Персона: Иванников, Александр Александрович
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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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Александр Александрович
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- ПубликацияТолько метаданныеAlloying-dependent microstructure influence on corrosion resistance of AISI 321 cell joints brazed by Ni-based filler metals(2020) Penyaz, M. A.; Popov, N. S.; Ivannikov, A. A.; Sevryukov, O. N.; Попов, Никита Сергеевич; Иванников, Александр Александрович; Севрюков, Олег Николаевич© 2020, "Ore and Metals" Publishing house. All rights reserved.Cellular structures that are widely used as filters and heat exchangers usually operate under high loads and aggressive environments. Corrosion attack can lead to the destruction of the most vulnerable elements of the structure and, as a result, to the failure of the device. This study is devoted to the influence of the elemental composition of nickel-based brazing alloys on the corrosion resistance of brazed joints. Nickel-based brazing alloys based on Ni – Cr – Si – B (BNi-2, BNi-5a) and Ni – Cr – P (BNi-7) systems, and experimental compositions, were selected for the study. The brazing modes were selected according to differential thermal analysis (DTA). The microstructure of the joints was studied using energy-dispersive Х-ray spectroscopy (EDS) on a scanning electron microscope (SEM). The effect of brazing temperature and holding time on grain size and corrosion resistance were evaluated. Corrosion tests were performed in a boiling mixture of CuSO4 and H2SO4 solutions for 8 hours. The obtained microstructures of the brazed joints with different filler metals and different braze modes, before and after corrosion tests, were compared. The erosion activity of brazing alloys was evaluated, and it was found that an increase in the amount of chromium reduces the damages caused by erosion. The relationships between the chemical composition of the filler metals and the brazed joint, the structural-phase state of the joint and the level of corrosion damage are revealed. The influence of elements such as boron, silicon, molybdenum, phosphorous and chromium on the corrosion resistance of the brazed joint is shown. It was found that BNi-5a, BNi-7 and FM04 show the best corrosion resistance. In brazed joints obtained with low-chromium filler metals, a strong dissolution of the zone adjacent to the base material was detected. The purpose of the study is to determine the influence of elements often used in brazing alloys, as well as the structural-phase state, on the corrosion resistance of the brazed joint. on the corrosion resistance of the brazed joint.
- ПубликацияТолько метаданныеStudy of Ti-Zr-Nb-Be filler metal interaction with silicon carbide based ceramics during brazing process(2020) Eroshenko, A. A.; Ivannikov, А. A.; Fedotov, I. V.; Suchkov, A. N.; Dzhumaev, P. S.; Sevryukov, O. N.; Иванников, Александр Александрович; Федотов, Иван Владимирович; Сучков, Алексей Николаевич; Джумаев, Павел Сергеевич; Севрюков, Олег Николаевич© Published under licence by IOP Publishing Ltd.This work is devoted to an analysis of the composition of a silicon carbide based ceramic brazed seam as a result of its interaction with rapidly quenched titanium-zirconium-niobium-beryllium filler metal. Structural-phase studies based on EDX and EBSD analysis, mechanical shear tests, and microhardness measurements of brazed joints were carried out. It was shown that titanium, zirconium, and niobium silicides as well as particles of titanium carbosilicides and silicon carbides in the silicon matrix are formed in the brazed seam, probably because of the presence of free silicon in the base material, which leads to increasing joint microhardness and unstable shear strength results.
- ПубликацияТолько метаданныеManufacturing of high entropy alloy in the Ni-Nb-Co-Fe-Cr system by rapidly solidification method for oxide ceramic brazing(2020) Gabov, A. I.; Ivannikov, А. A.; Sevryukov, O. N.; Иванников, Александр Александрович; Севрюков, Олег Николаевич© Published under licence by IOP Publishing Ltd.This paper presents results of research of high-entropy alloys of the Ni-Nb-Co-Fe-Cr system in the as-cast state and after rapid quenching from the melt. The results of experiments on obtaining a brazed joint of aluminum-oxide ceramics with using the filler metal of this system and the results of a studying this joint are presented. Differential thermal analysis (DTA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray microanalysis (EDX) and measurement of microhardness were used as experimental research methods. The liquidus and solidus temperatures of high-entropy alloy Nb0.73CoCrFeNi2.1 were determined. The phase composition of alloys of the Ni-Nb-Co-Fe-Cr system was studied. It was shown, that alloys of this system can be used as filler metal to create a joint between ceramics. The microhardness of the brazed seam was studied. Based on these results the brazing mode for samples of aluminum-oxide ceramics with using high-entropy alloy Nb0.73CoCrFeNi2.1 as a filler metal was chosen.
