Microstructure and Mechanical Properties of WC-10wt.%AlCoCrFeNi Cemented Carbides Fabricated by Plasma-Assisted Ball Milling

In this study, an AlCoCrFeNi high-entropy alloy (HEA) synthesized via gas atomization serves as a replacement binder phase, with WC-10wt.% HEA cemented carbide prepared through plasma milling and low-pressure sintering. The microstructure of WC-10wt.% HEA cemented carbides was analyzed utilizing XRD, SEM, and HRTEM. The results show that the WC-10wt.% HEA carbide combines moderate hardness and excellent toughness, achieving 1613 HV30 and 13.4 MPa·m1/2, respectively, with a transverse rupture strength of 1759 MPa. The formation and growth of low-energy ∑2 WC/WC grain boundaries and plate-like WC, coupled with the improvement of toughness in the HEA binder phase with a FCC structure, being the causes of these exceptional mechanical qualities. Furthermore, Cr in HEAs promotes (W,Cr)C_x complexion at the WC/HEA interface, effectively inhibiting WC grain growth. However, ball milling induces a structural change in the AlCoCrFeNi alloy from BCC to FCC by desorbing Al, potentially leading to the formation of cavity phases in the WC-10wt.% HEA cemented carbide.