EVALUATION OF THE MECHANICAL PROPERTIES OF REINFORCED ALUMINIUM (6063) COMPOSITES USING SILICON CARBIDE AND SILICA SAND

Abstract

The production and investigation of the physical and mechanical properties of reinforced Al (6063) composites using silicon carbide and silica sand. The silica sand was obtained from Igbokoda silica sand deposit and processed following standard procedures while the silicon carbide was procured from PASCAL Scientific Company in Akure. Al6063 was obtained from NIGALEX in Lagos. A two-step stir-casting process was adopted for the production of the composites. Composites of volume fractions 6, 7, 8 and 10% were produced using silica sand and volume fractions of 5, 6, 8 and 10% using silicon carbide. The following properties, density, % porosity, modulus of elasticity, yield strength, ultimate tensile strength, hardness, % elongation and impact strength were measured. Metallogragraphic works were carried to examine the as-cast structures. For both types of reinforcements the results showed that the Young’s modulus of elasticity, yield strength, ultimate tensile strength and hardness of the composites increased appreciably with increasing volume fractions of reinforcement particles. Reinforcement with silicon carbide particles was significantly more effective. As expected, ductility and impact energy were reduced. However the density decreased and porosity increased gradually for up to 5% volume of reinforcement additions beyond which the changes were sharp. On the basis of 4% porosity, only 8% volume of silica sand particles and 10% of silicon carbide particles were allowed. The increase in the mechanical properties for silica sand reinforcement at 8% volume addition compared very favourably with those obtained for 8% volume silicon carbide reinforcement. However at 10% volume limit for silicon carbide addition, the increases were remarkably high. This work has produced silica sand particle-reinforced Al6063 composites with mechanical properties comparable with those of very expensive and not readily available silicon carbide particle-reinforced Al6063