Production of wear-resistant boride cermets based on high-entropy CoCrCuFeNi alloy by hot pressing

Abstract

This study is devoted to the production of ceramic matrix composite materials based on borides with a binder made of a high-entropy alloy CoCrCuFeNi using powder metallurgy methods. The composite materials were synthesized by hot pressing of powder mixtures after high-energy ball milling in planetary centrifugal mills. The ceramic matrix of the composites was based on borides (Cr₄B, Cr₂B, CrB, and Ni₃B), while the metallic binder consisted of a solid solution of all metallic components, with a face-centered cubic crystal lattice. The resulting boride-based cermets are characterized by a combination of high hardness, strength, and ductility. With a boron content of up to 20 wt. %, the cermets were comparable in strength to the high-entropy alloy CoCrCuFeNi (1600 MPa) with a hardness of up to 8.34 GPa. The wear resistance of the developed cermets correlates with the boron content and the proportion of boride phases. Samples with a boron content of 40–50 wt. % demonstrate extremely high wear resistance, with a friction coefficient of approximately 0.5 when paired with Al₂O₃.