Microstructures and Properties of WC-10 wt.%CoCrFeNiAl_x Composite Cemented Carbides

In this paper, WC-10 wt.%CoCrFeNiAlx cemented carbide was prepared by a vacuum pressureless tube furnace using the high-entropy alloy CoCrFeNiAlx (x = 0, 0.25, 0.5, 0.75, 1.0) as the binder phase. The effects of Al content changes on the microstructures and mechanical properties of cemented carbides were analyzed. The results showed that the high-entropy alloy as the binder phase could significantly refine the grain size of WC and enhance its mechanical properties. With increasing Al content, the densification of cemented carbide decreased gradually, but the hardness increased gradually; moreover, the fracture toughness and flexural strength appeared to first increase and then decrease. When the Al content was x = 1.0, the densification was the lowest, but the hardness reached a maximum value of 1898.5 MPa, and the fracture toughness and flexural strength reached relatively low values of 7.76 MPa m(1/2) and 680 MPa, respectively. When the Al content was x = 0.25, the hardness value reached 1822.4 MPa, and the fracture toughness and flexural strength reached 10.72 MPa m(1/2) and 1350 MPa, respectively; this composite exhibited optimal overall performance and had the potential to replace Co as a new binder phase.