Персона: Шеляков, Александр Васильевич
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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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- ПубликацияОткрытый доступRecoverable strain induced by martensitic transformation during holding of NiTi-based shape memory alloys under constant stress and temperature(2023) Belyaev, S.; Resnina, N.; Demidova, E.; Shelyakov, A.; Шеляков, Александр Васильевич
- 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.
- ПубликацияОткрытый доступ3D Nanomanipulation: Design and applications of functional nanostructured bio-materials(2020) Lega, P. V.; Orlov, A. P.; Frolov, A. V.; Subramani, R.; Shelyakov, A. V.; Шеляков, Александр Васильевич© 2020 IOP Publishing Ltd.Recent progress in the development of the new functional materials opens up exciting possibilities for designing reconfigurable micro- and nano-structures and for operating mechanical nanotools which are controlled by external fields or heat. The nanotools such as nanotweezers with an active layer thickness of about several tenths of nm, and whose overall size is of the order of 1 μm can be applied to different micro- and nanoobjects. The present report gives an overview of the application of mechanical nanotools in 3D nanomanipulation of bio-nano objects such as micro biofibers DNA etc. The future prospects of mechanical bottom up nanomanipulation for biomedical technology, food technology are discussed.
- ПубликацияОткрытый доступFormation of structure of TiNiCu alloys with high copper content upon producing by planar flow casting(2020) Shelyakov, A. V.; Sevryukov, O. N.; Sitnikov, N. N.; Borodako, K. A.; Khabibullina, I. A.; Шеляков, Александр Васильевич; Севрюков, Олег Николаевич; Ситников, Николай Николаевич; Бородако, Кирилл Анатольевич© Published under licence by IOP Publishing Ltd.The rapidly quenched alloys of the quasibinary intermetallic TiNi-TiCu system with a high copper content (more than 25 at.%) are of great interest as shape memory materials due to the possibility of a significant decrease in the temperature and deformation hysteresis in comparison with the binary TiNi alloy. To obtain alloys with a copper content of 25 to 40 at.%, the planar flow casting technique was used. The alloys were fabricated at a melt cooling rate of about 106 K/s in the form of ribbons 30-50 µm thick and wide in the range from 7 to 20 mm. The study of the structure of the alloys was carried out using X-ray diffraction analysis, scanning and transmission electron microscopy. It was shown that from the ribbon side, contacting the quenching wheel, all alloys are amorphous, while on the non-contact side of the ribbons of alloys with 25 and 30 at.% Cu, a thin surface crystalline layer with a B2 structure is observed. Using energy dispersive X-ray spectroscopy, it was found that the content of the alloy components in the amorphous and crystalline phases coincides.
- ПубликацияОткрытый доступInhomogeneity and anisotropy in nanostructured melt-spun ti2 nicu shape-memory ribbons(2020) Bhale, P.; Ari-Gur, P.; Koledov, V.; Shelyakov, A.; Шеляков, Александр Васильевич© 2020 by the authors. Licensee MDPI, Basel, Switzerland.Ti2 NiCu exhibits outstanding properties, such as superelasticity. Recently, its functional properties were also demonstrated on the nanoscale, a fact that makes it the preferred choice for numerous applications. Its properties strongly depend on the manufacturing route. In this work, phase analysis, inhomogeneity, and texture of melt-spun Ti2 NiCu ribbons were investigated using X-ray diffraction. Initially, the ribbons are amorphous. Passing an electric current result in controlled crystallization. Ribbons with 0%, 60%, and 96% crystallinity were studied. Both B2 austenite and B19 martensite phases were observed. Using grazing incidence X-ray diffraction, the inhomogeneity across the thickness was investigated and found to be substantial. At the free surface, a small presence of titanium dioxide may be present. Pole figures of 60% and 96% crystallinity revealed mostly strong fiber <100>B2 texture in the thickness direction. These observations may be inferred from the manufacturing route. This texture is beneficial. The inhomogeneity across the thickness has to be considered when designing devices.
- ПубликацияОткрытый доступApplication of laser radiation for creation of metamaterial based on rapidly quenched shape memory TiNiCu alloy(2020) Sitnikov, N. N.; Irzhak, A. V.; Tabachkova, N. Yu.; Koledov, V. V.; Borodako, K. A.; Shelyakov, A. V.; Ivanov, A. A.; Бородако, Кирилл Анатольевич; Шеляков, Александр Васильевич; Иванов, Андрей Анатольевич© 2020 IOP Publishing Ltd.The work deals with application of laser radiation for creation of metamaterial - layered structural composite based on rapidly quenched TiNiCu thin ribbon. Structural properties of the composite were examined by transmission and scanning electron microscopy. Considerable two-way shape memory effect was achieved and studied.
