Study on Effect of High-Entropy Alloy Binder on Microstructure and Properties of WC Cemented Carbide Doped with Rare Earth Oxide

Abstract

The AlCoCrFeNi powder was added to WC powder as a binder and Y2O3/ZrO2 was doped by the wet chemical method as grain-growth inhibitors. The WC-Y2O3-ZrO2-10AlCoCrFeNi composite powders were sintered by spark plasma sintering to obtain an alloy. The microstructure and properties of the cemented carbide were studied. The result showed that the rare-earth-oxide (Y2O3/ZrO2)-refined grain size of the alloy and the high-entropy alloy binder provided the alloy with better hardness and toughness. The AlCoCrFeNi diffused slowly between the WC grains because of a delayed diffusion effect and Cr having a low affinity for the WC matrix. During the dynamic process of the WC particles’ dissolution and precipitation growth, the Fe, Co, and Ni that had a better affinity for the WC matrix diffused and distributed more smoothly, which increased the strength and toughness of the alloy. When the temperature of the SPS sintering was 1250 °C, the WC-Y2O3-ZrO2-10AlCoCrFeNi cemented carbide had the best properties, which was a Vickers hardness of 1888.14 HV and a fracture toughness of 14.76 MPa·m1/2.