Investigation of Mechanical Properties of Aluminum Composite (Al-7075/WC& Fly-Ash) Fabricated by Stir Casting Process

This present investigation deals with the variation of mechanical properties of Al-7075 (WC and fly-ash) - a hybrid metal matrix composite prepared by using Al-7075 as matrix with Tungsten Carbide and fly ash as its primary and secondary reinforcements. The main objective of this work is to evaluate the effectof adding Tungsten Carbide (WC) and fly-ash to Al-7075 alloy by performing some mechanical tests. The volume fraction of reinforcements used was 2.5, 5.0 and 7.5 wt. % of WC and fly-ash correspondingly. The technique used for fabrication of this hybrid compositewas stir casting and the reinforcements were added into the molten metal at 803⁰C (optimum). The composites fabricated were then machined according to ASTM dimensions as required for the mechanical tests. From the mechanical tests performed it was found that the hardness values and the toughness values increasedand the tensile strength decreased upon the addition of WC and fly-ash into the aluminium matrix. The improved values of hardness and toughness were because of uniform distribution and the decrease of tensile strength was due to the porosity which was clearly seen in the SEM image of the samples taken.