Персона: Иванников, Александр Александрович
Загружается...
Email Address
Birth Date
Научные группы
Non-discoverable
Организационные подразделения
Организационная единица
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.
Статус
Фамилия
Иванников
Имя
Александр Александрович
Имя
25 results
Результаты поиска
Теперь показываю 1 - 10 из 25
- ПубликацияОткрытый доступOverview of the mechanical properties of tungsten/steel brazed joints for the demo fusion reactor(2021) Bachurina, D.; Vorkel, V.; Suchkov, A.; Gurova, J.; Ivannikov, А.; Penyaz, M.; Fedotov, I.; Sevryukov, O.; Kalin, B.; Сучков, Алексей Николаевич; Гурова, Юлия Александровна; Иванников, Александр Александрович; Федотов, Иван Владимирович; Севрюков, Олег Николаевич© 2021 by the authors. Licensee MDPI, Basel, Switzerland.A Demonstration (DEMO) thermonuclear reactor is the next step after the International Thermonuclear Experimental Reactor (ITER). Designs for a DEMO divertor and the First Wall require the joining of tungsten to steel; this is a difficult task, however, because of the metals’ physical properties and necessary operating conditions. Brazing is a prospective technology that could be used to solve this problem. This work examines a state-of-the-art solution to the problem of joining tungsten to steel by brazing, in order to summarize best practices, identify shortcomings, and clarify mechanical property requirements. Here, we outline the ways in which brazing technology can be developed to join tungsten to steel for use in a DEMO application.
- ПубликацияОткрытый доступMicrostructure, residual stresses, and strain‐rate‐dependent deformation and fracture behavior of aisi 304l joints brazed with nicrsib filler metals(2021) Otto, J. L.; Mohring, K.; Gerdes, L.; Schaum, T.; Penyaz, M.; Ivannikov, А.; Kalin, B.; Иванников, Александр Александрович© 2021 by the authors. Submitted for possible open access.The knowledge of alloy–process–structure–property relationships is of particular interest for several safety‐critical brazed components and requires a detailed characterization. Thus, three different nickel‐based brazing filler metals were produced with varying chromium and molyb-denum content and were used to braze butt joints of the austenitic stainless steel AISI 304L under vacuum. Two holding times were used to evaluate diffusion‐related differences, resulting in six specimen variations. Significant microstructural changes due to the formation and location of bo-rides and silicides were demonstrated. Using X‐ray diffraction, alloy‐dependent residual stress gra-dients from the brazing seam to the base material were determined and the thermal‐induced residual stresses were shown through simulations. For mechanical characterization, impact tests were carried out to determine the impact toughness, as well as tensile tests at low and high strain rates to evaluate the strain‐rate‐dependent tensile strength of the brazed joints. Further thermal, electri-cal, and magnetic measurements enabled an understanding of the deformation mechanisms. The negative influence of brittle phases in the seam center could be quantified and showed the most significant effects under impact loading. Fractographic investigations subsequently enabled an enhanced understanding of the fracture mechanisms.
- ПубликацияТолько метаданныеMicrostructure Influence on Corrosion Resistance of Brazed AISI 304L/NiCrSiB Joints(2021) Penyaz, M.; Otto, J. L.; Popov, N.; Ivannikov, А.; Kalin, B.; Попов, Никита Сергеевич; Иванников, Александр АлександровичThe characterization of corrosion resistance, which is essential to estimate the lifetime of brazed joints in corrosive environments, is of central importance for many industrial applications and a basic requirement for the reliable and economic operation of brazed components. High temperature vacuum brazing with thin amorphous-crystalline foils is used for numerous applications such as exhaust gas heat exchangers. In this study one industrial BNi-5a (R) and two experimental rapidly solidified filler metal foils of Ni7Cr7.5Si4Fe1.5B and Ni20Cr7.5Si4Fe4Mo1.5B wt% were used to braze joints of AISI 304L. In addition, two holding times at 1160 degrees C were chosen to investigate the effect of the resulting microstructural differences on corrosion resistance. Especially the amount and distribution of borides and silicides within the brazing seam could be changed by the time-dependent diffusion processes, as could be shown by metallographic cross sections. Accelerated intercrystalline corrosion tests were carried out to evaluate the influence of the microstructure on the corrosion depth and damage mechanisms. Additionally, potentiodynamic polarization measurements in synthetic exhaust gas condensate as an application-oriented corrosion medium were performed for a comparative evaluation of corrosion properties and rate. The combination of high chromium-containing filler metal and increased holding time, which led to a more homogeneous microstructure, resulted in a more than five times improved corrosion resistance within both investigations.
- ПубликацияТолько метаданныеStructure and mechanical properties of three-layer composites obtained by magnetic pulse welding of titanium and Zr-based metallic glass(2024) Lazurenko, D. V.; Ivannikov, А. A.; Anisimov, A. G.; Popov, N. S.; Иванников, Александр Александрович; Попов, Никита Сергеевич
- ПубликацияОткрытый доступEffect of phase formation due to holding time of vacuum brazed AISI 304L/NiCrSiB joints on corrosion fatigue properties(2020) Otto, J. L.; Schmiedt-Kalenborn, A.; Knyazeva, M.; Walther, F.; Penyaz, M.; Ivannikov, А.; Kalin, B.; Иванников, Александр Александрович© 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Whether in turbine components or exhaust gas heat exchangers, vacuum-brazed nickel-based joints are subjected to varying cyclical loads during their applications, often in corrosive environments. The microstructure of the brazed seam, which is determined by the alloy composition and the brazing process parameters, is essential for the service life. In this experimental study a modified BNi-5a foil was produced and used to braze cylindrical AISI 304L butt joints with two different holding times. Using energy dispersive spectroscopy analyses, a direct correlation of the element distribution at the brazing seam with the holding time was detected as a result of diffusion processes. Individual phases were identified, and it could be shown that the longer holding time led to a reduction of borides and silicides as well as to a more even microhardness curve through the seam. The effect of the microstructure on the corrosion fatigue properties was evaluated using multiple amplitude tests by a stepwise increase of the maximum stress amplitude in synthetic exhaust gas condensate. Thereby, improved corrosion fatigue and cyclic deformation behaviors were achieved for the more homogeneous microstructure. Afterwards, topography analyses of the fracture surfaces enabled an understanding of microstructure-dependent damage mechanisms including fatigue crack initiation and propagation.
- 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.
- «
- 1 (current)
- 2
- 3
- »