Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-29418 Zeitschriftenartikel Epishin, A.; Fedelich, Bernard; Link, T.; Feldmann, Titus; Svetlov, I.L. Pore annihilation in a single-crystal nickel-base superalloy during hot isostatic pressing: Experiment and modelling Pore annihilation during hot isostatic pressing (HIP) was investigated in the single-crystal nickel-base superalloy CMSX-4 experimentally by interrupted HIP tests at 1288 °C/103 MPa. The kinetics of pore annihilation was determined by density measurement and quantitative metallography. Transmission electron microscopy of a HIPed specimen showed that the pores shrink via dislocation movement on octahedral glide planes. Theoretically pore closure under HIP condition was modelled by the finite element method using crystal plasticity and large strain theories. The modelling gives a similar kinetics of pore annihilation as observed experimentally, however somewhat higher annihilation rate. Amsterdam Elsevier 2013 Materials science and engineering A 586 342 349 10.1016/j.msea.2013.08.034 2016-02-20 OPUS4-55163 Zeitschriftenartikel Svetlov, I. L.; Epishin, A. I.; Petrushin, N. V.; Gerstein, G.; Nolze, Gert; Maier, H. J. Creep of Directionally Solidified Eutectics Ni/Ni3 Al-NbC under Thermal Cycling A nickel-based eutectic alloy with a γ/γ'-NbC structure was directionally solidified with a planar front. The specimens were tested for creep under sawtooth thermal cycling in the temperature range from 600 to 1100°C. It has been established that the lifetime under the conditions of thermal cycling is about five times shorter than it is predicted by the linear damage accumulation rule on the basis of results of isothermal creep tests. Faster creep under thermal cycling is caused by the rapid coarsening of the γ/γ' microstructure due to the periodic partial dissolution and reprecipitation of the γ' phase in heating and cooling half-cycles. Dordrecht Springer Science + Business Media 2022 Inorganic Materials: Applied research 13 4 1099 1108 10.1134/S2075113322040347 2022-07-04 OPUS4-54466 Zeitschriftenartikel Treninkov, I. A.; Petrushin, N. V.; Epishin, A. I.; Svetlov, I. L.; Nolze, Gert; Elyutin, E. S. Experimental Determination of Temperature Dependence of Structural-Phase Parameters of Nickel-Based Superalloy The temperature dependences of the periods of the crystal lattices of the γ and γ' phases, their dimensional mismatch (misfit), and volume fraction of the γ' phase of an experimental single-crystal hightemperature nickel-based alloy have been determined by X-ray diffraction analysis in the temperature range of 18-1150°C. The temperature ranges in which intense changes in the structural and phase characteristics of the alloy under study take place have been determined. Dordrecht Springer Science + Business Media 2022 Inorganic Materials: Applied Research 13 1 171 178 10.1134/s2075113322010373 2022-03-14 OPUS4-54379 Zeitschriftenartikel Epishin, A. I.; Petrushin, N. V.; Svetlov, I. L.; Nolze, Gert Model for Forecasting Temperature Dependence of γ/γ' Misfit in Heat-Resistant Nickel Alloys An analytical model for forecasting the temperature dependence of γ/γ' misfit in heat-resistant nickel alloys is proposed. The model accounts for the concentration dependences of the periods of crystalline lattices of the γ and γ' phases (Vegard law), thermal expansion of the γ and γ' lattices, and dissolution of the γ' phase at high temperatures. Adequacy of calculations of misfit is confirmed by comparison with the results of measurements using methods of X-ray and neutron diffraction. The model is applied for development of a nickel alloy with positive misfit. Springer 2022 Inorganic Materials: Applied Research 13 1 7 16 10.1134/S2075113322010105 2022-02-21 OPUS4-53132 Zeitschriftenartikel