Towards high performance GNFs/Ti composite through simultaneously manipulating laminated microstructure and interface reaction

Bulk graphene nano-flakes (GNFs)-reinforced Ti matrix composite (GNFs/Ti) was obtained by laminated microstructure design. By means of a novel flake powder assembly approach, the GNFs possessed high compatibility with Ti flakes and achieved uniform dispersion in matrix. Powder mixtures were consolidated through low-temperature sintering and short-time heat treatment strategy to simultaneously manipulate the interface reaction and microstructure. Compared with the unreinforced Ti matrix, GNFs/Ti composites were shown to obtain significantly improved strength. Specially, the 0.46 vol% GNFs/Ti composite heat-treated at 1023 K for 450s exhibited the exceptional well ductility with a superior high compressive yield strength of ~2 GPa, which was interpreted by the strong GNFs-Ti interface, and the extrinsic toughening effect as a result of the laminated microstructure and improvement of matrix grain bonding. This work provided a feasible way to construct the high performance nano-carbon reinforced Ti-based composites, and underscore the importance of interface reaction and microstructure design for achieving the well strength-ductility combination.