Synergistic Effect of Heat Treatment and Graphene/ZrO2 Addition on the Mechanical and Tribological Properties of Al7075-Based Hybrid Composites

Abstract

This research aims to improve the microstructure, mechanical, and tribological behavior of Al7075 aluminum alloy by different ratios of zirconia (ZrO2, 1, 3, 6, and 9 wt%) and graphene nanoplatelets (GNPs, 0.1, 0.3, and 0.5 wt%) reinforcement. Al7075-ZrO2 and Al7075-ZrO2-GNPs composites are produced by a combination of powder metallurgy followed by induction-assisted hot uniaxial pressing techniques. The effect of reinforcement ratio and induction-assisted hot pressing on the density, compressive strength, hardness, wear rate, mass loss, and friction coefficient of Al7075-based composites is evaluated. As a result of the mechanical and tribological investigations, the highest apparent density (2.74 g cm-3), compressive strength (450 +/- 4 MPa), hardness (169 +/- 2 HV), lowest mass loss (0.0014 g), and wear rate (1.0219 x 10-4 mm3 (Nm)-1) are determined for sintered and induction-assisted hot-pressed Al7075-6%ZrO2-0.1%GNPs hybrid composites. Consequently, the combination of reinforcement elements and the induction-assisted hot uniaxial pressing procedure increases the hardness and compressive strength by 17.4% and 57.9%, respectively, while decreasing the mass loss and wear rate by 30% and 33.83%.