Персона: Джумаев, Павел Сергеевич
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Руководитель научной группы "Лаборатория ионно-плазменной и ионно-пучковой обработки материалов"
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Павел Сергеевич
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- ПубликацияТолько метаданныеInvestigation of Stainless Steel Obtained by Additive Technology as Applied to the Operating Conditions of Liquid Metal Heat-Exchange Systems(2020) Ladyko, M. A.; Eremin, A. G.; Logachev, I. A.; Sentyurina, Z. A.; Lyublinski, I. E.; Dzhumaev, P. S.; Джумаев, Павел Сергеевич© 2020, Pleiades Publishing, Ltd.Abstract: The properties of stainless steel grade GP1 obtained by additive technology (AT) by the method of selective laser melting (SLM) in relation to the operating conditions of liquid metal heat-exchange systems of power plants (vacuum density, corrosion effect of eutectic sodium and potassium alloy Na–K at temperature 700 ± 5°С) are investigated. The microstructure of GP1 steel has a fine structure with a characteristic size of structural components from 2 to 3 μm. The results of local chemical analysis of the identified structural components of the material showed a high degree of material homogeneity. The material is sealed, the flow of helium into the sample made by AT was no more than 4 × 10–10 (Pa m3)/s. Under the conditions of the tests performed, the corrosive effect of Na–K on the material is observed in the surface layers with a thickness of no more than 2 μm. The corrosion rate of the test material under test conditions was less than 0.01 mm/year, which, according to the existing classification of corrosion resistance, makes it possible to assign the test material under test conditions to the resistance group of extremely resistant. The results give grounds to continue research on a larger time base and in conditions close to the operating conditions of the heat-exchange systems of power plants (non-isothermal dynamic conditions), as well as to conduct research on other steels obtained by AT, for example, chromium-nickel corrosion-resistant steel of austenitic class with a high level of corrosion resistance in the environment of the liquid metal coolant Na–K of eutectic composition.
- ПубликацияТолько метаданныеHIGH-TEMPERATURE OXIDATION OF ZIRCONIUM ALLOYS WITH MAGNETRON SPUTTERED CHROMIUM COATINGS(2022) Isayev, R. Sh.; Safonov, D. A.; Dzhumaev, P. S.; Korenevskiy, E. L.; Исаев, Рафаэл Шахбаз Оглы; Джумаев, Павел Сергеевич; Кореневский, Егор ЛеонидовичLoss-of-coolant accidents (LOCAs) often lead to dire consequences. That’s why the global community are actively engaged in research aimed at creating accident tolerant fuels. One of the areas of such research is preserving zirconium alloys as the material for fuel-element claddings by creating corrosion-resistant coatings that would be in contact with the coolant. Chromium could be a prom-ising material to be used in such protective coatings as chromium oxide (Cr2O3) serves as an effective barrier for oxygen both in normal operation and in case of LOCA. Chromium coating hinders oxygen diffusion into the metal substrate and thus prevents embrittlement and failure of the fuel-element cladding. This paper describes the results of research studies that have been carried out in recent years and that look at the resistance of magnetron sputtered chromium coatings to high-temperature oxidation in water vapour up to 1,500o C. The paper demonstrates advantages and drawbacks of chromium coatings in high-temperature oxidation conditions. The focus is on understanding how regimes of magnetron sputtering influence the resistance of chromium coatings to high-temperature oxidation and how the structure and phase state of chromium coatings are related to their properties. The authors describe the optimal regimes of magnetron sputtering for obtaining dense coatings and examine the effect of the substrate temperature and the bias voltage on the structure and density of resulting coatings. High Power Impulse Magnetron Sputtering (HiPIMS) serves as an effective technique that helps enhance the density of coatings. The conclusion drawn is that in order to broaden the temperature range in which chromium coatings can effectively protect zirconium alloys from failure up to 1500o C, there should be a diffusion barrier between the surface of the fuel-element cladding and the chromium coating. The authors would like to thank B. A. Kalin, supervisor of this project, who had passed away before this publication was made. The staff of the Laboratory of Ion-Plasma and Ion-Beam Machining of Materials, a part of Department No. 9 at the National Research Nuclear University MEPhI, devote this paper to his memory. © 2022, Ore and Metals Publishing house. All rights reserved.