- ПубликацияОткрытый доступInvestigation of thermal-structural characteristics at two-way shape memory effect of rapid quenched laminated amorphous-crystalline ribbons of Ti50Ni25Cu25alloy(2020) Sivtsova, G. V.; Khabibullina, I. A.; Sitnikov, N. N.; Shelyakov, A. V.; Ситников, Николай Николаевич; Шеляков, Александр Васильевич© Published under licence by IOP Publishing Ltd.The work is devoted to the study of processes of structural changes leading to the realization of the two-way shape memory effect (TWSME) in the rapid quenched amorphous-crystalline alloy Ti50Ni25Cu25. The object of the study was a rapid quenched laminated amorphous-crystalline Ti50Ni25Cu25 alloy ribbon with a thickness of about 39 um and with a thickness of surface crystal layer about 10 µm was present on the non-contact side relative to the quenching wheel. In the ribbon under study, without any additional heat treatments the TWSME with bending deformation from a rectilinear shape during heating and cooling in the range of martensitic transformation is manifested. The samples were characterized by means: scanning and transmission electron microscopy; X-ray diffraction analysis; differential scanning calorimetry; measuring the characteristics of the crystalline layer during the implementation of TWSME and the temperature dependence of the form change. It was shown that the formation of a laminated amorphous-crystalline composite occurs due to the martensitic transformation of B2~B19 in the crystal layer and the accompanying TWSME as a result of which the crystal layer is reduced.
- 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.
- ПубликацияОткрытый доступInvestigation of the effect of electric pulse heat treatment of rapid-quenched Ti50Ni25Cu25 alloy ribbons with a thin surface crystal layer on the structure formation from an amorphous state(2020) Khabibullina, I. A.; Mashchenko, V. I.; Sivtsova, G. V.; Sitnikov, N. N.; Shelyakov, A. V.; Ситников, Николай Николаевич; Шеляков, Александр Васильевич© Published under licence by IOP Publishing Ltd.This work is devoted to the study of the influence of electric pulse heat treatment of rapid-quenched Ti50Ni25Cu25 alloy ribbons (at. %) with a surface crystal layer. The object of the study was a rapid-quenched layered amorphous-crystal ribbon with a thickness of about 30 GMSH. A three-dimensional finite element mesh generator with built-in pre-and post-processing facilities. http://gmsh.info/m and a width of about 1.5 mm, in which a thin surface crystal layer (2.5 μm) was present on the non-contact side relative to the quenching wheel. The alloy samples were subjected to electric pulse treatment by passing a single pulse of electric current through the sample with a variable duration. For comparison, samples of the alloy were obtained, crystallized by standard isothermal heat treatment. The samples were characterized by means of scanning electron microscopy techniques, energy dispersive X-ray analysis and differential scanning calorimetry. It was shown that electric pulse treatment with an exposure time of less than 1 second leads to a significant change in the formed crystalline structure in comparison with the structure obtained by isothermal treatment. The microstructure of such samples in cross section is characterized by an uneven distribution of crystals over the thickness of the ribbon: columnar crystals are observed from the contact and non-contact sides of the ribbon, and large crystals are present in the inner part of the ribbon.
- ПубликацияОткрытый доступStudy of Structure and Phase Transformations in Rejuvenated Rapidly Quenched TiNiCu Alloys(2023) Shelyakov, A.; Sitnikov, N.; Zaletova, I.; Borodako, K.; Шеляков, Александр Васильевич; Ситников, Николай Николаевич; Бородако, Кирилл АнатольевичAlloys of the quasibinary TiNi-TiCu system manufactured by melt quenching in the form of thin 20–50 Ојm ribbons have proven to show good potential as materials for the fabrication of micromechanical devices. At high cooling rates (about 106 K/s), this method allows producing high-copper (more than 20 at.%) amorphous alloys which exhibit an excellent shape-memory effect after crystallization. Their properties are known to largely depend on the crystallization conditions and the structure of the initial amorphous material acting as a precursor for the formation of crystal phases. It has been shown recently that the rejuvenation procedure (cryogenic thermocycling) of metallic glasses is one of the most promising methods of improving their properties. In this study, we investigated for the first time the effect of cryogenic thermocycling of rapidly quenched amorphous TiNiCu on the initial state, as well as on structure formation and the phase transformation patterns of subsequent crystallization conducted using various methods. The effect was analyzed utilizing the methods of scanning and transmission electron microscopy, X-ray diffraction analysis, and differential scanning calorimetry. The results show that rejuvenation treatment slightly reduces the glass transition and crystallization onset temperatures and moderately changes the sizes of structural features (grains, martensite plates), the quantity of the martensite phase, and the characteristic temperatures and enthalpy of the martensitic transformation.