Microstructure and properties of WC-Co/CrMnFeCoNi composite cemented carbides

Abstract A high entropy alloy (HEA, CrMnFeCoNi) was used as the binder for the densification of WC by gas pressure sintering. The HEAs content dependence of microstructure and mechanical properties of WC-Co cemented carbides (with varying Co content according to the HEA content) was investigated. The results show that a small amount of HEA addition (up to 5.0 wt%) can effectively improve the hardness and coercive force of cemented carbide to 92.7 HRA and 14.4 KA⋅m−1, but slightly decreases the fracture toughness. When the HEA content increases to 10.0 wt% (Co content is zero), the density and mechanical properties of the cemented carbide decreases greatly, and some cobalt lakes, pores and η-carbide appear in the microstructure. The measurements of vacuum sintered samples show that the low density and Co lake of partial sample are not caused by pressurized atmosphere, but are actually caused by the poor wettability of HEA and Mn elements. The analysis of the experimental results show that the gas pressure sintering can significantly improve the microstructure and comprehensive properties.