Персона: 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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- ПубликацияТолько метаданныеEffect 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.
- ПубликацияОткрытый доступStructure and functional properties of rapidly quenched TiNiCu alloys with high copper contents(2021) Shelyakov, A. V.; Sitnikov, N. N.; Borodako, K. A.; Khabibullina, I. A.; Dyadechko, A. A.; Шеляков, Александр Васильевич; Ситников, Николай Николаевич; Бородако, Кирилл Анатольевич© Published under licence by IOP Publishing Ltd.Thin materials exhibiting the shape memory effect, with a narrow temperature hysteresis, are required to create miniature and high-speed devices. Quasi-binary intermetallic TiNi-TiCu alloys with high copper contents (more than 10 at %) demonstrate the reversible martensitic transformation with a small (4-6 K) hysteresis. Alloys of the TiNi-TiCu system with a copper content of 30-40 at.% were fabricated in an amorphous state by the planar flow casting technique at a melt cooling rate of106 K/s in the form of ribbons 30-50 μm thick. The alloy samples were subjected to dynamic crystallization using a single electric current pulse with duration of 5 ms. X-ray diffraction studies revealed almost fully martensitic state of the alloys with B19 structure at room temperature. TEM examination showed their structure to contain typical B19-martensite plates with a mean size of 20-80 nm. At the same time, the alloys exhibit a one-stage phase martensitic transformation B2↔B19 in the temperature range of (55 75) C, as well as pronounced shape memory effect, whose properties are largely determined by the structural parameters of the alloys.
- ПубликацияТолько метаданныеInvestigation 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
- ПубликацияТолько метаданныеFeatures of the Formation of the Crystalline Phase in Rapidly Quenched Amorphous Crystalline Ribbons of Ti50Ni25Cu25 Alloy Depending on Energy Input during Electropulse Treatment(2025) Sitnikov, N. N.; Greshnyakova, S. V.; Zaletova, I. A.; Shelyakov, A. V.; Ситников, Николай Николаевич; Шеляков, Александр Васильевич
- ПубликацияТолько метаданныеSpecifics in formation of nanolayer structure of coatings during their deposition using filtered cathodic vacuum arc deposition (FCVAD) technology(2019) Vereschaka, A.; Sitnikov, N.; Oganyan, G.; Sotova, C.; Ситников, Николай НиколаевичThe paper discusses the specific features of the formation of nanolayer structures of modifying coatings for metal-cutting tools using FCVAD technology. It is found that the nanolayer coating structure is affected both by the rotation speed of the turntable and by the speed of the planetary rotation of the tool set. It is found that the coating with the minimum thicknesses of nanolayers (about 4-6 nm) provides the longest tool life period. (C) 2019 Elsevier Ltd. All rights reserved.
- ПубликацияТолько метаданныеInvestigation of wear dynamics for cutting tools with multilayer composite nanostructured coatings in turning constructional steel(2019) Vereschaka, A.; Tabakov, V.; Grigoriev, S.; Oganyan, G.; Sitnikov, N.; Ситников, Николай Николаевич© 2018 Elsevier B.V. The paper deals with the wear dynamics shown by carbide tools with multilayer composite nanostructured coatings of various compositions. The investigation involved coatings based on nitrides of such metals as Ti, Zr, Cr, Nb, and Al with three-layer architecture, including adhesion, transition, and wear-resistant layers. The thickness of the coatings was about 4 µm. There was a series of cutting tests involving tools with the coatings under study in the turning of AISI 1045 steel at vc = 200, 250, 300, and 350 m/min. The comparative studies were conducted to investigate wear process patterns for tools with the coatings under study and for uncoated tools and tools with TiN reference coatings, depending on the cutting speed. In particular, the study considered the intensity and specific features of crater formation on the tool rake face. In particular, it was found that an increase in cutting speed led to more active movement of a crater away from the cutting edge, while at lower cutting speeds, a crater developed evenly. Diffusion and oxidation processes were registered and studied at the boundary between the coating and the material being machined. The use of the coatings under study makes it possible to significantly increase the cutting speed, while the optimal composition of the coating depends on the applied cutting speed.
