Graphene reinforced medium entropy cemented carbide coupling medium-entropy ceramic and medium-entropy alloy

This study is devoted to the development of medium entropy carbide (MEC) and medium entropy alloy (MEA) as hard and binding phases to enhance the hardness and fracture toughness of cemented carbide, respectively, and the introduction of multilayer graphene (MLG) to further enhance the fracture toughness of cemented carbide. The successful preparation of a (TaZrTi)C-10CoNiFe cemented carbide with high hardness and fracture toughness was achieved through the use of the spark plasma sintering (SPS) technique. This study investigates the microstructure and mechanical properties of medium entropy cemented carbides (MECCs) reinforced with MLG. The optimal sintering temperature for (TaZrTi)C-10CoNiFe MECCs was determined to be 1500°C. The incorporation of MEC led to an enhancement in hardness, while the introduction of MEA resulted in an improvement in fracture toughness and transverse rupture strength (TRS). Moreover, the addition of MLG further enhanced the fracture toughness without significant influence on the cemented carbides. The optimal mechanical responses were achieved for MECC-0.15%MLG with a hardness of 18.73GPa, a fracture toughness of 13.45MPa·m1/2 and a TRS of 1946.2MPa. The principal toughening mechanisms were identified as MLG-induced crack deflection, bridging, branching, and microcracking, as well as MLG walling, MLG bending, and MLG pullout. •Substitutes for WC and Co in WC-Co cemented carbides have proven to be economically and technically feasible.•The medium entropy carbide phase as an alternative hard phase to tungsten carbide and the medium entropy alloy phase as an alternative binder phase to cobalt significantly increase the freedom to tune the microstructure, stability and properties of cemented carbides.•The doping of moderate amounts of multilayer graphene has been demonstrated to significantly enhance the fracture toughness and transverse fracture strength of medium entropy cemented carbide.•The principal toughening mechanisms were identified as MLG-induced crack deflection, bridging, branching, and microcracking, as well as MLG walling, MLG bending, and MLG pullout