Mechanical and Wear Behavior of Al7075 - Graphite Self-Lubricating Composite Reinforced by Nano-WO<sub>3</sub> Particles

Abstract

Al7075 hybrid nanocomposites considered one of the most material utilized in modern engineering applications that required a combination of superior properties such as lightweight, high strength, excellent corrosion resistance, and high thermal conductivity. In the current study, Al7075 – 5 vol % graphite self-lubricating composite was reinforced by 0, 1.5, 2.5, 3.5, and 4.5 vol % WO3 nanoparticles in order to study the microstructural, mechanical, and wear characteristics. The classical powder metallurgy route was employed to fabricate the hybrid nanocomposites specimens. The microstructural analysis of the nanocomposites was characterized by utilizing a Field Emission Scanning Electron Microscope (FESEM) and Energy-Dispersive X-ray (EDX) analyses. Mechanical properties such as micro-hardness and diametral compressive strength were studied. Dry sliding wear test was performed under the various loads of 10, 15, 20, and 25 N at a sliding distance and sliding speed of 1810 m and 1.5 m/s, respectively. Results have revealed that the microhardness and diametral compressive strength considerably improved by increasing the WO3 content until 3.5 vol % and then slightly decreased. Besides, both the values of the wear rate and friction coefficient gradually reduced by increment the reinforcement content up to 3.5 vol % and then suddenly increases for all the applied loads. Nevertheless, the wear rate and friction coefficient were correlated positively with the applied loads. From the results obtained, graphite as solid lubricating material with WO3 nanoparticles was successfully combined into the Al7075 alloy matrix. The optimum mechanical and wear performance of the hybrid nanocomposite were revealed at 3.5 vol % content of WO3 nanoparticles.