Mechanical and Tribological Properties of Al–Mg–SiC Metal Matrix Composite for Pistons of Two-Stroke Engine

Abstract

This work is about the tribological and mechanical characterization of aluminium and magnesium metal matrix composite reinforced with silicon carbide (SiC) along with the addition of graphite powder to reduce coefficient of friction and increase lubricity. The Al–Mg MMC is made by squeeze and stir casting method along with the addition of SiC as reinforcement and graphite as a lubricant. Addition of SiC improved the yield strength and tensile strength of the metal matrix composite (MMC). The uniform distribution of the SiC is ensured by fabricating the MMC by squeeze and stirring casting. Magnesium addition to the composite is mainly done to reduce the overall density of the composite. After the fabrication of the MMC, various mechanical tests (like tensile test, hardness test, compression test) and tribological tests (wear test) were conducted to prove the increase in the respective properties. The microstructure and composition of the MMC were analysed using X-ray diffraction and scanning electron microscopy (SEM) techniques. An ANSYS model was also developed at the end to operate a piston with the above composition in the engine operating conditions. Moreover, the mechanical and tribological properties were compared with the original piston material. There was a significant increase in the mechanical properties like tensile strength of the MMC by the addition of SiC as the reinforcement. The hardness value also showed a marginal increase. Tribological property, wear resistance was also increased with the addition of the graphite.