Crack propagation and mechanical behavior prediction of graphene reinforced functionally gradient high-entropy cemented carbides

High hardness and high toughness are always the permanent goal in cemented carbide system. Herein, high entropy carbide (HEC) and high entropy alloy (HEA) were proposed to replace traditional hard phase as WC and binder phase as Co, respectively, developing functionally gradient high-entropy cemented carbides (FGHCCs) through microstructure simulation of and properties prediction. Moreover, graphene (G) was doped to further the mechanical properties of FGHCCs. The results demonstrated that graphene reinforced FGHCC exhibited simultaneously enhanced hardness, fracture toughness and flexural strength compared to graded WC-Co. The principal toughening mechanisms were determined as graphene induced crack bridging, crack deflection, and crack stopping, while the major hardening mechanisms were ascertained as high entropy effect, gradient structure and grain refinement. This research presents the enormous potential for the microstructure and properties tailoring of cemented carbides through controlling the compositions of HEC and HEA.