High-hard and high-tough WC-TiC-Co cemented carbide reinforced with graphene

The attainment of both hardness and fracture toughness is the critical requirement for cemented carbides to be applied as structural and functional materials. However, these two properties are usually mutually exclusive. Traditional toughening methods as particle-dispersion, phase-transformation and whisker toughening usually impact the hardness adversely. This work was undertaken to develop a high-hard and high-tough cemented carbide through introducing multilayer graphene (MLG) as well as single layer graphene (SLG) as the reinforcing phase. The microstructure together with mechanical properties of the graphene reinforced cemented carbides was evaluated and compared. MLG exhibited a more favorable dispersion property in cemented carbide matrix than SLG. SLG addition was beneficial for increasing fracture toughness without appreciable influence on the hardness of cemented carbides, while MLG doping simultaneously enhanced the fracture toughness and hardness of the hardmetal with a fracture toughness of 13.2 MPa m^1/2, a hardness of 2057.2 kgf/mm² and a transverse rupture strength of 1709.2 MPa. This toughening mechanism constitutes a step forward in developing high-tough and high-hard cemented carbide matrix composites to be applied for structural as well as functional applications.