Epishin, A. I.; Fedelich, Bernard; Viguier, B.; Schriever, Sina; Svetlov, I. L.; Petrushin, N. V.; Saillard, R.; Proietti, A.; Poquillon, D.; Chyrkin, A. Creep of single-crystals of nickel-base γ-alloy at temperatures between 1150 °C and 1288 °C A γ-analogue of the superalloy CMSX-4 that does not contain the strengthening γ′ -phase and only consists of the γ-solid solution of nickel has been designed, solidified as single-crystals of different orientations, and tested under creep conditions in the temperature range between 1150 and 1288 °C. The tests have revealed a very high creep anisotropy of this alloy, as was previously found for CMSX-4 at supersolvus temperature of 1288 °C. This creep anisotropy could be explained by the dominance of 〈011〉{111} octahedral slip. Furthermore, the analysis of the creep data has yielded a high value of the creep activation energy, Qc≈442 kJ/mol, which correlates with the high activation energy of Re diffusion in Ni. This supports the hypothesis that dislocation motion in the γ-matrix of Re-containing superalloys is controlled by the diffusion of the Re atoms segregating at the dislocation core. The Norton stress exponent n is close to 5, which is a typical value for pure metals and their alloys. The absence of γ′ -reprecipitation after high-temperature creep tests facilitates microstructural investigations. It has been shown by EBSD that creep deformation results in an increasing misorientation of the existing low angle boundaries. In addition, according to TEM, new low angle boundaries appear due to reactions of the a/2 〈011〉 mobile dislocations and knitting of new networks. Amsterdam Elsevier 2021 Materials Science & Engineering A 825 1 13 10.1016/j.msea.2021.141880 2021-08-24 OPUS4-52097 Zeitschriftenartikel Epishin, A.; Fedelich, Bernard; Finn, Monika; Künecke, Georgia; Rehmer, Birgit; Nolze, Gert; Leistner, C.; Petrushin, N.; Svetlov, I. Investigation of Elastic Properties of the Single-Crystal Nickel-Base Superalloy CMSX-4 in the Temperature Interval between Room Temperature and 1300 °C The elastic properties of the single-crystal nickel-base superalloy CMSX-4 used as a blade material in gas turbines were investigated by the sonic resonance method in the temperature interval between room temperature and 1300 °C. Elastic constants at such high temperatures are needed to model the mechanical behavior of blade material during manufacturing (hot isostatic pressing) as well as during technical accidents which may happen in service (overheating). High reliability of the results was achieved using specimens of different crystallographic orientations, exciting various vibration modes as well as precise measurement of the material density and thermal Expansion required for modeling the resonance frequencies by finite element method. Combining the results measured in this work and literature data the elastic constants of the gamma and gamma' phases were predicted. This prediction was supported by measurement of the temperature dependence of the gamma'fraction. All data obtained in this work are given in numerical or analytical forms and can be easily used for different scientific and engineering calculations. MDPI 2021 Crystals 11 2 152 urn:nbn:de:kobv:b43-520972 10.3390/cryst11020152 https://creativecommons.org/licenses/by/4.0/deed.de 2021-02-10 OPUS4-53110 Zeitschriftenartikel Treninkov, И. A; Petrushin, N. V.; Epishin, А. I.; Svetlov, I. L.; Nolze, Gert; Elyutin, E. S. ЭКСПЕРИМЕНТАЛЬНОЕ ОПРЕДЕЛЕНИЕ ТЕМПЕРАТУРНОЙ ЗАВИСИМОСТИ СТРУКТУРНО-ФАЗОВЫХ ПАРАМЕТРОВ НИКЕЛЕВОГО ЖАРОПРОЧНОГО СПЛАВА Методом рентгеноструктурного анализа в интервале температур 18—1150 °С определены температурные зависимости периодов кристаллических решеток γ- и γ'-фаз, их размерно-го несоответствия (мисфит) и объемной доли γ'-фазы экспериментального монокристал-лического жаропрочного никелевого сплава. Определены диапазоны температур, в которых происходят интенсивные изменения структурно-фазовых характеристик исследованного сплава. 