Functionally gradient high-entropy cemented carbide with tailored nano reinforcements

Abstract

Structural hierarchy can improve the mechanical responses of materials, meaning that making materials harder and tougher by tailoring the microstructures has been an enduring pursuit in materials science. This is exemplified by the inherent hardness-fracture toughness trade-off of cemented carbides circumvented through introducing microstructural gradients. Advanced cemented carbides must be highly resistant to both deformation and fracture. Herein, the characteristics and stabilization of Co gradient, as well as their influences on the mechanical properties of the high-entropy cemented carbides were investigated in detail for tailoring reinforcements including MLG (multilayer graphene)/MCNT (multiwall carbon nanotube) in surface layer and VC/Cr₃C₂ in the inter and core layers. It is found that the graded HEC (high-entropy carbide)-based cemented carbides afforded enhanced hardness-fracture toughness relationship in comparison with traditional WC-Co, WC-HEA (high-entropy alloy), HEC-Metal and gradient WC-Co, as a function of the combination of high entropy carbide as alternative hard phase to WC, graded structure coupled with hybrid MLG/MCNT reinforcements. This observation provided an avenue for enhancing the mechanical behaviors of other materials as ceramics through tailoring microstructures.