The microstructures and mechanical properties of graphene-reinforced titanium matrix composites

This study uses spark plasma sintering (SPS) to prepare graphene nanoplatelet (GNP)-reinforced titanium matrix composite materials. Heat treatment is used during rolling and annealing (R&A) to enhance the interfacial bonding strength between the graphene and titanium crystal grains, uniformly disperse the graphene and refine the grains. Studies have shown that the relative density (RD) of composites increased from 84% to 98% as the processing temperature increased from 600 °C to 1100 °C. Under the optimized plasma sintering process parameters, the best solid-phase reaction temperature is 850 °C, and the tensile strength at room temperature after R&A can reach 1206 MPa for 0.3 wt% GNP titanium matrix composites; this result represents an increase of 46% compared with pure titanium (PTi) under the same conditions. The reduction of area (ψ) of the 0.3 wt% GNP titanium matrix composite can reach 48%. The strengthening mechanisms include composite, grain and second-phase strengthening, wherein composite strengthening is the controlling factor. Additionally, the strength of composites at 1100 °C also increases, but ψ remains a lower level. The formation of nanocarbide particle layers causes a significant reduction in ψ. [Display omitted] •The prepared graphene and the CPTi were used to create composites by SPS.•The microhardness in the ROD was the lowest among the three directions After R&A.•After R&A, the 0.3 wt% graphene composites at 850 °C possessed excellent mechanical properties.•Graphene reacted with Ti to form a large amount of titanium carbide particle layers at 1100 °C.