Enhanced mechanical behavior and fabrication of graphite flakes covered by aligned graphene nanoplatelets reinforced 2A12 aluminum composites

Abstract

Poor mechanical properties is a key bottleneck limiting the application of graphite (Gr)/Al composites in thermal management structural components. A type of Gr (Graphene Nanoplatelets (GNPs))/2A12Al composites with excellent interface bonding and mechanical properties was developed. In this work, GNPs with height of about 204 nm were grown on the Gr flakes with chemical vapor deposition (CVD) and the Gr (GNPs)/2A12Al bulk composites were consolidated by powder metallurgy technique. The thermal conductivity, flexural strength and tensile strength of the composite were investigated. The results show that interface of the composite is well bonded, meanwhile the hardness and modulus of interface region are enhanced. Thermal conductivity of the composite is improved. Most importantly, the flexural strength and tensile strength are significantly enhanced. The maximum flexural strength reaches 344 MPa and tensile strength reaches 254 MPa when the volume fraction of reinforcement is 15 vol %. The remarkable strengthening effect is mainly attributed to the increase of mechanical locking effect at the interface and load transfer capability. Not only that, there is only a little decrease in flexural and tensile strength even after 200 thermal cycles for Gr (GNPs)/2A12Al composites.