- ПубликацияТолько метаданныеApplying Scanning Contact Potentiometry for Monitoring Incipient Cracks in Steels(2019) Surin, V. I.; Polskij, V. I.; Osintsev, A. V.; Dzhumaev, P. S.; Сурин, Виталий Иванович; Польский, Валерий Игоревич; Осинцев, Андрей Вениаминович; Джумаев, Павел Сергеевич© 2019, Pleiades Publishing, Ltd. The processes of formation and growth of an incipient crack in EI847 steel have been studied by uniaxial constant-load tension testing on an INSTRON-5982 tensile testing machine using scanning contact potentiometry. The nucleus was detected at the sample surface within the yield strength domain and was stably monitored based on the readings of apparatus under higher loads until the moment of destruction.
- ПубликацияТолько метаданныеThermal fatigue damage of steel joints brazed with various nickel filler metals(2019) Penyaz, M. A.; Ivannikov, A. A.; Kalin, B. A.; Dzhumaev, P. S.; Иванников, Александр Александрович; Джумаев, Павел Сергеевич© E. V. Aryshnskii, V. Yu. Bazhin, R. Kawalla, 2019.Demands on the properties of constructions are constantly being increased and the technology of producing permanent joints is crucial for advancement of the high-tech industry. This investigation focuses on thermal fatigue of austenitic steel joints, brazed with nickel filler metals based on Ni - Cr - Si system. This type of fatigue has nonmechanical origin and arises from the cyclic variation of thermal stresses with temperature changes. For investigation selected temperature range is: From room temperature to 450 oC (low-cycle fatigue). Due to inhomogeneous thermal expansion or compression during thermal fatigue, thermal stresses and deformation arise and lead to microstructural changes in the joint zone. This can have a strong effect on the mechanical characteristics of the joint. Therefore, it is important to investigate the properties of the brazed seam after thermal cycling. In this work samples brazed various filler metals before and after thermocycling were evaluated using various methods. The microstructures were investigated and analysis by energy-dispersive X-ray spectroscopy (EDS) of the diffusion zone was carried out using electron microscope. The main regularities of the structure-phase state formation studied using electron backscatter diffraction (EBSD). Standard tests for the tensile strength of the samples were carried out. The result of this research is the prediction of the durability and reliability of brazed steel constructions operating under conditions of low-cycle temperature changes.
- ПубликацияТолько метаданныеExperimental investigation of the failure of steel AISI 316 by the methods of structural analyses(2019) AbuGhazal, A. A.; Dzhumaev, P. S.; Osintsev, A. V.; Polsky, V. I.; Surin, V. I.; Джумаев, Павел Сергеевич; Осинцев, Андрей Вениаминович; Польский, Валерий Игоревич; Сурин, Виталий ИвановичThe failure of reactor steel AISI 316 under tension was investigated by structural analysis and scanning contact potentiometry (SCP). In real time surface potentiograms were plotted by the change of which the growth of crack nucleus was tracked from its initiation till the stage of cup fracture formation. The nucleus of the microscopic crack on the potentiogram was first detected at the end of the next to the last cycle of testing at a load of 525 MPa in the yield region and then was persistently reproduced on potentiograms in subsequent tests up to the failure. The most noticeable changes in the parameters of dynamic waviness and roughness occurred at the moments of sharp crack growth. Using the results of the SCP method, three main stages of crack development were identified. In the first one, under loads corresponding to the conditional yield point, a nucleus was formed in the region of the maximum tangential stresses. This region of localization arises as a result of macroscopic loss of stability due to the significant mechanical energy accumulation by the system, which leads to an increase in the magnitudes of the plastic strain fluctuations. The second stage, the one of a progressive growth of the crack nucleus, is the longest in time and lasts from the moment of detection of the nucleus to the sample failure. The amplitude of the electrical potentials in the central part of the sample increased with the rise in intensity of the applied load which is associated with an increase in the inhomogeneity of the internal stress field around the nucleus, as well as the accelerating creep process and the growth of plastic strain in this region. At the pre-failure stage in the hardened surface layer, a macro-groove appears in the form of a standing deformation wave along the fracture line. Under the microscope, shear strain bands on the sample surface are also visible.
