Design, fabrication and characterization of multi-layer graphene reinforced nanostructured functionally graded cemented carbides

Effect of predesigned multi-layer graphene (MLG) gradient on the microstructure as well as mechanical properties of MLG/WC-Co hardmetal has been investigated. Varied organic solvents and surfactants were used to identify the best combination of dispersing medium and dispersant for the dispersion of MLG. Six kinds of designed functionally graded MLG/WC-Co alloys were prepared employing two-step sintering (TSS) method. Results demonstrated that MLG can enhance the densification process and inhibit the grain growth. Meanwhile, MLG with a predesigned gradient opposite the predesigned cobalt gradient can maximally enhance the stability of predesigned cobalt gradient during liquid phase sintering, the generation of residual surface compressive stress and the mechanical properties of MLG/WC-Co composite. The enhancing mechanisms of cobalt gradient stability were systematically discussed by combining theoretical consideration with experimentation. (C) 2018 Elsevier B.V. All rights reserved.