WC-based cemented carbide with NiFeCrWMo high-entropy alloy binder as an alternative to cobalt

• Published in: Vacuum 2024-04, Vol.222, p.113052, Article 113052
• Main Authors: Nakonechnyi, S.O., Yurkova, A.I., Loboda, P.I.
• Format: Article
• Language: English
• Subjects: Cemented carbides; Electron beam sintering; Fracture toughness; Hardness; High entropy alloy; Nanostructured binder
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2024.113052

In the current work, a nanostructured NiFeCrWMo high entropy alloy (HEA), synthesized by mechanical alloying, was used as the alternative binder phase for substituting Co to fabricate WC–HEA cemented carbides by electron–beam sintering (EBS). The microstructure and mechanical properties of initial powder mixtures and sintered samples were studied using X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS), indentation technique and compression tests. NiFeCrWMo HEA does not have direct interaction with WC, but at the boundaries between WC and HEA particles (Ni, Fe, Cr)xWyCz complex carbide is formed as result of reduction processes during sintering. The results show that WC–HEA cemented carbide has better performances than the commercial WC–8Co-cemented carbide prepared by EBS. The NiFeCrWMo HEA binder significantly slows down the growth of WC grains due to the sluggish diffusion effect and the formation of a small amount of complex carbide, and, compared to Co, improves the mechanical properties, provides an excellent combination of microhardness (18.9 ± 0.4 GPa) and fracture toughness (11.4 ± 0.3 MPa m1/2). Therefore, the NiFeCrWMo high entropy alloy can potentially become a binder for WC cemented carbides. •WC grain growth can be considerably inhibited by the NiFeCrWMo high-entropy alloy.•A small amount of (Ni,Fe,Cr)xWyCz carbide formed during electron-beam sintering.•High microhardness of 18.9 GPa and fracture toughness of 11.4 MPa m1/2 are obtained.