OBRABOTKAMETALLOV Vol. 28 No. 3 2026 266 MATERIAL SCIENCE References 1. Yeh J.-W., Chen S.-K., Lin S.-J., Gan J.-Y., Chin T.-S., Shun T.-T., Tsau C.-H., Chang S.-Y. Nanostructured highentropy alloys with multiple principal elements: Novel alloy design concepts and outcomes. Advanced Engineering Materials, 2004, vol. 6 (5), pp. 299–303. DOI: 10.1002/ADEM.200300567. Eff ect of carbon alloying and heat treatment on the microstructure, mechanical properties, and tribological behaviour of a powder-metallurgy CoCrCuFeNi high-entropy alloy (HEA) Pavel Loginov 1, 2, a, *, Alexander Fedotov 1, b, Samat Mukanov 1, c, Bogdan Romanenko 1, d, Yulia Chkannikova 1, e, Nikita Koltsov 1, f, Marina Bychkova 1, j, Olga Manakova 1, h 1 National University of Science and Technology MISIS, 4 Leninsky Prospekt, building 1, Moscow, 119049, Russian Federation 2 Institute of Nanotechnology of Microelectronics of the Russian Academy of Sciences, 32A Leninsky Prospekt, Moscow, 119334, Russian Federation a https://orcid.org/0000-0003-2505-2918, pavel.loginov.misis@list.ru; b https://orcid.org/0009-0009-9208-1453, sashok12221998@mail.ru; c https://orcid.org/0000-0001-6719-6237, smukanov@misis.ru; d https://orcid.org/0009-0003-7470-5185, a.v.d.romanenko@gmail.com; e https://orcid.org/0009-0006-5211-8993, fi restorm567@bk.ru; f https://orcid.org/0009-0007-5410-5915, koltsov02@mail.ru; j https://orcid.org/0000-0002-9233-4707, bychkova@shs.misis.ru; h https://orcid.org/0000-0001-8882-4191, manakova_ol@mail.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2026 vol. 28 no. 3 pp. 250–268 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2026-28.3-250-268 ART I CLE I NFO Article history: Received: 14 May 2026 Revised: 25 May 2026 Accepted: 17 July 2026 Available online: 15 September 2026 Keywords: High-entropy alloys Powder metallurgy Mechanical properties Tribological properties Strengthening mechanism Funding This study was funded by the Russian Science Foundation (Project No. 22-79-10144-P). Acknowledgments The authors express their sincere gratitude to M.I. Petrzhik, Head of the Functional Surfaces Testing Laboratory at NUST MISIS, for assistance with the mechanical property characterization. ABSTRACT Introduction. Powder metallurgy high-entropy alloys (HEAs) of the CoCrCuFeNi system exhibit high strength but low ductility due to their ultrafi ne-grained structure and inhomogeneous distribution of the copper-rich phase. One approach to improve the balance of mechanical properties involves the microaddition of non-metallic elements, particularly carbon, which can enhance both strength and ductility. The purpose of this study is to determine the eff ect of carbon content (0.2–1.0 wt.%) and heat treatment on the phase composition, microstructure, mechanical properties, and tribological behavior of powder metallurgy CoCrCuFeNi HEAs fabricated by mechanical alloying and hot pressing. Materials and methods. The investigation employed X-ray diff raction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), hardness testing, bending testing, tensile testing, and pin-on-plate tribological testing (with Si3N4 as the counterbody). Results and discussion. It is established that carbon is bound into Cr23C6 and Cr2(C,N) phases without altering the ratio of the major phases. Hardness increase from 3.27 to 3.56 GPa, and bending strength increased from 1,440 to 1,620 MPa. For the alloy containing 1.0 wt.% C after annealing, a bending strength of 1,780 MPa, a tensile strength of 1,010 MPa, and an elongation of 2.3% were achieved, whereas the base alloy exhibited brittle fracture at 730 MPa. TEM analysis revealed that carbides are predominantly located at grain boundaries of the matrix (grain size 620–840 nm), facilitating a transition from intergranular cleavage to ductile dimple fracture. The friction coeffi cient (0.75–0.77) is weakly dependent on composition, while the lowest wear is attained after annealing of the carbon-alloyed composition. It is found that alloying with carbon (1.0 wt.%) followed by heat treatment enhances both the strength and ductility of powder metallurgy CoCrCuFeNi HEAs through carbide strengthening and optimization of grain boundary structure. For citation: Loginov P.A., Fedotov A.D., Mukanov S.K., Romanenko B.Yu., Chkannikova Yu.G., Koltsov N.A., Bychkova M.Ya., Manakova O.S. Eff ect of carbon alloying and heat treatment on the microstructure, mechanical properties, and tribological behaviour of a powder-metallurgy CoCrCuFeNi high-entropy alloy (HEA). Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2026, vol. 28, no. 3, pp. 250–268. DOI: 10.17212/1994-6309-2026-28.3-250-268. (In Russian). ______ * Corresponding author Loginov Pavel Alexandrovich, D.Sc. (Engineering), Associate Professor National University of Science and Technology MISIS, 4 Leninsky Prospekt, Bldg. 1, 119049, Moscow, Russian Federation Tel.: +7 916 695-68-07, e-mail: pavel.loginov.misis@list.ru
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