OBRABOTKAMETALLOV Vol. 27 No. 4 2025 269 MATERIAL SCIENCE Eff ect of laser radiation wavelength on the structure and functional properties of TiNi alloy during UV laser treatment Tatyana Sablina a, *, Marina Kandaurova b, Ilya Zyatikov c , Yurii Panchenko d Institute of High Current Electronics of the Siberian Branch of the RussianAcademy of Sciences, 2/3AkademicheskyAvenue, Tomsk, 634055, Russian Federation а https://orcid.org/0000-0002-5941-5732, sabltat@mail.ru; b https://orcid.org/0000-0003-0236-2227, panchenko.marina4@gmail.com; c https://orcid.org/0000-0003-3219-9299, zyatikov@lgl.hcei.tsc.ru; d https://orcid.org/0000-0001-8017-7268, yu.n.panchenko@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. 2025 vol. 27 no. 4 pp. 257–271 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2025-27.4-257-271 ART I CLE I NFO Article history: Received: 08 October 2025 Revised: 17 October 2025 Accepted: 31 October 2025 Available online: 15 December 2025 Keywords: Ultraviolet laser radiation Radiation wavelength Surface modifi cation Laser treatment Wettability TiNi alloy Funding This research was carried out with support from the Russian Science Foundation grant No. 25-79-31008, https://rscf.ru/project/25-79-31008/. ABSTRACT Introduction. The widespread use of TiNi-based functional alloys in medicine requires targeted management of their surface properties, such as wettability and biocompatibility. One of the promising methods for surface modifi cation is laser treatment, especially in the UV range of the spectrum. The effi ciency of UV laser treatment is due to the high photon energy, strong absorption by metals, and the shallow depth of the thermal eff ect zone. The purpose of this work is to investigate the eff ect of UV laser radiation wavelength (266 and 355 nm) on the structural and phase state, chemical composition, and wettability of the TiNi alloy surface, with the goal of subsequently controlling the material’s functional properties. Materials and research methods. TiNi surface modifi cation was performed using a pulsed Nd:YAG laser operating at wavelengths of 266 and 355 nm in ambient air. The modifi ed surfaces were analyzed by scanning electron microscopy with energy-dispersive spectroscopy (SEMEDS). Microstructure, elemental composition, and phase composition were analyzed by X-ray diff raction (XRD). Wettability was estimated using the sessile drop method. The free surface energy, along with its dispersive and polar components, was then calculated from the contact angle data using the OWRK method. Results and discussion. UV laser treatment, varying parameters such as laser radiation wavelength and scanning speed, was found to induce changes in the morphology, elemental composition, phase composition of the surface layer of TiNi alloy samples, and their surface properties. Following UV laser treatment at wavelengths of 266 and 355 nm and low scanning speeds (V = 200 and 500 μm/s), single microcracks or microcrack networks resulting from thermal exposure were observed on the specimen surfaces. The oxygen content on the TiNi surface increased by a factor of 5 to 18 compared to the initial state after UV laser treatment. Furthermore, the phase composition of the TiNi alloy underwent noticeable changes, with titanium oxide phases being detected on the surface after laser exposure. The higher-energy photons (λ = 266 nm) resulted in a more pronounced change in the surface morphology and properties of TiNi compared to the 355 nm radiation under identical treating conditions. UV laser treatment signifi cantly increased the surface hydrophilicity: the contact angle decreased from ≈75° in the initial state to ≈25° and ≈11° after treatment with 355 and 266 nm radiation wavelength, respectively. Additionally, an increase in the free surface energy of the TiNi specimens was observed, primarily due to a signifi cant increase in the polar component. For citation: Sablina T.Y., Kandaurova M.Yu., Zyatikov I.A., Panchenko Yu.N. Eff ect of laser radiation wavelength on the structure and functional properties of TiNi alloy during UV laser treatment. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2025, vol. 27, no. 4, pp. 257–271. DOI: 10.17212/1994-6309-2025-27.4-257-271. (In Russian). ______ * Corresponding author Sablina Tatyana Yu., Ph.D. (Engineering), Scientifi c associate Institute of High Current Electronics of the Siberian Branch of the Russian Academy of Sciences, 2/3 Akademichesky Avenue, 634055, Tomsk, Russian Federation Tel.: +7 913 843-21-78, e-mail: sabltat@mail.ru References 1. Jani J.M., Leary M., Subic A., Gibson M.A. A review of shape memory alloy research, applications and opportunities. Materials & Design, 2014, vol. 56, pp. 1078–1113. DOI: 10.1016/j.matdes.2013.11.084. 2. Elahinia M., Moghaddam N.S., Andani M.T., Amerinatanzi A., Bimber B.A., Hamilton R.F. Fabrication of NiTi through additive manufacturing: A review. Progress in Materials Science, 2016, vol. 83, pp. 630–663. DOI: 10.1016/j.pmatsci.2016.08.001.
RkJQdWJsaXNoZXIy MTk0ODM1