Персона: Столяров, Владимир Владимирович
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Институт физико-техничеcких интеллектуальных систем
Институт физико-технических интеллектуальных систем впервые в стране обеспечивает комплексную подготовку специалистов по созданию киберфизических устройств и систем самого различного назначения – основного вида технических устройств середины 21 века. ИФТИС реализует «дуальную» модель образования, в рамках которой направляет студентов на стажировку и выпускников для трудоустройства на передовые предприятия, занятые созданием инновационных киберфизических продуктов, в первую очередь, на предприятия ГК «Росатом». Основным индустриальным партнером ИФТИС является ведущее предприятие ГК «Росатом» — ФГУП «ВНИИА им. Н.Л. Духова».
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Владимир Владимирович
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- ПубликацияТолько метаданныеFriction and Wear of Al2O3 + G Nanocomposite Produced via Spark Plasma Sintering(2019) Klyatskina, E. A.; Stolyarov, V. V.; Столяров, Владимир Владимирович© 2019, Pleiades Publishing, Ltd.Abstract: We report the effect of graphene (G) allotropic carbon modification in a content range of 0.5–2.0 wt % on the tribological, strength, and structural characteristics of an Al2O3/G nanocomposite produced by a 10-min plasma spark sintering (at a pressure of 50 MPa and a temperature of 1550°C) of a nanopowder mixture, previously subjected to ultrasonic dispersion in organic solvent. Its lubricant free friction and wear are tested at room temperature on a tribometer under a load of 20 N, at a roundabout motion of a ruby ball penetrator on a disk. The nanohardness and elastic modulus of the nanocomposite are determined via kinetic indentation. The fracture surface structure and friction track are monitored using a scanning electron microscope. The microstructure in the bulk of the nanocomposite was probed via dark- and bright-field transmission electron microscopy scanning of thin foils. The thermal stability of graphene was monitored via Raman spectroscopy. The introduction of graphene is shown to improve micro- and nanohardness, elasticity, and wear resistance by two to three orders of magnitude, as well as to slightly decrease the coefficient of friction. A graphene content of 2 wt % alters the mechanism of wear from brittle fracture to viscous shear owing to stronger coupling of matrix grains and the presence of agglomerates. A lack of degradation and the retention of graphene thermal stability are evidenced as well. The morphology of graphene particles reveals their preferential arrangement inside the corundum grains rather than at the grain boundaries.
- ПубликацияТолько метаданныеMechanical Properties of VNS9-Sh TRIP Steel at Various Test Temperatures(2020) Terent'ev, V. F.; Frolova, A. V.; Sirotinkin, V. P.; Stolyarov, V. V.; Столяров, Владимир Владимирович© 2020, Pleiades Publishing, Ltd.Abstract: The influence of the test temperature from the range from +400 to –120°C on the mechanical properties and the phase composition of austenitic–martensitic VNS9-Sh TRIP sheet steel is studied. As the deformation temperature increases, the ultimate tensile strength is shown to decrease sharply from 1600 MPa at +20°C to 700 MPa at 400°C. A yield plateau disappears from static stress–strain curves beginning from a deformation temperature of 100°C. The strain-induced martensite content decreases from 84% at a deformation temperature of 20°C to 42% at 400°C. The strain-induced martensite content increases significantly during deformation in the temperature range from 0 to –120°C. The plasticity is maximal at –100°C: it decreases when the temperature decreases or increases.
- ПубликацияТолько метаданныеDielectric properties of nanocomposite ceramics Al2O3 / graphene processed by spark plasma sintering(2020) Sudzhanskaya, I. V.; Stolyarov, V. V.; Frolova, А. V.; Столяров, Владимир Владимирович© 2019 Elsevier Ltd and Techna Group S.r.l.Al2O3/graphene nanocomposites with graphene contents of 1 and 2 wt % were obtained by the SPS method and were characterized by means of electron microscopy and Raman spectroscopy. The aim of this work was to study the effect of graphene content on the temperature and frequency dependences of the electrical resistivity in nanocomposite ceramics. Using the impedance method with alternating current, the ceramic materials were studied over a wide temperature range, 23–530 °C and over a frequency range of 10−1 – 106 Hz. More than a half decrease in the porosity of the sintered composite with an increase in the graphene content was observed. Raman spectroscopy indicated the absence of graphene degradation during the SPS. The range of frequencies (100–103 Hz) and temperatures (23–130 °C) in which the dielectric can exhibit electron or ionic conductivity were determined.
