Effect of high-entropy alloy binder content on the microstructure, mechanical properties and oxidation behavior of Ti(C,N)-TiB2 cermets

High-entropy alloys (HEA) are characterized by unique composition design concepts and excellent performance. As binders for cermet materials, they have been studied in recent years and have shown broad application prospects. In this study, the microstructure, mechanical properties and high-temperature oxidation behavior of Ti(C,N)-TiB2-HEA composite cermets with different HEA binder contents are investigated. The experimental results indicate that as the HEA content increases from 6 to 14 wt.%, the pores of the composite cermets gradually decrease, and the grain size first increases and then decreases. The hardness of the composite cermets gradually increases, and the bending strength and fracture toughness first increase and then decrease. The highest hardness, bending strength and fracture toughness values are 2008.6 HV10, 727 MPa, and 7.9 MPa m(1/2), respectively. The composite cermets with 14 wt.% HEA binder exhibit superior oxidation resistance. This is because the internal metal atoms diffuse to the surface, which will consume more oxygen and form a dense oxide layer. The diffusion of oxygen to the internal non-oxidized parts will be effectively inhibited. In addition, cracks appear in the oxide layers at 1000 degrees C. As the HEA binder content increases from 6 to 14 wt.%, the cracks gradually disappear during the oxidation process and are replaced by an Al2O3 layer. (C) 2021 The Ceramic Society of Japan. All rights reserved.