Mechanical Fractography and Worn Surface Analysis of Nanographite and ZrO2-Reinforced Al7075 Alloy Aerospace Metal Composites

In the present research, an effect of nanographite and zirconium oxide (ZrO2) dual reinforcement addition on the mechanical and wear behaviour of Al7075 alloy has been studied. The Al7075 alloy with constant 3 wt.% of graphite particles and varying (3 and 6) weight percentages of ZrO2 particle-reinforced hybrid composites were fabricated by stir casting method. The synthesized dual particle-reinforced Al7075 alloy hybrid composites were subjected to microstructural studies, mechanical and wear properties testing. Microstructural characterizations of obtained samples were carried out by scanning electron microscopy. The graphite and ZrO2 particles were evenly distributed in the Al7075 alloy matrix. The hardness, impact and tensile strength of hybrid composites have been increased with the addition of dual reinforcements. There was slight decrease in the ductility of the Al7075 alloy after the incorporation of these reinforcements. The wear behaviour of the prepared samples was tested at varying loads and speeds. The hybrid composites exhibited a superior wear resistance as compared to base matrix alloy Al7075. Various fracture and wear mechanisms were observed in the Al7075 alloy with graphite and ZrO2 particle-reinforced composites using SEM.