Experimental study on properties of Al–Al2O3 nanocomposite hybridized by graphene nanosheets

Abstract

In this study, Al–Al2O3–Ag coated graphene hybrid nanocomposites was fabricated by Electroless coating and powder metallurgy. Electro-less deposition was used to coat graphene nanosheets (GNs) with a thin layer (~5 nm) of Ag. We studied the impact of GNs content on the structural, microhardness and wear properties of the manufactured hybrid nanocomposites. The energy dispersive X-ray (EDX) mapping images reveal that the Al2O3 and GNs reinforcements particles were homogeneously distributed into the Al matrix. The relative density decreased with increasing the weight fraction of GNs contents. The results showed that hardness and wear properties were improved with increasing GNs mass fraction. Vickers microhardness tests results showed that the highest hardness value of 130.5 HV is attributed to the sample containing 1% of GNs, much higher than the hardness value of the Al-5% Al2O3 composite of 48 HV. The wear test results showed that the composite with higher GNs content 1 wt.% showed the best wear resistance. The high strength and self lubricant properties of GNs and the grain size reduction due to electroless deposition were the main reason for properties improvement. Additionally, the increased efficient transfer of stresses due to the curled structure of GNs helps for properties improvement.