Персона:
Шульга, Андрей Васильевич

Организационные подразделения

Организационная единица

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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Шульга

Имя

Андрей Васильевич

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Теперь показываю 1 - 10 из 19

Только метаданные
"An Investigation of the Microstructure and Mechanical Properties of the PM HIP Compacts of the High Temperature Ti-Based Alloy Fabricated Using the Rapidly Quenched Powder Produced by PREP-Technique"
(2020) Shulga, A. V.; Шульга, Андрей Васильевич
© European Powder Metallurgy Association (EPMA)A multi-scale investigation of the microstructure of the PM HIP compacts of the high temperature Ti-based alloy for gas turbine compressor disks was performed. The rapidly quenched spherical powder of the high temperature (α+β) Ti-based alloy manufactured by PREP-technique was used. The effect of the PM HIP parameters on the microstructure and mechanical properties of the PM HIP compacts was revealed. Methods of metallography, SEM, EDX, OIM were used in this study. The formation of the fully lamellar and also bimodal microstructures under the PM HIP compacts fabrication was revealed depending on the HIP temperature and also due to the preliminary heat treatment of the PREP-powder. PM HIP in the (α+β) field preserves the hereditary boundaries of the powder particles, while PM HIP in the field of the β phase is characterized by the effect of collective recrystallization. The correlation of the microstructure features with mechanical properties was established.
Только метаданные
Regularities of the microstructure formation of rapidly quenched powder of the high temperature ti-based alloy produced by PREP-technique
(2019) Shulga, A. V.; Шульга, Андрей Васильевич
© European Powder Metallurgy Association (EPMA)A multi-scale investigation was performed of the microstructure of the rapidly quenched spherical powder particles (granules) of the high temperature (α+β) Ti-based alloy fabricated by PREP-technique for production further by PM HIP technology compressor disk for gas turbine. Methods of metallography, SEM, EDX, EBSD were used to study microstructure in the granules of various sizes. Effects of granules size and vacuum heat treatment at temperatures in the (α+β) and β phase fields on the regularities of the granules microstructure formation were revealed. Dendrite microstructure of β phase grains was detected in the rapidly quenched as-atomized PREP-powder. Dendrite segregation of alloying elements was detected only in the larger particles in particular for Mo. In the smaller particles was observed formation of the cellular structure. Features of the transformation of the as-atomized microstructure with formation of the fully lamellar and also bimodal microstructures under the heat treatment were revealed.
Только метаданные
Anomalous particles (Granules) in PREP-powders - I. A multiscale study of the heated zone of rotating electrode under PREP manufacturing of the rapidly quenched powder of Ni-based superalloy
(2019) Shulga, A. V.; Шульга, Андрей Васильевич
© European Powder Metallurgy Association (EPMA)The composition uniformity of the rapidly quenched PREP-powder particles of the high temperature Ni-based superalloys and stainless steels is characterized by formation of the anomalous particles (granules) with the essentially different content mainly of the microalloyng interstitial elements carbon and boron. A detailed multiscale experimental study of microstructure of the Ni-based superalloy electrode after its using for PREP-manufacturing of the rapidly quenched powder was performed with the aim to reveal the mechanisms of the anomalous granules formation. Methods of metallography, activation autoradiography on carbon, track autoradiography on boron, SEM, EDS, EBSD were used. Intensive migration of boron to the surface of electrode due to the formation of thermal macro cracks was observed in the crater of electrode. Carbon behavior is determined by the formation of a thin melt layer on the crater surface. The mechanisms of the revealed behavior of boron and carbon under PREP- atomization are proposed.
Только метаданные
The Nature of Anomalous Particles (Granules) in Rapidly Quenched PREP Powders: I. A Multiscale Study of the Heating Zone of the Rotating Electrode Used to Obtain the Rapidly Quenched PREP Ni-Based Superalloy Powder
(2019) Shulga, A. V.; Шульга, Андрей Васильевич
