OBRABOTKAMETALLOV Vol. 27 No. 3 2025 47 TECHNOLOGY References 1. Sadashiva M., Sheikh M.Y., Khan N., Kurbet R., Gowda T.D. A review on application of shape memory alloys. International Journal of Recent Technology and Engineering (IJRTE), 2021, vol. 9 (6), pp. 111–120. DOI: 10.35940/ ijrte.F5438.039621. Production of rods and sheets from TiNiHf alloy with high-temperature shape memory eff ect by longitudinal rolling and rotary forging methods Roman Karelin a, *, Viktor Komarov b, Vladimir Cherkasov c, Artem Osokin d, Konstantin Sergienko e, Vladimir Yusupov f, Vladimir Andreev g A.A. Baykov Institute of Metallurgy and Materials Science of the Russian Academy of Sciences, 49 Leninsky Ave., Moscow, 119334, Russian Federation a https://orcid.org/0000-0002-4795-8668, rdkarelin@gmail.com; b https://orcid.org/0000-0003-4710-3739, vickomarov@gmail.com; c https://orcid.org/0000-0002-5450-3565, cherkasov.vv@misis.ru; d https://orcid.org/0009-0008-4945-3648, art.osokin1201@icloud.com; e https://orcid.org/0000-0003-4018-4599, shulf@yandex.ru; f https://orcid.org/0000-0002-0640-2217, vsyusupov@mail.ru; g https://orcid.org/0000-0003-3937-1952, andreev.icmateks@gmail.com 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. 2025 vol. 27 no. 3 pp. 37–49 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2025-27.3-37-49 ART I CLE I NFO Article history: Received: 07 July 2025 Revised: 28 July 2025 Accepted: 07 August 2025 Available online: 15 September 2025 Keywords: Shape memory alloy Rolling Hardness Rotary forging Funding The study was conducted with the fi nancial support of the State Task of IMET RAS on 2025 year № 07500319-25-00. ABSTRACT Introduction. Ti-Ni based shape memory alloys (SMAs) are functional materials that fi nd widespread practical application in engineering and medicine. Functional properties of Ti-Ni based alloys are sensitive to the chemical composition. To develop alloys with specifi c properties, ternary SMAs are being actively developed. For example, TiNiHf ternary alloys are characterized by a high-temperature shape memory eff ect. Today, there is a demand for SMAs used in the production of functional elements with a response temperature of more than 120 °C. These alloys must also have suffi cient ductility to obtain deformed semi-fi nished products for the subsequent manufacture of heat-sensitive functional elements. Also among the current issues of developing the practical application of TiNiHf alloys is the lack of technological schemes for obtaining semi-fi nished products from TiNiHf SMAs. The purpose of this work is study the feasibility of conducting deformation processing of the studied TiNiHf alloys with a hightemperature shape memory eff ect and to identify the relationships between phase composition and mechanical characteristics and the applied processing method. In this work, the possibility of producing sheets and rods from TiNiHf alloys with 5 and 10 at.% Hf and 50.0 at.% Ni by longitudinal rolling, caliber rolling, and rotary forging was investigated. The research methods were: X-ray analysis, diff erential scanning calorimetry, and measurement of Vickers hardness. Results and discussion. It was found that the TiNiHf alloy with 10 at.% Hf has insuffi cient ductility. From the alloy with 5 at.% Hf, blanks in the form of sheets and rods of various sizes were obtained by using longitudinal rolling and rotary forging processes. It was shown that hot deformation allows increasing the hardness of the studied TiNiHf alloy with 5 at.% Hf compared to the cast state, from 232 HV to 242–264 HV. Cold deformation leads to a signifi cant increase in hardness values up to 362–394 HV. Characteristic temperatures of the forward and reverse martensitic transformation are quite stable. The obtained results indicate the potential of using longitudinal rolling and rotary forging to obtain semi-fi nished products of TiNiHf alloys with 5 at.% Hf and to improve the functional and mechanical properties of the alloy after smelting. For citation: Karelin R.D., Komarov V.S., Cherkasov V.V., Osokin A.A., Sergienko K.V., Yusupov V.S., Andreev V.A. Production of rods and sheets from TiNiHf alloy with high-temperature shape memory eff ect by longitudinal rolling and rotary forging methods. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2025, vol. 27, no. 3, pp. 37–49. DOI: 10.17212/1994-63092025-27.3-37-49. (In Russian). ______ * Corresponding author Karelin Roman D., Ph.D. (Engineering), A.A. Baykov Institute of Metallurgy and Materials Science of the Russian Academy of Sciences, 49 Leninsky ave., 119334, Moscow, Russian Federation Tel.: +7 916 590-42-76, e-mail: rdkarelin@gmail.com
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