Effect of microwave sintering on the mechanical characteristics of Al/kaoline/SiC hybrid composite fabricated through powder metallurgy techniques

Abstract

In this present study, Aluminium hybrid metal matrix composite reinforced with Kaoline and SiC particles was synthesized through the powder metallurgy technique. Tensile, hardness, compression and porosity tests were performed on the Al+ 6% Kaoline+ 6% SiC composite to explore the effects of microwave sintering on the mechanical behaviour of the fabricated composite. Results reveal an enhancement of 23.02%, 22.29% and 28.90% in the ultimate tensile strength, compression strength and hardness of the microwave sintered Al+ 6% Kaoline+ 6% SiC hybrid composite compared to the conventional sintered Al+ 6% Kaoline+ 6% SiC composite. The uniform distribution of SiC and Kaoline reinforcements and no agglomerations were observed in the Scanning Electron Microscopy (SEM) analysis of microwave sintered composite due to the uniform distribution of heat and strong interface bonding in the microwave sintering technique. However, the formation of Al4C3 agglomerations was confirmed in the X-Ray Diffraction (XRD) pattern of conventional sintering composite due to longer sintering periods which deteriorates the mechanical properties of the Al+ 6% Kaoline+ 6% SiC composite. Fractography analysis shows the existence of dimples information on the fractured microwave sintered specimen which reveals the ductile fracture and the presence of intergranular cleavages on the conventionally sintered composite which shows the brittle fracture on the fractured surface. Finally, it was concluded that microwave sintered specimen exhibits superior properties compared to conventional sintered Al+6% Kaoline+ 6% SiC hybrid composite specimen.