Preparation and properties of multilayer graphene reinforced binderless TiC nanocomposite cemented carbide through two-step sintering

Abstract

Material design was performed to solve the twin problems of densification together with brittleness of binderless TiC (BTC). Novel binderless TiC composites reinforced by multilayer graphene (MLG) were fabricated through two-step sintering (TSS) with the auxiliary of nano-sized TiC and WC as sintering aids. The synergistic effects of multilayer graphene and two-step sintering on densification behavior as well as mechanical properties has been investigated. The results demonstrated that excellent mechanical properties were achieved for 0.45 wt% MLG addition with a hardness of 24.36 GPa, a flexural strength of 708.9 MPa as well as a fracture toughness of 7.28 MPa·mm1/2. MLG exerted multifaceted influence on the hybrid TiC-based materials: 1) enhancing the densification and suppressing the grain growth simultaneously; 2) improving the uniform distribution of nano TiC and WC particles throughout the micro TiC matrix; 3) facilitating the load transferring from the matrix to MLG by introducing multi-phase and multi-scale strong-weak hybrid interfaces; 4) inducing efficient toughening mechanisms.