Densification behavior of ultrafine WC‐based composites with Al x CoCrCuFeNi high‐entropy alloy binders

Abstract Ultrafine WC‐based cemented carbides with 10 wt.%Al x CoCrCuFeNi high‐entropy alloy (HEA) binders were fabricated by spark plasma sintering, and the effects of HEA binders on the densification behavior of the WC‐HEA cemented carbides were studied. The densification of the WC‐HEA cemented carbide, as well as traditional WC‐Co, can be divided into the slow densification stage, rapid densification stage, and final densification stage. The densification behavior of the WC‐HEA cemented carbides largely depends on the performance of the HEA binder during the SPS process. The sluggish diffusion effect of HEA weakens the diffusion of W atom on the powder particle surface and inhibits the growth of WC grain. Consequently, the disappearance of pores in the sintered compact is hindered, which leads to a low relative density of the WC‐HEA cemented carbide. With the increase of Al content, the inhibitory effect of the Al x CoCrCuFeNi binder on the growth of WC grain is suppressed, and an Al‐containing phase with a low melting point is more likely to form. Therefore, the relative density of the WC‐10 wt.%Al x CoCrCuFeNi cemented carbide raises linearly with increasing Al content of the HEA binder.