OBRABOTKAMETALLOV Vol. 28 No. 3 2026 328 MATERIAL SCIENCE References 1. Reed R.C. The superalloys: fundamentals and applications. Cambridge, Cambridge University Press, 2008. 388 p. ISBN 978-1-139-45863-4. Eff ect of direct laser deposition process parameters on the microstructure and mechanical properties of new nickel-base superalloys based on ZhS6K Ilya Astakhov a, *, Sofi a Korchmarchik b, Margarita Klimova c, Grigoriy Zadykyan d, Rudolf Korsmik e, Nikita Stepanov f Institute of Laser and Welding Technologies, Saint Petersburg State Marine Technical University, 3 Lotsmanskaya str., Saint Petersburg, 190121, Russian Federation a https://orcid.org/0009-0008-5409-9997, Astakhov@smtu.ru; b https://orcid.org/0009-0003-7716-146X, happy23sofi a@gmail.com; c https://orcid.org/0000-0002-2188-0209, M.V.klimova@ilwt.smtu.ru; d https://orcid.org/0000-0001-7942-2799, gzadykyan@mail.ru; e https://orcid.org/0000-0003-1591-1942, Rudak27@yandex.ru; f https://orcid.org/0000-0003-2476-3953, stepanov@corp.smtu.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. 315–330 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2026-28.3-315-330 ART I CLE I NFO Article history: Received: 15 July 2026 Revised: 18 July 2026 Accepted: 14 August 2026 Available online: 15 September 2026 Keywords: Ni-based superalloys Additive manufacturing Technological parameters Microstructure Mechanical properties Funding This research was funded by the Russian Science Foundation, grant no. 23-19-00622-P. ABSTRACT Introduction. Nickel-base superalloys are indispensable materials for hot-section components of gas turbine engines (GTE); however, traditional manufacturing of geometrically complex parts is highly time- and resourceconsuming. The adoption of additive manufacturing (AM), in particular direct laser deposition (DLD), enables high-precision fabrication of free-form components. Nevertheless, most nickel-base superalloys with a high volume fraction of the γ′ phase (Ni3Al) are prone to cracking. A promising approach is the development of new alloy compositions specially adapted for AM. The purpose of this study is to investigate Investigation of the infl uence of DLD parameters on cracking behavior, microstructure, and mechanical properties of the previously designed Ni68 and Ni75 alloys based on the ZhS6K superalloy. Materials and methods. Thin-walled specimens were produced by DLD with varying laser power, scanning speed, laser spot diameter, and deposition strategy. Cracking susceptibility was evaluated by the specifi c crack length. Porosity, microstructure, and phase composition were analyzed by optical and scanning electron microscopy. Mechanical properties were assessed by microhardness measurements. Results and discussion. A non-linear dependence of the specifi c crack length on laser power was revealed, with a maximum at 700 W for small spot diameters. The bidirectional deposition strategy was shown to reduce cracking compared with the unidirectional strategy. For the Ni75 alloy, optimum parameters (power 300 W, speed 3 mm/s, spot diameter 1.0–1.5 mm) under the bidirectional strategy were identifi ed, yielding defect-free specimens with a porosity below 0.2%. It was established that the lower carbon content in Ni75 suppresses carbide precipitation, thus reducing the cracking probability. Increasing the laser power from 300 to 1500 W only weakly aff ects the transverse grain size, but induces a transition from a near-equiaxed morphology to a columnar one with a pronounced <100> texture; the volume fraction of the strengthening γ′ phase remains constant at ~60% for Ni68 and ~41% for Ni75. Microhardness exhibits a weak dependence on the deposition parameters: 390–410 HV for Ni75 and 430–450 HV for Ni68, indicating the predominant contribution of the γ′ phase characteristics. The obtained results demonstrate the applicability of the developed alloys for the additive manufacturing of thin-walled high-temperature components. For citation: Astakhov I.I., Korchmarchik S.O., Klimova M.V., Zadykyan G., Korsmik R., Stepanov N.D. Eff ect of direct laser deposition process parameters on the microstructure and mechanical properties of new nickel-base superalloys based on ZhS6K. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2026, vol. 28, no. 3, pp. 315–330. DOI: 10.17212/19946309-2026-28.3-315-330. (In Russian). ______ * Corresponding author Astakhov Ilya Ivanovich, Engineer Institute of Laser and Welding Technologies, Saint Petersburg State Marine Technical University, 3 Lotsmanskaya str., 190121, Saint Petersburg, Russian Federation Тел.: +7 930 087-99-93, e-mail: Astakhov@smtu.ru
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