The Nanostructured NiFeCrWMo High-Entropy Alloy Binder versus Traditional Co Binder for WC-based Hard Alloys

In this work, two hard alloy systems with a nanostructured NiFeCrWMo high-entropy alloy and ultrafine graded Co as binders, respectively, were obtained by electron beam sintering. X-ray diffraction and microstructural analyses revealed that the nanostructured NiFeCrWMo high-entropy alloy, due to the effect of “sluggish diffusion” and the content of refractory elements, significantly inhibits both the growth of WC grains and its own grain structure, forming thin layers around WC particles without agglomerations of binder particles, pores, or their diffusion into carbide phases. At the same time, the hardness (20.2 GPa vs. 17.5 GPa for the Co binder) and fracture toughness (11.4 MPa.m
^1/2
vs. 9.5 MPa.m
^1/2
for the Co binder) characteristics reflect a significant positive effect of using the nanostructured NiFeCrWMo high-entropy alloy as a binder. Thus, this result opens broad prospects for the further production of these hard alloys with significantly improved characteristics.