- ПубликацияТолько метаданныеInfluence of strain rate and strain at temperature on TRIP effect in a metastable austenitic stainless steel(2020) Tilak, Kumar, J. V.; Sudha, J.; Padmanabhan, K. A.; Frolova, A. V.; Stolyarov, V. V.; Столяров, Владимир Владимирович© 2020 Elsevier B.V.Metastable TRIP (TRansformation-Induced Plasticity) steel strips with a microstructure comprising ferrite, retained austenite and martensite were subjected to tensile tests at different strain rates of 10−5s−1, 10−4s−1, 10−3s−1 and temperatures 27 °C, 50 °C and 100 °C. The TRIP steel specimens exhibited very high tensile strengths (up to ~1700 MPa) in tests carried out at room temperature, which is attributed to the TRIP effect. Thermal stability of the phases present in the TRIP steel in the as-received condition was assessed by in-situ high temperature XRD and DSC (Differential Scanning Calorimetry) analysis to determine the retained austenite decomposition temperature. Microstructural analysis by XRD, optical microscopy and electron microscopy was used before and after the tensile tests to identify the features present at micro- and nano-scales, which are responsible for the observed mechanical properties. Macrographs taken from the surface of the specimens after the tensile tests showed the presence of Lüders bands and their occurrence was concurrent with the TRIP effect. The effect of strain rate and temperature on the TRIP effect and the associated mechanical response are discussed in detail.
- ПубликацияТолько метаданныеTemperature-dependence of the TRIP effect in a metastable austenitic stainless steel(2019) Padmanabhan, K. A.; Terentyev, V. F.; Stolyarov, V. V.; Столяров, Владимир ВладимировичThe effect of test temperature in the range 20 - 400 degrees C on mechanical properties under quasi-static tension and phase composition in metastable austenite-martensite TRIP steel in the form of a sheet of 0.3 mm thickness is investigated. Here strength and ductility increases are caused by austenite to martensite phase transformation. As supplied, the steel contained 65% martensite and 35% austenite. Due to tensile testing at room temperature, the amount of martensite increases to 84%, which leads to high strength (1600 MPa) and a relative elongation to failure of 20%. There is no neck formation. With an increase in test temperature from room temperature to 400 degrees C, the strength characteristics, especially yield strength, sharply decreases to 700 MPa and below. At the same time, the elongation to failure decreases by an order of magnitude to 2%. Above a test temperature of 100 degrees C, deformation localization begins, the length of the yield plateau on the stress-strain curve decreases, and then disappears. X-ray structural analysis of the sample surface after tension showed that the volume fraction of martensite in the microstructure decreases from 84% at 20 degrees C to 42% at 400 degrees C. With an increase in temperature in the range of 20 - 400 degrees C the influence of the TRIP effect on the mechanical properties of austenitic steel gradually decreases, and the direct transformation of austenite to martensite eventually changes to the reverse transformation of martensite to austenite. It is assumed that the embrittlement of steel with increasing temperature is associated with inhomogeneous martensite decomposition and precipitation of fine carbides at grain boundaries.
- ПубликацияОткрытый доступAcousto-and electroplastic effects in alloy with reversible martensitic transformation(2019) Tsarenko, Y. V.; Rubanik, V. V.; Rubanik, V. V.; Frolova, A. V.; Stolyarov, V. V.; Столяров, Владимир Владимирович© Published under licence by IOP Publishing Ltd. The article discusses the deformation behaviour of T1 49.3 Ni 50.7 alloy in the austenitic state during tensile tests under pulsed current and ultrasound at ambient temperature and 200 °C. The stress jumps from a combination of ultrasound and / or single pulse current are analyzed. The direction and magnitude of stress jumps are determined by the phase state of the material, the degree of deformation and the presence of electroplastic (EPE) and acoustoplastic (APE) effects. The different direction of the stress jumps in this shape memory alloy is related to the position of the deformation temperature relative to the deformation martensite formation temperature.
