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Ситников, Николай Николаевич

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Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Николай Николаевич

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Только метаданные
Investigation of the wear pattern of the Ti-TiN-(Ti,Al,Cr)N nanostructured coating with a varying modulation period
(2023) Grigoriev, S.; Vereschaka, A.; Milovich, F.; Sitnikov, N.; Ситников, Николай Николаевич
Только метаданные
Investigation of tribological and functional properties of Cr,Mo-(Cr,Mo)N-(Cr,Mo,Al)N multilayer composite coating
(2021) Vereschaka, A.; Grigoriev, S.; Milovich, F.; Migranov, M.; Sitnikov, N.; Ситников, Николай Николаевич
© 2020 Elsevier LtdThe article describes the investigation of the properties of the Cr,Mo-(Cr,Mo)N-(Cr,Mo,Al)N multilayer composite coating. For the coated sample, the adhesion component fadh of the coefficient of friction increases almost linearly with an increase in temperature from 500 to 700 °C. Then, with a further rise in temperature up to 800 °C, the growth of fadh slows down significantly, and when the temperature rises from 800 to 1000 °C, fadh begins to decrease noticeably. The studies deal with the cutting properties of carbide tools with the coating under study during the cutting of corrosion-resistant AISI 321 at various cutting speeds. The wear pattern on the coating during the cutting was considered. An diffusion layer with the thickness of 20–40 nm was detected during the studies of the elemental and phase compositions in the region of the “tool material–coating” interface. In this layer, the studies revealed the active diffusion of Fe and other steel components into the coating, as well as the diffusion of Mo from the coating into the material being machined in combination with oxidation processes. It was found that during the cutting with the coated tool, the thickness of the diffusion layer was 10–15 times lower compared to that in the uncoated tool. While a certain content of oxygen is detected in the layers on the coating surface, no active formation of the oxides of Al2O3, MoO3, and Cr2O3 was revealed, and the formation of a noticeable amount of Fe2O3 was found in the layers of the material being machined adjacent to the coating surface.
Только метаданные
Influence of copper content and thermal treatment on shape memory effect in rapidly quenched TiNiCu alloys
(2021) Borodako, K. A.; Shelyakov, A. V.; Sitnikov, N. N.; Zaletova, I. A.; Sevryukov, O. N.; Бородако, Кирилл Анатольевич; Шеляков, Александр Васильевич; Ситников, Николай Николаевич; Севрюков, Олег Николаевич
© 2021 Institute of Physics Publishing. All rights reserved.Amorphous alloys of the TiNi - TiCu system with a copper content of 25 to 40 at.% were prepared by planar flow casting at a melt cooling rate of 106 K/s. Crystallization of the alloys was carried out by isothermal annealing and by action of single electric pulse with a duration of 5 ms. Shape memory behavior and structure of the alloys was investigated by means of bending tests and X-ray phase analysis. It was found that increasing the copper content to above 30 at.% considerably reduces the plasticity and shape memory effect of the alloys. However, abrupt decreasing the annealing duration significantly improves the shape memory performance due to prevention of the formation of brittle Ti-Cu phases in the alloys structure.
Только метаданные
Study of the Structure, Phase Transformations, and Shape Memory Effect in Amorphous-Crystalline TiNiCu Alloy
(2025) Shelyakov, A. V.; Sitnikov, N. N.; Khachatrian, D. A.; Zaletova, I. A.; Шеляков, Александр Васильевич; Ситников, Николай Николаевич; Хачатрян, Давид Арменович
Только метаданные
Two-Way Shape Memory Effect in Rapidly-Quenched High-Copper TiNiCu Alloys Deformed in the Martensitic State
(2020) Shelyakov, A. V.; Sitnikov, N. N.; Borodako, K. A.; Sevryukov, O. N.; Шеляков, Александр Васильевич; Ситников, Николай Николаевич; Бородако, Кирилл Анатольевич; Севрюков, Олег Николаевич
© 2020, Pleiades Publishing, Ltd.Abstract: The effect of martensitic deformation on the two-way shape-memory effect (SME) of quasi-binary high-copper TiNi–TiCu alloys (with 25–40 at % Cu) is studied. The alloys are prepared by rapid quenching from the melt in an amorphous state in the form of ribbons 30–50 μm in thickness. The alloys crystallize during isothermal annealing, the time of which is varied from 100 to 300 s, and during a single current pulse 10 ms in duration. The relatively low bending strains (1.5–3%) are shown to cause two-way SME in TiNiCu alloys; as the strain of martensite increases, the reversible strain in the martensitic transformation range increases markedly. An increase in the copper content is found to cause a substantial decrease in the value of two-way SME, which is related to the formation of the brittle TiCu phase. At the same time, a decrease in the heat treatment time causes an increase in the reversible strain, which reaches the maximum value (2.35%) for the alloy with 25 at % Cu subjected to high-rate electric pulse treatment.
