OBRABOTKAMETALLOV Vol. 24 No. 1 2022 58 MATERIAL SCIENCE References 1. Konstanty J. Powder metallurgy diamond tools. Oxford, Elsevier, 2005. 152 p. ISBN 978-1-85617-440-4. DOI: 10.1016/B978-1-85617-440-4.X5077-9. 2. Novikov M.V., Mechnyk V.A., Bondarenko M.O., Lyashenko B.A., Kuzin M.O. Composite materials of diamond−(Co–Cu–Sn) system with improved mechanical characteristics. Part 1. The infl uence of hot re-pressing Effect of mechanical activation of tungsten powder on the structure and properties of the sintered Sn-Cu-Co-W material Alexander Ozolin a, *, Evgeny Sokolov b Kuban State Technological University, 2 Moskovskaya St., Krasnodar, 350072, Russian Federation a https://orcid.org/0000-0002-0173-1716, ozolinml@yandex.ru, b https://orcid.org/0000-0002-7229-228X, e_sokolov.07@mail.ru Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2022 vol. 24 no. 1 pp. 48–60 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2022-24.1-48-60 Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov ART I CLE I NFO Article history: Received: 14 October 2021 Revised: 02 November 2021 Accepted: 07 December 2021 Available online: 15 March 2022 Keywords: Mechanical activation Nanoparticles Tungsten Liquid phase sintering Metallic binders Diamond abrasive tools Funding The research was carried out with the fi nancial support of the Council for Grants of the President of the Russian Federation for state support of young Russian scientists and for state support of leading scientifi c schools of the Russian Federation, No. SP-5863.2021.1. ABSTRACT Introduction. One of the methods for improving the properties of sintered materials is mechanical activation of powders. It ensures milling the powders, changing its energy state, intensifying the sintering of powder materials, and forming a fi ne-grained structure in it. When tungsten powders are mechanically activated in planetary centrifugal mills, nanoparticles can be formed, which have a high reactive power. The objective of the paper is to study the effect of mechanical activation of tungsten particles on the structure and properties of the sintered Sn-Cu-Co-W powder material. Research technique: Mechanical activation of W16,5 grade tungsten powder is carried out in a planetary centrifugal ball mill AGO-2U for 5…120 minutes with carrier speeds of 400…1,000 rpm. The mixture of tungsten, tin, copper, and cobalt powders are compacted by static pressing in molds and then sintered in vacuum at 820 °C. The morphology and size of powder particles, as well as the structure of the sintered samples, are studied by scanning electronic microscopy, X-ray microanalysis, and optical metallography. Porosity of the sintered samples is identifi ed by the gravimetric method. Microhardness of the structural constituents and macrohardness of the sintered materials are measured, too. Results: in the modes under study, mechanical activation is accompanied by the formation of tungsten nanoparticles with the minimum size of 25 nm. Alongside this, the powder is exposed to cold working, which hinders further milling. Tungsten nanoparticles, characterized by high surface energy, have a signifi cant effect on the dissolution-precipitation of cobalt during liquid-phase sintering of Sn-Cu-Co-W powder material. Addition of nanodispersed tungsten into the material slows down the growth of cobalt particles during sintering and contributes to the formation of a fi ne-grained structure. The sintered Sn-Cu-Co-W material, containing mechanically activated tungsten, features higher hardness of 105…107 HRB, which is explained by cold working of tungsten particles and dispersion hardening. The results can be applied for improving mechanical properties of Sn-Cu-Co-W alloys used as metallic binders in diamond abrasive tools. For citation: Ozolin A.V., Sokolov E.G. Effect of mechanical activation of tungsten powder on the structure and properties of the sintered Sn-Cu-Co-W material. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2022, vol. 24, no. 1, pp. 48–60. DOI: 10.17212/1994-6309-2022-24.1-48-60. (In Russian). ______ * Corresponding author Ozolin Alexander V., junior researcher Kuban State Technological University 2 Moskovskaya St., 350072, Krasnodar, Russian Federation Tel.: 8 (918) 058-56-54, e-mail: ozolinml@yandex.ru
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