High-Entropy-Alloy CoFeNiCr Bonded WC-Based Cemented Carbide Prepared by Spark Plasma Sintering

A WC-based cermet bonded by high-entropy-alloy CoFeNiCr was successfully fabricated by spark plasma sintering. The densification behavior, phase constitution, microstructure and mechanical properties of WC-CoFeNiCr/Co composites were investigated. After 5 minutes sintering at 1200 degrees C, the high-entropy-alloy CoFeNiCr binder retains an fcc structure without reacting with WC, and the WC-CoFeNiCr specimens show dense microstructure. At room temperature, the WC-10 wt pct CoFeNiCr specimen possesses hardness and fracture toughness of HV30 18.95 GPa and 15.88 MPa center dot m(1/2), which are 11.6 and 7.6 pct higher than those of the WC-10 wt pct Co specimen. Especially at 600 degrees C, the WC-CoFeNiCr specimen has superior hardness, which is 29 pct higher than that of the WC-Co. The high softening resistance of the WC-CoFeNiCr composite at elevated temperature should be mainly attributable to the diffusion retardation of the CoCrFeNi binder.