2O3 nanoparticulates and aluminum also assisted in improving overall mechanical properties of AZ31 magnesium alloy. Microhardness can be increased by about 67% with the addition of Al and Al2O3 into pure AZ31 when compared to pure AZ31 alloy. Newly developed AZ51-Al2O3 nano-composite also exhibited higher modulus of elasticity (80%), 0.2% yield strength (17%), ultimate tensile strength (14%), ductility (26%) and work of fracture (46%) when compared to a monolithic AZ31 alloy. The results suggest that both the new alloy and composite have significant potential in diverse engineering applications when compared to the AZ31 alloy and can be used by weight critical aerospace and automotive industries to save energy.