Effect of graphene nanoplatelets on the physical and mechanical properties of Al6061 in fabricated and T6 thermal conditions

Abstract

Abstract Lightweight aluminium matrix composites find wide applications in automobile and aerospace sector. Aluminium alloy composites with graphene nanoplatelets (GNPs) were prepared by powder metallurgy route containing four different loadings, i.e. 0.1\u202fwt%, 0.5\u202fwt%, 1\u202fwt% and 3\u202fwt%. Two methods for exfoliation of GNPs were employed to achieve uniform dispersion in Al6061 matrix. Pressureless consolidation followed by sintering was carried out to obtain near-theoretical densities. Comparison of the fabricated thermal condition and artificially aged T6 samples was carried out to investigate the contribution of GNPs in the strengthening of Al6061 matrix. Microstructure evolution was confirmed by X-ray diffraction, optical and scanning electron microscopy. Electrical conductivity increased with increasing content of GNPs up to 1\u202fwt% due to conductive network around the matrix grains. Mechanical properties were found to increase 93%, 61% and 92% in hardness, compression strength and flexural strength up till 1\u202fwt% GNPs in matrix alloy. Agglomeration at 3\u202fwt% GNPs resulted in deterioration of properties. The fractured surfaces were examined to determine the change in fracture morphology, associated strengthening mechanism and behaviour of GNPs.