Enhanced mechanical properties of few-layer graphene reinforced titanium alloy matrix nanocomposites with a network architecture

Abstract

Few-layer graphene (GR) reinforced Ti6Al4V (TC4) alloy matrix nanocomposites with 3D network architecture were fabricated through spark plasma sintering (SPS) technique. This was done using spherical TC4 particles and 3–5 layered GR powders. GRs were adopted onto the surfaces of the TC4 particles through a chemical modification method. Partial GRs were retained and some titanium carbide (TiC) phases in nanoscale were in-situ generated through a reaction between the GR and TC4 matrix during the sintering stage. The well-dispersed GR/TiC hybrid reinforcements at the TC4 spherical matrix formed a 3D network architecture. Compared with pure TC4, the GR/TC4 composites exhibited higher compressive strength and ductility when the GR concentration was <0.5 wt%. In light of tensile results, the 0.25 wt% GR/TC4 composites showed improved tensile strength with acceptable tensile ductility. The enhanced mechanical properties can be attributed to the network interface strengthening mechanism and matrix grain refinement in the network. The factors affecting mechanical properties of the network structured GR/TC4 nanocomposites were discussed. The conflict between strength and ductility in metallic materials is a vital problem. A good balance of strength and ductility was achieved in the GR/TC4 composites by controlling the GR distribution state in a network architecture.