AN INVESTIGATION OF THE MECHANICAL PROPERTIES OF ALUMINIUM SILICON CARBIDE METAL MATRIX COMPOSITE

ABSTRACT

This report presents a comparative study of the mechanical properties of Al 2024-SiC reinforced metal matrix composite and unreinforced Al 2024 alloy. Various mechanical tests were performed on the MMC and the microstructure studied under an optical microscope.

In the study, analysis of the tensile test results revealed lower tensile properties compared unreinforced alloy.  This was because specimen failed at a point of weakness (the junction between the test section and the grip section). Impact test results revealed a decrease of impact energy compared to impact energy of the unreinforced alloy and this was primarily due to addition particles of the reinforcement which are brittle thus lowering the ductile behaviour of the base metal. Hardness test results revealed that the reinforced alloy had a higher hardness value compared to unreinforced alloy.

Microscopic analysis revealed even distribution of reinforcement particles in the matrix at low magnification but at higher magnification, the reinforcement particles appear to be clustered at some regions. This could explain the variation in hardness values from the series of hardness tests carried out on a single specimen.

In general, Metal Matrix Composites are expected to have high strength, low weight to strength ratio, high stiffness and exhibit greater corrosion resistance and wear resistance compared to unreinforced alloys. Such properties are not achievable in monolithic alloys of magnesium, aluminium or titanium.