Investigation of Mechanical and Tribological Properties of Al7075-Al2O3-GNPs Hybrid Composites Produced by Powder Metallurgy and Induction Hot Pressing

Abstract

Although aluminum and its alloys have lightweight and high formability, their low wear resistance and mechanical properties limit their applications compared to other metals. In this study, different ratios of alumina (1-15 wt.%) and graphene nanoparticles (0.1-0.5 wt.%) were reinforced with the aim of increasing the mechanical and tribological properties of Al7075 aluminum alloy. The production of Al7075-Al₂O₃ and Al7075-Al₂O₃-Graphene composites was carried out by powder metallurgy and induction hot pressing methods. The effects of induction hot pressing and Al₂O₃ and graphene content on the microstructure, mechanical, and tribological properties were investigated. In the study, SEM, SEM-EDX, and XRD were used for the microstructure analyses. The mechanical and tribological tests consist of density measurement, compression test, Vickers hardness test, and pin-on-disk wear test. As a result, the highest apparent density (2.72 g/cm³), hardness (178 ± 1 HV), compressive strength (486 ± 4 MPa), the lowest weight loss (0.001 g) and wear rate (7.5 × 10⁻⁵ mm³/(Nm)) were obtained in sintered and induction hot-pressed Al7075-12Al₂O₃-0.1 graphene composites. Consequently, the induction hot pressing and reinforcements (Al₂O₃ and graphene) improved the hardness, compressive strength, weight loss, wear rate, and coefficient of friction by 48.4%, 70.5%, 66.7%, 21.9%, and 54.2%, respectively.