- ПубликацияТолько метаданныеSilicon MEMS Thermocatalytic Gas Sensor in Miniature Surface Mounted Device Form(2021) Samotaev, N.; Samotaev, N; Dzhumaev, P.; Oblov, K.; Pisliakov, A.; Самотаев, Николай Николаевич; Джумаев, Павел Сергеевич; Облов, Константин Юрьевич; Образцов, Иван СергеевичA reduced size thermocatalytic gas sensor was developed for the detection of methane over the 20% of the explosive concentration. The sensor chip is formed from two membranes with a 150 mu m diameter heated area in their centers and covered with highly dispersed nano-sized catalyst and inert reference, respectively. The power dissipation of the chip is well below 70 mW at the 530 degrees C maximum operation temperature. The chip is mounted in a novel surface mounted metal-ceramic sensor package in the form-factor of SOT-89. The sensitivity of the device is 10 mV/v%, whereas the response and recovery times without the additional carbon filter over the chip are <500 ms and <2 s, respectively. The tests have shown the reliability of the new design concerning the hotplate stability and massive encapsulation, but the high degradation rate of the catalyst coupled with its modest chemical power limits the use of the sensor only in pulsed mode of operation. The optimized pulsed mode reduces the average power consumption below 2 mW.
- ПубликацияТолько метаданныеFracture Parameters and Plasticity of the Zr–Nb–Sn–Fe Tubes with Different Hydrides Orientations during the Mechanical Testing(2024) Saburov, N. S.; Isaenkova, M. G.; Petrov, M. I.; Dzhumaev, P. S.; Исаенкова, Маргарита Геннадьевна; Петров, Марк Игоревич; Джумаев, Павел Сергеевич
- ПубликацияТолько метаданныеNonthermal Mechanism of Defect Formation in the CdHgTe Semiconductor on Exposure to Soft X-rays(2019) Sredin, V. G.; Ramakoti, R. S.; Anan'in, O. B.; Melekhov, A. P.; Gerasimov, I. A.; Bogdanov, G. S.; Novikov, I. K.; Frolova, I. V.; Dzhumaev, P. S.; Рамакоти, Рави Шрираджа; Мелехов, Андрей Петрович; Герасимов, Иван Александрович; Богданов, Глеб Сергеевич; Новиков, Игорь Кимович; Джумаев, Павел Сергеевич© 2019, Pleiades Publishing, Ltd.The effect of irradiation with soft X-rays produced by a laser plasma source equipped with an X-ray concentrator on the properties of the CdHgTe semiconductor are investigated. For this purpose, the mass concentration of atoms in the near-surface layer of the material is measured. It is demonstrated that the action of soft X-ray radiation leads to change in the solid-solution composition at the surface via a nonthermal mechanism and generates surface defects.
- ПубликацияТолько метаданныеStructure and Mechanical Properties of Electrolytic Chromium Coatings Deposited on the Inner Surface of Fuel Cladding Made of EP823-Sh Steel(2025) Elmanov, G. N.; Dzhumaev, P. S.; Isaev, R. Sh.; Yakovleva, A. D.; Елманов, Геннадий Николаевич; Джумаев, Павел Сергеевич; Исаев, Рафаэл Шахбаз Оглы
- ПубликацияТолько метаданныеDiffusion brazing of stainless steels influence of Ni-B filler alloy composition(2021) Ivannikov, A. A.; Penyaz, M. A.; Dzhumaev, P. S.; Bachurina, D. M.; Sevryukov, O. N.; Иванников, Александр Александрович; Джумаев, Павел Сергеевич; Севрюков, Олег Николаевич© 2020, International Institute of Welding.Stainless austenitic (0.12C-18Cr-10Ni-Ti, wt-%) and ferritic-martensitic (0.16C-12Cr-Mo-Si-V-Nb-B, wt-%) steels were joined by transient liquid phase diffusion bonding (also called diffusion brazing) with the filler metals based on Ni-Cr-Si-(Fe)-B at 1160 °C for different bonding times from 15 to 40 min. It is shown that the braze joints have a heterogeneous diffusion zone with a boride network which is formed during isothermal solidification. The influence of the filler metals composition on the joint microstructure and tensile strength was studied. It is established that the initial concentration of boron and chromium in the filler metal plays an important role in the formation of the microstructure. It is shown that the use of the filler metal with the optimized composition of Ni-20Cr-7.5Si-4.5Fe-1.5B makes it possible to obtain the most homogeneous structure, leading to the best tensile strength of the joint of about 500 ± 40 MPa.