Interface Engineering of Graphene /Copper Matrix Composites Decorated with Tungsten Carbide for Enhanced Physico-Mechanical Properties

For metal matrix composites (MMCs), introduction of low-dimensional nano-carbon materials (NCMs) into three dimensional metallic matrix is commonly applied to enhance mechanical and physical properties of metals and thus significantly extend their wide range applications. However, the interfaces between the NCMs and metal matrix are always a major issue for achieving the best enhancement effects. In this paper, we investigated interfacial structures of graphene nanoplates (GNPs) reinforced Cu matrix composites fabricated using a simple and industrially scalable strategy, through integration of interface engineering design methodology and a spark plasma sintering (SPS) process. We then systematically evaluated their physico-mechanical properties, interfacial characteristics and strengthening mechanisms. The in-situ formed WxCy nano-layers and carbide nanoparticles on the surfaces of GNPs and near the interfaces of Cu grains promote strong interfacial bonding and improves the cohesive strength of Cu based nanocomposites. The GNPs-W/Cu composites show a good balance between strength and electrical conductivity. Their 0.2% yield strength and ultimate tensile strength have been improved up to 239.13% (112.73%) and 197.76% (72.51%), respectively, when compared with those of pure copper (or GNPs/Cu composites). Electrical conductivity of GNPs-W/Cu composites shows no apparent changes after the addition of the GNPs. The dislocation strengthening, refinement strengthening and load transfer strengthening were achieved simultaneously through the engineered interfaces in GNPs-W/Cu matrix composites. This work has provided a new strategy to fabricate high-performance NCMs enhanced MMCs by using the interface engineering methodology.