Development and property evaluation of aluminum alloy reinforced with nano-ZrO2 metal matrix composites (NMMCs)

In the present research, nano-ZrO2 particulates were dispersed in aluminum alloy (LM 13) by melt deposition technique followed by hot extrusion. The size of the particles dispersed varies from 50 to 80 nm and amount of addition varies from 3 to 15 wt.% in steps of 3%. Microstructural studies of the nano-composite developed indicate that there is uniform distribution of the reinforcement in the matrix alloy with significant grain refinement and retention of residual porosity. Mechanical properties reveal that the presence of nano-ZrO2 particulates has improved significantly the strength and hardness with slight reduction in ductility as compared against the matrix alloy. Fractography of the specimens showed that the fracture behavior of matrix alloy has changed from ductile intergranular mode to cleavage mode of fracture. Results of the thermal and electrical tests on the composite developed indicate that, thermal conductivity and electrical resistance both decreased with increase in reinforcement content.