Mechanical and Tribological Characterization of a Novel Hybrid Aluminum/Al2O3/RGO Composite Synthesized Using Powder Metallurgy

Recently, graphene has lent itself as a promising additive to obtain aluminum-based matrix composites of superior mechanical strength and outstanding wear resistance. In this investigation, composite samples are synthesized by adding reduced graphene oxide (RGO) and alumina (Al 2 O 3 ) particles to aluminum metal matrix via powder metallurgy technique. RGO is fabricated using modified hammer's method and characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and FTIR (Fourier Transform Infrared). The synthesized composite samples are tested in wear using a developed pin on disk test setup. The microstructure of each sample is examined using optical microscope as well as SEM, while the hardness values are measured using Vickers microhardness tester. Experimental results clearly indicate that adding RGO to the aluminum matrix considerably enhances its wear resistance when compared to Al 2 O 3 additive, i.e., the results prove superior lubricant characteristics of graphene. In addition, hybrid composite specimens from Al 2 O 3 and graphene demonstrate remarkably higher hardness values than those reinforced by each single additive. Increasing Al 2 O 3 wt.% results in a considerable agglomeration of particles leading to deterioration of the mechanical and tribological properties in both hybrid and single additive specimens. In the investigated range, the highest hardness and wear resistance are manifested by hybrid composite containing 0.3 wt.% RGO and 5 wt.% Al 2 O 3 .