Synergistic strengthening effect of alumina anchored graphene nanosheets hybrid structure in aluminum matrix composites

Abstract

The microstructure design of graphene based reinforcement is an effective route to obtain graphene/aluminum composites with good mechanical properties. In this study, alumina anchored on graphene nanosheets hybrid (Al2O3@GNS) was in situ synthesized by a sodium chloride template-assisted high-temperature calcination strategy. Al2O3@GNS was used as a reinforcement to fabricate aluminum matrix composites (Al2O3@GNS/Al) by flake powder metallurgy (FPM) route. It was found that Al2O3@GNS was homogenously distributed and a relatively obvious synergistic strengthening effect was acquired by employing Al2O3@GNS as reinforcement of the composites. ∼1.0 vol%-Al2O3@GNS/Al composite obtained the maximum tensile strength of 359 MPa, an ∼131.6% improvement superior to pure Al. The strengthening efficiency of Al2O3@GNS is higher than those reinforced by individual GNS, Al2O3 or its simple mixture. An elongation of 11.2% was achieved in the ∼ 1.0 vol%-Al2O3@GNS/Al composite, exhibiting a favorable strength-ductility synergy. The synergistic strengthening effect was attributed to the formation of an interlocked network of Al2O3@GNS, which was beneficial to improve the load transfer efficiency from the matrix to reinforcement in the composites.