Informatics Publishing Limited

Abstract

Conventional monolithic materials have limitations in achieving good combination of strength, stiffness, toughness and density. To overcome these shortcomings and to meet the ever increasing demand of modern day technology, composites are most promising materials of recent interest. Metal matrix composites possess significantly improved properties high specific strength, specific modulus and good wear resistance compared unreinforced alloy. Among MMC’s aluminium composites are predominant in use due to their low weight and high strength. The Key Features of MMC’s are specific strength and stiffness, excellent wear resistance, high thermal and electrical conductivity. The present investigations aim at the development of A356 aluminium alloy based Rice Husk Ash (RHA) and Al₂O₃ particulate reinforced hybrid metal matrix composites by stir casting route. Tensile strength and Hardness of the hybrid composites have been evaluated. Significant improvement in the properties was been observed with the addition of reinforcement. Further, properties of heat treated composites were enhanced when compared to as cast composites.

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Abstract

In the present work stir casting process was introduced and the commercial A356 aluminium alloy reinforced with RHA/ Al₂O₃ particulates in equal proportions (1wt%, 2wt%, 3wt%, 4wt% and 5wt%) were used for the present study. A356 alloy belongs to a group of hypoeutectic Al-Si alloys and has wide applications in marine and automotive.RHA/Al₂O₃ based A356 hybrid composite is a refractory compound that exhibits outstanding features such as high melting point, high wear and corrosion resistance due to T6 heat treatment. After T6 heat treatment, the microstructures of (RHA/ Al₂O₃) undergo a remarkable change, leading to the improvement of tribological properties of hybrid composites. It was also observed that the density of hybrid composites decreased with increasing particle (RHA/Al₂O₃) content. 

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