- ПубликацияТолько метаданныеMicrostructure formation and mechanical properties of isothermally-solidified titanium alloy joints brazed by a Ti - Zr - Cu - Ni - Be amorphous alloy foil(2020) Morokhov, P. V.; Ivannikov, А. A.; Popov, N. S.; Sevryukov, O. N.; Морохов, Павел Владимирович; Иванников, Александр Александрович; Попов, Никита Сергеевич; Севрюков, Олег НиколаевичTwo titanium alloys, OT4 and VT6-c, with a pseudo-alpha and alpha + beta structure, respectively, were brazed using transient liquid phase (TLP) bonding. To obtain high strength joints an amorphous foil (Ti - 12Zr - 22Cu - 12Ni - 1.5 Be - 0.8V wt.%) was used. Based on microstructural studies and analysis of two- and three-component phase diagrams, the mechanism of the microstructural evolution of the brazed seams of titanium alloys OT4 and VT6-c is described. Brazing at 800 oC with exposure for 0.5 h leads to the formation of a heterogeneous structure consisting of Widmanstatten, eutectoid, and eutectic. Brazed OT4 and VT6-c joints with the presence of a eutectic layer in the centre show low mechanical properties; their ultimate strength lies in a range from 200 to 550 MPa. Increasing the brazing temperature to 840 degrees C and the exposure time to 2 h, leads to the disappearance of the brittle eutectic component from the seam. This structure typically consists of Widmanstatten with a small number of eutectoid fractions. Joints with the absence of a eutectic layer in the brazed seam demonstrate a strength equal to the base titanium alloys. In this case, failure occurs in the base metal. For brazed samples from the OT4 alloy, the tensile strength value is sigma(b) = 750 +/- 3 MPa, and for samples from VT6- c, sigma(b) = 905 +/- 3 MPa.
- ПубликацияТолько метаданныеEffect of high-temperature brazing with a nickel-based STEMET 1301A brazing alloy on the unbrazing temperature of 12Kh18N10T steel joints(2020) Ivannikov, А.; Krasnova, E.; Penyaz, M.; Popov, N.; Melnikov, А.; Sevryukov, O.; Иванников, Александр Александрович; Попов, Никита Сергеевич; Севрюков, Олег Николаевич© 2020, Springer-Verlag London Ltd., part of Springer Nature.The challenges facing the creation of brazed joints of 12Kh18N10T (AISI 321) austenitic stainless steel with high unbrazing temperatures for extreme working conditions in aerospace appliances are considered in this study. An amorphous-nanocrystalline nickel–based foil, Ni-7Cr-4.5Si-3.5Fe-2.6B, wt.%, is used for brazing the steel. Experiments on brazing regimes with various temperatures (1070–1160 °С) and times of exposition (15–80 min) are carried out. The formation of Ni-based solid solutions with different Cr, Fe, Mn, Si, and Ti contents in the brazed seam is detected for all brazing regimes. Using Thermo-Calc software, the liquidus temperature located in a range between 1268 and 1388 °С is calculated. To verify the calculated values, the unbrazing temperature is experimentally determined for specimens, with a composition of the solid solutions, formed in the center of the brazed seam during brazing at 1160 °С/15 min, 1070 °С/15, and 1160 °С/80 min. The experimental results deviate from values computed by Thermo-Calc by no more than 54 °С. The experimental samples obtained using the 1070 °C/40 min and 1100 °C/80 min regimes demonstrate high unbrazing temperatures equal to 1303 °C and > 1330 °C, respectively, which corresponds to the calculations with an accuracy of 2.5%. Taking into account the combination of properties (strength and unbrazing temperature), brazing regimes of heating to 1070–1100 °C and an exposure time for 15–40 min can be recommended for the production of high-strength joints with high unbrazing temperatures.
- 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 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.
