Al matrix composites reinforced by in situ synthesized graphene-Cu hybrid layers: interface control by spark plasma sintering conditions

Tremendous impacts are usually made by the synthesis method and consolidation technique on microstructure and interface of graphene/Al composites. In the present work, an in situ gel-precursor decomposition route is proposed for the one-step synthesis of graphene nanosheet (GNS) decorated with Cu nanoparticles in the form of hybrid layers encapsulating Al grains (designated as GNS-Cu/Al). Consolidation is performed by spark plasma sintering (SPS) using markedly different sets of maximum temperature and maximum uniaxial pressure (400 degrees C/400 MPa or 500 degrees C/100 MPa). The powder and dense samples are investigated by several techniques including thermal analysis, X-ray diffraction and electron microscopy. The microhardness and elastic modulus of selected GNS-Cu/Al composites are investigated and related to the microstructure and preparation conditions. Results demonstrate that the interface structure is primarily determined by the roles of GNS-Cu hybrid layers and finely controlled by SPS conditions. This work paves a novel way to elucidate the evolutions of metal-decorated graphene hybrids in Al matrix composites. [GRAPHICS] .