- ПубликацияТолько метаданныеElectroconductivity of Al2O3/graphene nanocomposite processed by SPS technique(2019) Sanchez-Bolinchez, A.; Klyatskina, E.; Segovia-Lopez, F.; Zholnin, A. G.; Stolyarov, V. V.; Столяров, Владимир Владимирович© 2019 IOP Publishing Ltd. All rights reserved.Electrical conductivity (σ), relative dielectric permittivity (ϵr) and dissipation factor (D) measured in graphene-alumina composites. Samples obtained by plasma spark sintering (SPS) from a mixture of raw powders: δ-alumina (36 nm average particle size) and graphene flakes (3 nm thickness and 2-3 μm length). Graphene content in samples was 0, 1 and 2% by weight. The study carried out for frequencies from 50 Hz to 100 kHz. Both c and ϵr were higher for Al2O3-2% graphene: up to 90 μS/m and 19 respectively; while alumina with 1% graphene showed similar values to the pure alumina samples: 50 μS/m to electrical conductivity and 16 to relative permittivity. The dissipation factor was similar in the three materials tested. D increased with the frequency, reaching high values (0.7) at 100 kHz. Composites with 1 and 2% graphene content showed a dissimilar dielectric behavior with the frequency. Alumina reflected a classical behavior of the permittivity dependence with the frequency. Graphene composites also show the same behavior at frequencies above 100 Hz. Below this frequency, the presence of graphene increases the relative permittivity to exceed that from pure alumina. The graphene content leads to rise of relative permittivity, which means easier polarizability.
- ПубликацияТолько метаданныеDeformation and current interaction in nanostructured and amorphous Ti based alloys(2019) Stolyarov, V. V.; Столяров, Владимир Владимирович© Published under licence by IOP Publishing Ltd.The deformation behavior under tension and pulse current in course-grained, nanostructured and amorphous titanium based alloys is investigated. The influence of grain size, structure state and current mode on shape memory effect and electroplastic effect has been shown. Structure refinement up to nanosize area, occurrence of interphase boundaries, and amorphous state in alloys suppress the electroplastic effect. In TiNi alloys with phase thermoelastic transformation induced by deformation or temperature, current pulses decreases stress jumps downwards induced by manifestation of the electroplastic effect and increases stress jumps upwards connected with the shape memory effect.
- ПубликацияТолько метаданныеEvolution of Physical and Mechanical Properties of Nanostructured Titanium upon Annealing(2019) Stolyarov, V. V.; Столяров, Владимир Владимирович© 2019, Allerton Press, Inc.Abstract: Nanocrystalline and submicrocrystalline titanium are synthesized using the methods of severe plastic deformation by twisting and equal channel angular pressing with subsequent cold rolling. The microhardness, magnetic susceptibility, and electrical resistivity have maximum values in highly strained titanium. Annealing in the temperature range of 673–1123 K leads to restoration and recrystallization manifested in decreases in the microhardness by a factor of 2, in the magnetic susceptibility by 15%, and in the resistivity by 20%.
- ПубликацияТолько метаданныеOn the tensile behaviour of coarse and ultrafine grained NiTi(2019) Kumar, JVT.; Jayaprakasam, S.; Padmanabhan, K. A.; Misochenko, A. A.; Stolyarov, V. V.; Столяров, Владимир ВладимировичNi50.7Ti49.3 alloy of coarse grained (CG) and ultrafine grained (UFG) microstructures were subjected to tensile tests at different strain rates of 10(-1) s(-1), 10(-2) s(-1), 10(-3) s(-1) and temperatures of 25 degrees C, 50 degrees C and 200 degrees C. The CG state was attained by quenching and the UFG state by electroplastic rolling (EPR). Transmission electron microscopy of the UFG Ni50.7Ti49.3 alloy revealed the presence of shear bands and sub -grains. The microstructure after tensile testing revealed the presence of grains and twin planes of the B19' martensite phase, which indicates that twinning also plays a role in the deformation of the alloy, in addition to crystallographic slip. The effects of grain size, strain rate and temperature on the stress-induced martensite transformation present during the tensile tests are discussed. Serrated flow was observed intermittently in the stress-strain curves of both CG and UFG Ni50.7Ti49.3 alloy for some specific combinations of strain rate and temperature. Serrations observed were not limited to the stress plateau region, which is typically seen in the stress-strain curves of NiTi alloys as a result of phase transformation, but were noticed rather randomly through the entire strain range. This unsteady flow behaviour is also discussed.