Microwave sintering of WC-HEA cemented carbide: Sintering process, microstructure and mechanical properties

Microwave sintering is an efficient and green material preparation technology. Ultrafine crystalline WC-CoCrFeNiCu cemented carbide were fabricated by microwave sintering using mechanically alloyed high-entropy alloy (HEA) as a binder. The effects of the microwave sintering process (sintering temperature, holding time) on grain distribution, microstructure and mechanical properties of WC-HEA cemented carbide were studied. WC-10wt%HEA showed the best mechanical properties as sintered at 1400 °C with holding time of 10 min. Its grain size, Vickers hardness and fracture toughness were 273 ± 6 nm, 17.6 ± 0.8 GPa, and 8.7 ± 0.3 MPa·m1/2, respectively. The delayed diffusion effect of HEA played significant role in inhibiting grain growth, resulting in 38% smaller than that of WC-Co cemented carbide. Improving the wettability of HEA on WC to reduce the porosity of the sintered body is the main challenge in producing cemented carbide tool materials with HEA as a binder. •Microwave sintering offers great advantages in terms of lower sintering temperatures and reduced sintering times (at least 60%) compared to traditional sintering method.•HEA has a hysteretic diffusion effect, and the average grain size (273 nm) of WC-HEA cemented carbides prepared with equivalent microwave sintering process parameters is at least 38% smaller than that of WC-Co cemented carbides.•The elements that make up HEA can be replaced with each other to form a solid solution, and the WC-HEA alloy system consists of a WC hard phase, an η-carbide phase, and an FCC-structured HEA binder phase.