- ПубликацияТолько метаданныеDevelopment of rapidly-quenched al-ge-si filler alloys for the joining of stainless steel aisi 304 and aluminum alloy aa6082(2021) Fedorov, V.; Uhlig, T.; Wagner, G.; Ivannikov, А.; Abramov, A.; Penyaz, M.; Bachurina, D.; Suchkov, A.; Morokhov, P.; Sevryukov, O.; Иванников, Александр Александрович; Абрамов, Антон Владиславович; Сучков, Алексей Николаевич; Морохов, Павел Владимирович; Севрюков, Олег Николаевич© 2021 by the authors. Licensee MDPI, Basel, Switzerland.Aluminum alloys based on the Al-Ge-Si system with a germanium content of up to 40 wt.%, promising for the brazing of aluminum alloy AA6082 with the stainless steel AISI 304, were studied. The temperature characteristics and microstructural and mechanical properties of the filler alloys were systematically investigated. Differential scanning calorimetry showed that with an increase in the germanium content from 28.0 to 40.0 wt.%, the liquidus temperature of the filler alloys decreased from 514.8 to 474.3◦ C. X-ray diffraction analysis and electron microscopy data showed that the foil of the filler alloys reveals a homogeneous structure. The ingots of the alloys contain two eutectics, the first of which consists of a solid solution of (Al, Ge) with a solid solution of (Ge, Si), and the second consists of a solid solution of (Al, Ge) with a solid solution based on (Ge). When the content of germanium increases from 28.0 to 40.0 wt.%, a separation of the faceted solid solution particles (Ge, Si) and an increase in their number could be observed. Nanohardness measurements showed that the (Ge, Si) and (Ge) solid solutions had similar nanohardness, with values of 11.6 and 10.2 GPa, respectively. Simultaneously, the Al solid solution and the intermetallic Al7 Ge2 Fe phase exhibited significantly lower nanohardness values of 0.7 and 6.7 GPa, respectively. Brinell hardness measurements showed that the ingots of the filler alloys were sufficiently ductile and had a hardness comparable to that of AA6082, which is used for brazing with AISI 304 stainless steel. The obtained results for the studied ingots and the rapidly quenched foils can be used to predict the forming structure of the seam after brazing and adjusted for diffusion processes occurring between the brazed materials and the studied filler alloys.
- ПубликацияТолько метаданныеOverview of nickel-based filler metals for brazing of austenitic stainless steels(2021) Penyaz, M. A.; Ivannikov, А. A.; Sevryukov, O. N.; Kalin, B. A.; Иванников, Александр Александрович; Севрюков, Олег НиколаевичFor the manufacture of thin-walled precision structures with complex geometry, the method of brazing is used. It allows to obtain joints with a given structural-phase state, high mechanical characteristics and resistance to corrosion. This overview examines alloys based on copper, precious metals, nickel and iron, which are actively used for joining steels. The data on the operational characteristics of the joints obtained by brazing using nickel- based filler metals are presented and structured. Special attention is paid to nickel braze alloys based on Ni - B, Ni - Si - B, Ni - Cr - B, Ni - Cr - Si, Ni - Cr - Si - B, Ni - Mn, Ni - Cr - P, Ni - Si - Be systems. Such alloys are the most widespread and applicable throughout the world. The overview describes the main phases that are formed in the seams and the heat-affected zones of joints. The dependences of the technological parameters of the process, such as the temperature-time mode of brazing and the size of the gap on the microstructure of the joints and their mechanical characteristics, are shown. The corrosion resistance of steel joints brazed by various nickel-based filler metals is considered. The overview is based on the extensive experience of MEPhI in the production and development of rapidly solidified amorphous-crystalline foils based on nickel. In addition to the world experience, the overview considers works of the research team of the MEPhI laboratory, which has been working on this topic since 1995. This overview will help technologists and designers of energy-intensive equipment to determine the trajectory for the selection of the filler metal composition to obtain the optimal technological parameters, mechanical characteristics and corrosion resistance of the joints applicable to a specific design problem.
- ПубликацияТолько метаданныеEFFECT OF HEAT TREATMENT ON THE PROPERTIES OF RAPIDLY QUENCHED Al – Ge – Si ALLOYS(2022) Ivannikov, А. A.; Abramov, A. V.; Sevryukov, O. N.; Suchkov, A. N.; Kalin, B. A.; Иванников, Александр Александрович; Абрамов, Антон Владиславович; Севрюков, Олег Николаевич; Сучков, Алексей НиколаевичThis paper examines Al – Ge – Si alloys containing up to 40 wt. % germanium that can potentially be used for brazing corrosion resistant steels to high-strength aluminium alloys. Using ultrarapid quenching, ingots of the above alloys were converted into 55±5 μm thick bands. Properties of both ingots and bands were methodically studied, and effect of heat treatment on the properties of ingots and bands – determined. Optimal regimes of heat treatment for bands were tested that help achieve the required plasticity. Homogenous and heterogenous materials were brazed together. X-ray phase analysis and electron microscopy showed that rapidly quenched bands have a homogenous structure and contain a eutectic comprised of solid solutions (Al, Ge) and (Si, Ge) and a metastable compound Al6Ge5. The ingots of the alloys consist of two eutectics. The first one consists of solid solutions (Al, Ge) and (Si, Ge), while the second one comprises a solid solution (Al, Ge) and a Ge-based solid solution. The bands have a nanocrystalline structure. Having measured microhardness and plasticity of the bands, the authors identified the best regime of heat treatment, which is 300oC/10 min. A series of pilot tests was conducted to analyze the applicability of the studied alloys as filler metals. For this, aluminium alloy AA6082 was brazed to corrosion resistant steel AISI 304 and a heterogenous joint was made. A metallographic study revealed no compromized integrity or defects in any of the brazed joints. © 2022, Ore and Metals Publishing house. All rights reserved.
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