- ПубликацияОткрытый доступCrystallization features of amorphous rapidly quenched high Cu content TiNiCu alloys upon severe plastic deformation(2019) Glezer, A.; Sundeev, R.; Khabibullina, I.; Sitnikov, N.; Shelyakov, A.; Ситников, Николай Николаевич; Шеляков, Александр Васильевич© 2019 by the authors.In recent years, the methods of severe plastic deformation and rapid melt quenching have proven to be an effective tool for the formation of the unique properties of materials. The effect of high-pressure torsion (HPT) on the structure of the amorphous alloys of the quasi-binary TiNi-TiCu system with a copper content of more than 30 at.% produced by melt spinning technique has been analyzed using the methods of scanning electron microscopy, X-ray diffraction analysis, and differential scanning calorimetry (DSC). The structure examinations have shown that the HPT of the alloys with a Cu content ranging from 30 to 40 at.% leads to nanocrystallization from the amorphous state. An increase in the degree of deformation leads to a substantial change in the character of the crystallization reflected by the DSC curves of the alloys under study. The alloys containing less than 34 at.% Cu exhibit crystallization peak splitting, whereas the alloys containing more than 34 at.% Cu exhibit a third peak at lower temperatures. The latter effect suggests the formation of regions of possible low-temperature crystallization. It has been established that the HPT causes a significant decrease in the thermal effect of crystallization upon heating of the alloys with a high copper content relative to that of the initial amorphous melt quenched state.
- ПубликацияТолько метаданныеInvestigation of multicomponent nanolayer coatings based on nitrides of Cr, Mo, Zr, Nb, and Al(2020) Grigoriev, S.; Vereschaka, A.; Milovich, F.; Tabakov, V.; Sitnikov, N.; Ситников, Николай Николаевич© 2020 Elsevier B.V.This paper presents the results of the investigations of multicomponent nanolayer coatings of Cr,Mo-(Cr,Mo,Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N, Cr,Mo-(Cr,Mo)N-(Cr,Mo,Al)N, and Zr,Nb-(Zr,Nb)N-(Zr,Nb,Al)N. The data on the microstructures and nanostructures of the coatings, including the hardness, phase composition, and chemical composition by coating thickness are presented. The research considers the differences in the phase composition of the coatings and reveals the difference in the wear process on the contact pads of the carbide inserts between the studied coatings and the wear patterns on the coatings from cutting workpieces made of 1045 steel. The multicomponent Cr,Mo-(Cr,Mo)N-(Cr,Mo,Zr,Nb,Al)N coating contains two cubic phases of (Cr,Mo,Al)N and (Zr,Nb,Al)N with the space group Fm3¯m. The Cr,Mo-(Cr,Mo)N-(Cr,Mo,Zr,Nb,Al)N coating exhibited the maximum hardness among the studied coatings, and a tool with such a coating demonstrated the longest lifetime. The coating is also characterized by higher resistance to brittle fracture and cracking.
- ПубликацияТолько метаданныеInvestigation of the properties of the Cr,Mo-(Cr,Mo,Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N multilayer composite multicomponent coating with nanostructured wear-resistant layer(2021) Grigoriev, S.; Vereschaka, A.; Milovich, F.; Andreev, N.; Sitnikov, N.; Ситников, Николай Николаевич© 2020 Elsevier B.V.The article discusses the properties of the Cr,Mo-(Cr,Mo,Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N multilayer composite multicomponent coating with a nanostructured wear-resistant layer. The structure and phase composition of the coating were investigated. The comparative cutting tests were carried out on carbide cutting tools with the coating under study and carbide cutting tools with the Ti–TiN-(Ti,Al,Cr)N commercial coating. Particular attention was paid to the study of the wear and fracture patterns typical for the coating and the diffusion processes on the “coating–material being machined” interface. The studies found the difference in the content of Fe in the coating nanolayers. In particular, the high content of Fe was detected in the nanolayers with the increased content of Cr–Mo, while the nanolayers with the increased content of Al demonstrated the low content of Fe. The depth of the Fe diffusion into the coating is 2–3 times lower compared to the Fe diffusion into a carbide substrate. The influence of the nanolayer structure of the coating on the crack propagation was considered. The studies revealed signs of plastic deformation in the surface layers of the coating. The investigation was also focused on the structure of a build-up of the material being machined with a layer structure demonstrating different levels of the oxidation inits layers.
- ПубликацияОткрытый доступОСОБЕННОСТИ КРИСТАЛЛИЗАЦИИ АМОРФНО-КРИСТАЛЛИЧЕСКОГО СПЛАВА TiNiCu(НИЯУ МИФИ, 2024) ХАЧАТРЯН, Д. А.; ШЕЛЯКОВ, А. В.; СИТНИКОВ, Н. Н.; Ситников, Николай Николаевич; Шеляков, Александр Васильевич; Хачатрян, Давид АрменовичАморфно-кристаллические слоистые ленты из сплава TiNiCu с эффектом памяти формы получены с помощью технологии быстрой закалки из жидкого состояния с разной толщиной кристаллического слоя. Исследовано влияние толщины кристаллического слоя на свойства сплавов, в частности, на процесс структурообразования при кристаллизации.