Effect of graphene on the tribolayer of aluminum matrix composite during dry sliding wear
Aluminum-graphene nanosheets (GNSs) composite was fabricated and subjected to dry sliding wear tests. A protective and lubricious tribolayer was formed between the sliding interfaces. SEM, TEM and Raman microscopies were used to characterize the cross section and top surface of the tribolayer, for the purpose of understanding the effect of GNSs on the microstructure of the tribolayer and induced tribological performance. It was found that the incorporation of 1 vol% GNSs reduced the wear and friction by 85.0% and 39.1% respectively. GNSs strengthen the formation of the protective tribolayer by wrapping sliding surface debris particles and bridging subsurface cracks. Raman mapping results indicate that the GNSs-rich tribofilms are smeared on the wear scar along the sliding direction. GNSs are self-lubricating for their ease of interlayer sliding and formation of rollers during sliding wear, which enable the reduction in friction.