2021 ФИЗИЧЕСКИЕ ОСНОВЫ МАТЕРИАЛОВЕДЕНИЯ 7 3 12 10.31044/1684-579x-2021-0-7-3-12 2021-08-18 OPUS4-31641 Beitrag zu einem Tagungsband Epishin, A.I.; Link, T.; Fedelich, Bernard; Svetlov, I.L.; Golubovskiy, E.R. Hot isostatic pressing of single-crystal nickel-base superalloys: mechanism of pore closure and effect on mechanical properties Pore annihilation was investigated in the single-crystal nickel-base superalloy CMSX-4. HIP tests at 1288 °C/103 MPa were interrupted at different times, then the specimens were investigated by TEM, metallography and density measurements. The kinetics of pore annihilation was determined. The pore closure mechanism was identified as plastic deformation on the octahedral slip systems. A model describing the kinetics of pore closure has been developed on the base of crystal plasticity and large strain theory. Mechanical tests with the superalloy CMSX-4 and the Ru-containing superalloy VGM4 showed, that HIP significantly increases the fatigue life at low temperatures but has no effect on creep strength. EDP Sciences 2014 Eurosuperalloys 2014 - 2nd European symposium on superalloys and their applications 14 Eurosuperalloys 2014 - 2nd European symposium on superalloys and their applications Giens, France 12.05.2014 16.05.2014 08003-1 08003-6 urn:nbn:de:kobv:b43-316410 10.1051/matecconf/20141408003 https://creativecommons.org/licenses/by/4.0/deed.de 2016-02-20 OPUS4-37983 Zeitschriftenartikel Epishin, A.; Link, T.; Svetlov, I. L.; Nolze, Gert; Saliwan Neumann, Romeo; Lucas, H. Mechanism of porosity growth during homogenisation in single crystal nickel-based superalloys Several mechanisms for porosity growth in single crystal nickel-based superalloys during homogenisation heat treatment have been proposed in the literature. They were carefully checked using different experimental methods, namely quantitative light microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and density measurements. It is shown that the main mechanism is the Kirkendall-Frenkel effect, i.e. generation of voids due to uncompensated efflux of Al atoms from dissolving γ/γ′-eutectic areas. The Al diffusion is supported by the afflux of vacancies from surrounding γ-matrix which results in porosity growth. This conclusion is confirmed by the estimation of the vacancy afflux towards the dissolving eutectic. Carl Hanser Verlag 2013 International Journal of Materials Research 104 8 776 782 2016-10-31 OPUS4-37980 Zeitschriftenartikel Epishin, A. I.; Link, T.; Nolze, Gert; Svetlov, I. L.; Bokshtein, B. S.; Rodin, A. O.; Saliwan Neumann, Romeo; Oder, Gabriele Diffusion processes in multicomponent nickel-base superalloy-nickel system Optical and scanning electron microscopy, as well as electron microprobe analysis and electron backscatter diffraction, have been used to study diffusion processes that occur in a diffusion pair that consistsof a single-crystal CMSX-10 nickel-base superalloy and polycrystalline nickel, at temperatures of 1050-1250°C. It has been found that, in this system, the distributions of γ-stabilizing elements (Cr, Co, W, and Re) are described by the Boltzmann solution for diffusion between two semiinfinite plates of a binary alloy. The processing of these distributions has shown that the diffusion coefficients of Cr, Co, W, and Re in the multicomponent system are close to those in binary alloys of these elements with Ni. The diffusion redistribution of the elements leads to the dissolution of the γ′ phase in the nickel-base superalloy, growth of nickel grains toward the superalloy constituent of the diffusion pair, and the formation of porosity on both sides of the migrating interface, which is determined from a crystal misorientation of the alloy single crystal and nickel grains. 2014 The Physics of Metals and Metallography 115 1 21 29 2016-10-31