Только метаданные
Properties of (Cr,Al,Si)N-(DLC-Si) composite coatings deposited on a cutting ceramic substrate
(2020) Grigoriev, S. N.; Volosova, M. A.; Vereschaka, A. A.; Milovich, F.; Sitnikov, N. N.; Ситников, Николай Николаевич
© 2020 Elsevier Ltd and Techna Group S.r.l.The article discusses the specific features of the deposition of (Cr,Al,Si)N-(DLC-Si) composite coatings on the (Al2O3 + TiC) ceramic substrate and studies the performance properties of ceramic cutting tools with the above coatings. Three coating options were considered, including a (Cr,Al,Si)N transition layer and a DLC-Si wear-resistant layer with various options of Si content. The coating structure was investigated using scanning electron microscopy, transmission electron microscopy (TEM), and high-resolution TEM. The crystalline structures of the coatings were studied using the selected-area diffraction pattern. The studies substantiated the need for the application of a (Cr,Al,Si)N transition layer between a ceramic substrate and the DLC-Si coating, and the influence of the Si content on the coating properties was also considered. The cutting properties of tools with the DLC-Si coatings of various structures were studied during the turning of AISI 52100 (HRC 56-58) hardened steel. The studies also focused on the wear pattern of uncoated tools and tools with the studied coatings. The application of the (Cr,Al,Si)N-(DLC-Si) coating changes the wear pattern and can prolong the life of a ceramic cutting tool.
Только метаданные
Influence of the Nanostructure Parameters of Wear-Resistant Coatings on the Properties of Carbide Tools
(2022) Vereschaka, A.; Volosova, M.; Milovich, F.; Andreev, N.; Sitnikov, N.; Ситников, Николай Николаевич
© 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.The article deals with the properties of the Ti-TiN-(Ti,Cr,Al)N multilayer composite coatings with a nanolayer structure of their wear-resistant layers and the nanolayer period λ within a range from 10 to 900 nm. The studies were focused on the coating nanostructures and the influence of the nanolayer period λ on the performance properties of coated cutting tools during the turning of American Iron and Steel Institute (AISI) 420 (230 HB) martensitic stainless steel. The investigation found that the coatings with the nanolayer period λ = 10–25 nm demonstrated the best resistance to the crater formation on the rake face of cutting tools and to flank wear. The highest wear resistance was demonstrated by a coated tool with the nanolayer period λ = 10 nm.
Только метаданные
Effect of Electric Pulse Treatment under Tensile Stress on the Properties of Rapidly Quenched Ti50Ni20Cu30 Alloy
(2021) Shelyakov, A. V.; Sitnikov, N. N.; Zaletova, I. A.; Borodako, K. A.; Шеляков, Александр Васильевич; Ситников, Николай Николаевич; Бородако, Кирилл Анатольевич
© 2021, Allerton Press, Inc.Abstract: Amorphous ribbons from a rapidly quenched alloy of the TiNi–TiCu quasi-binary system with copper content of 30 at % are crystallized via electric pulse treatment with variable durations of impact in the range of 1 to 100 ms at external tensile stress of up to 250 MPa. It is shown that the formed bimorph structure of columnar and coarse crystals is characterized by considerable differences when compared to a rapidly quenched alloy with 25 at % copper. An increase in tensile stress does not affect the phase composition or microstructure of the alloy, but it does lower the critical temperatures of martensitic transformation.
Только метаданные
Effect of high-pressure torsion on the structure and properties of the natural layered amorphous-crystalline Ti2NiCu composite
(2020) Sundeev, R. V.; Shalimova, A. V.; Chernogorova, O. P.; Glezer, A. M.; Sitnikov, N. N.; Shelyakov, A. V.; Ситников, Николай Николаевич; Шеляков, Александр Васильевич
© 2020 Elsevier B.V.The room-temperature high-pressure torsion (HPT) behavior of a natural layered amorphous-crystalline composite with the precursor phases of the same chemical composition, but differing in structure has been studied by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and the measurements of indentation hardness (HIT) and indentation modulus (EIT) over the cross section of the samples. The force deformation parameters (torsion moment) realized upon HPT of the Ti2NiCu samples tested in three initial structural states (amorphous, crystalline, and composite) have been traced in situ with a special facility. Three different regions of amorphous, crystalline, and transitional structures are distinguished in the composite. It is shown that two different deformation mechanisms are simultaneously realized in crystalline and amorphous regions of the composite upon HPT. An attempt was made to identify the role of the transition layer upon deformation of the composite.
Только метаданные
Effect of high-rate annealing on microstructure, martensitic transformation and shape memory behavior of TiNiCu melt-spun ribbons
(2019) Khabibullina, I.; Tabachkova, N.; Andreev, N.; Shelyakov, A.; Sitnikov, N.; Fominski, V.; Шеляков, Александр Васильевич; Ситников, Николай Николаевич; Фоминский, Вячеслав Юрьевич
© 2019 Elsevier B.V. The amorphous rapidly quenched quasi-binary TiNi–TiCu alloys containing 30–38 at.% Cu were crystallized by isothermal annealing at 500 °C for 300 s and by exposing to short electric pulse with a duration of 10 ms to study the effect of the annealing rate on their properties. The results obtained showed that electropulse crystallization fundamentally changed the microstructure of the alloys due to almost completely hindering the formation of brittle Ti-Cu phases. This leads to a significant increase in the enthalpy of the martensitic transformation and a considerable shift of the transformation range towards higher temperatures. It was found that reducing the crystallization time dramatically increases the plasticity and shape memory effect of the alloys.