© 2019, Pleiades Publishing, Ltd.The uniformity of composition of rapidly quenched PREP particles of the powder of high temperature Ni-based superalloys and stainless steels is characterized by an important feature—the occurrence of anomalous particles (granules) with a significantly different content, mainly of microalloying interstitial elements, carbon and boron, as well as active carbide- and boride-forming alloying elements. A detailed multi-scale experimental study of the heating zone of the crater of the Ni-based superalloy electrode after its use to obtain rapidly quenched PREP powder was carried out in order to find the nature and mechanisms of the formation of anomalous granules. Direct nuclear physics methods of activation autoradiography on carbon, track autoradiography on boron, metallography, SEM, EDX, OIM were used. In the electrode crater, the heat-affected zone (HAZ) and the partially melted zone (PMZ) were detected. Intense migration of boron to the electrode surface due to the formation of thermal macrocracks was also revealed. The behavior of carbon is determined by the formation of a thin layer of melt on the surface of the crater. The features of the evolution of the terminal solidification region TSR and incipiently melted regions IMR, the main type of heterogeneity of the composition of the dendritic structure of Ni-based superalloys and stainless steels, are revealed. The interrelation of the evolution of these areas is established, which is a consequence of the thermodynamic principle of the reversibility of the processes of solidification and melting, respectively, in the smelting of an ingot electrode and in the process of subsequent atomization. The analysis of the influence of the behavior of boron, carbon, and the characteristics of the crater structure on the nature and mechanism of the formation of anomalous granules using the PREP method for producing rapidly quenched powder of the Ni-based superalloy is performed.
Только метаданные
A comparative study of the microstructure and mechanical properties of the high temperature Ti-based alloy products fabricated by PM HIP using the rapidly quenched powder and by traditional technology by PREP-technique
(2021) Shulga, A. V.; Шульга, Андрей Васильевич
Только метаданные
The Nature of Anomalous Particles (Granules) in Rapidly Quenched PREP Powders: III. Multiscale Study of Behavior of Boron and Carbon in PM HIP Compacts of High Temperature Ni-Based Superalloys under Hot Deformation and Heat Treatment
(2021) Shulga, A. V.; Шульга, Андрей Васильевич
© 2021, Pleiades Publishing, Ltd.Abstract: Occurrence of anomalous particles (granules) with significantly different concentrations of microalloying interstitial elements of carbon and boron is an important characteristic of composition homogeneity of rapidly quenched powders of high temperature Ni-based superalloys and stainless steels produced by the PREP method. Detailed multiscale experimental study of behavior of boron and carbon in PM HIP compacts of Ni-based superalloys under hot deformation and heat treatment has been performed. Direct nuclear methods of activation autoradiograph on carbony by the reaction 12C(d,n)13N and track autoradiograph on borony by the reaction 10B(n,α)7Li, metallography, SEM, EDX, and OIM have been used to reveal features of microstructure evolution of anomalous granules in PM HIP compacts of high temperature Ni-based superalloys. Significant influence of hot deformation and heat treatment on behavior of boron and carbon in PM HIP compacts of high temperature Ni-based superalloys has been detected. Significant differences in evolution of carbon and boron have been detected and discussed. A schematic TTT diagram is proposed for precipitation of the boride phase in comparison with precipitation of the carbide and γ' phases.
Только метаданные
Anomalous Particles (Granules) In PREP-Powders. A Multiscale Study Of The Structure Evolution Of The PM HIP Stainless Steels Under Hot Deformation And Heat Treatment
(2022) Shulga, A. V.; Шульга, Андрей Васильевич
Только метаданные
Nature of Anomalous Particles (Granules) in Rapidly Quenched PREP Powders: IV. A Multiscale Study of the Structure Evolution of the PM HIP Stainless Steels under Heat Treatment and Hot Deformation
(2022) Shulga, A. V.; Шульга, Андрей Васильевич
Только метаданные
A Multiscale Study Of Boron And Carbon Behavior In The Necking And Fracture Zones Of The High Temperature Ni-Based PM HIP Superalloy Under High Temperature Tensile Testing
(2022) Shulga, A. V.; Шульга, Андрей Васильевич
Только метаданные
"Anomalous particles (granules) in PREP-powders. A multiscale study of the PREP-powders and PM HIP compacts of the Ni-based superalloys and stainless steels"
(2020) Shulga, A. V.; Шульга, Андрей Васильевич
© European Powder Metallurgy Association (EPMA)Formation of the anomalous particles (granules) with the essentially different content of the microalloying interstitial elements carbon and boron is characterized for the composition uniformity of the rapidly quenched powder particles of the high temperature Ni-based superalloys and stainless steels produced by PREP-technique. A detailed multiscale experimental study of microstructure of the PREP-powders and PM HIP compacts of the Ni-based superalloys and stainless steels was performed with the aim to reveal the microstructure features of the anomalous granules in the as-received and consolidated state. The direct nuclear methods of activation autoradiography on carbon, track autoradiography on boron, metallography, SEM, EDX, and OIM were used. The essential effect of carbon and boron on the dendrite segregation of carbide- and boride-forming alloying elements in the anomalous granules was revealed. Features of carbon and boron behavior determine formation of the microstructure of anomalous granules and their retaining in PM HIP compacts were established.