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118 results on '"Petrakova, N. V."'

8. Structure of Al82Cu7Fe11 Alloy After High-Speed Quenching.

Author

Bakhteeva, N. D., Todorova, E. V., Umnov, P. P., Chueva, T. R., Gamurar, N. V., Petrakova, N. V., and Sviridova, T. A.

Abstract

Using structural analysis methods (metallographic, X-ray diffraction, differential scanning microscopy), a comprehensive study of the structure of Al82Cu7Fe11 alloy, obtained in the form of ribbons by the melt spinning method, was carried out. It is shown that a multiphase amorphous-nanocrystalline structure of high dispersity is formed in the alloy, which includes a solid solution based on aluminum, intermetallic compounds Fe4Al13 and CuAl2, and a small amount of a quasicrystalline phase of the composition Al–Fe–Cu with a tenth order symmetry axis (decagonal). The parameters of crystal lattices of phases and their volumetric content have been certified. It is shown that the main structural component of an alloy is iron aluminide, the content of which varies from 68 to 61 wt % across the ribbon cross section from the contact to the free surface. The temperatures of phase transformations in the alloy upon heating were determined. A comparative analysis of the structures on the basis of the phase composition and morphology of phases formed in rapidly quenched ribbons and an ingot of the same composition crystallized under equilibrium conditions was carried out. A difference in the alloy structure after different methods of crystallization has been established. The microhardness of the main structural components in the ingot was determined. Iron aluminide has a maximum hardness of 780 HV. It has been shown that the high hardness of 615 HV of the alloy after high-speed quenching is ensured by the formed multiphase amorphous-nanocrystalline state of the structure. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Structure of Al82Cu7Fe11Alloy After High-Speed Quenching

Author

Bakhteeva, N. D., Todorova, E. V., Umnov, P. P., Chueva, T. R., Gamurar, N. V., Petrakova, N. V., and Sviridova, T. A.

Abstract

Abstract: Using structural analysis methods (metallographic, X-ray diffraction, differential scanning microscopy), a comprehensive study of the structure of Al82Cu7Fe11alloy, obtained in the form of ribbons by the melt spinning method, was carried out. It is shown that a multiphase amorphous-nanocrystalline structure of high dispersity is formed in the alloy, which includes a solid solution based on aluminum, intermetallic compounds Fe4Al13and CuAl2, and a small amount of a quasicrystalline phase of the composition Al–Fe–Cu with a tenth order symmetry axis (decagonal). The parameters of crystal lattices of phases and their volumetric content have been certified. It is shown that the main structural component of an alloy is iron aluminide, the content of which varies from 68 to 61 wt % across the ribbon cross section from the contact to the free surface. The temperatures of phase transformations in the alloy upon heating were determined. A comparative analysis of the structures on the basis of the phase composition and morphology of phases formed in rapidly quenched ribbons and an ingot of the same composition crystallized under equilibrium conditions was carried out. A difference in the alloy structure after different methods of crystallization has been established. The microhardness of the main structural components in the ingot was determined. Iron aluminide has a maximum hardness of 780 HV. It has been shown that the high hardness of 615 HVof the alloy after high-speed quenching is ensured by the formed multiphase amorphous-nanocrystalline state of the structure.

Published
2024
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12. Hot pressed AlON ceramic.

Author

Lysenkov, A. S., Frolova, M. G., Kim, K. A., Petrakova, N. V., Ivicheva, S. N., Akhmadullina, N. S., Ovsyannikov, N. A., Melnikov, M. D., and Kargin, Yu. F.

Subjects
CERAMICS, SCANNING electron microscopy, X-ray microscopy, HOT pressing, ATMOSPHERIC nitrogen
Abstract

Monophase ceramics based on silicon oxonitride was obtained in one technological stage, combining the synthesis of the aluminum oxonitride phase and its further densification by hot pressing at 1850°C in a nitrogen atmosphere. The obtained samples were characterized by scanning electron microscopy and X-ray phase analysis; the mechanical properties of the ceramic samples were measured. [ABSTRACT FROM AUTHOR]

Published
2023
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13. Properties of ceramics SiC with sintering additive Al2O3-Y2O3-ZrO2.

Author

Lysenkov, A. S., Frolova, M. G., Perevislov, S. N., Kim, K. A., Petrakova, N. V., Kaplan, M. A., Melnikov, M. D., and Kargin, Yu. F.

Subjects
SINTERING, CERAMIC materials, STEREOLITHOGRAPHY, HOT pressing, THERMAL expansion, SILICON carbide, CERAMICS
Abstract

The effect of the Al2O3−Y2O3−ZrO2 sintering additive on compaction and mechanical properties of silicon carbide ceramics was studied in this work. The sintering additive was obtained by plasma-chemical synthesis. Sintering ceramic was carried out by hot pressing in the temperature range 1700-1800°C. With an increase in temperature, an increase in density and mechanical properties occurs. The ceramic material has a linear thermal expansion coefficient in the temperature range 20-1600°C equal to 3.9х10−6К−1. [ABSTRACT FROM AUTHOR]

Published
2023
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21. Interaction of SiC with Al2O3−(t + m)ZrO2(Y2O3) Oxide Composition.

Author

Frolova, M. G., Lysenkov, A. S., Perevislov, S. N., Petrakova, N. V., Kim, K. A., Sevost'yanov, M. A., Ivannikov, A. Yu., Mel'nikov, M. D., and Kargin, Yu. F.

Abstract

We employed contact alloying in the range 1000–1860°С to study the reaction specifics between SiC and Al2O3−(t + m)ZrO2(Y2O3) oxide composition. Real-time experiments with photographic recording of the changing size and shape of the Al2O3−(t + m)ZrO2(Y2O3) sample on a SiC ceramic substrate showed that Al2O3−(t + m)ZrO2(Y2O3) compositions react with the silicon carbide substrate in the range 1720–1860°С to melt and penetrate into (impregnate) the substrate. X-ray powder diffraction patterns were measured for samples taken from the contact area of the oxide composition with SiC directly on the substrate and in a chipped-off <1-mm-deep near-surface layer. ZrС, Al2Y4O9, and Al3.21Si0.47 were formed in the contact area via redox reactions involving oxide melt, in addition to 6H-SiC, Si and Al2O3, t-ZrO2 phases, which are the initial components of the substrate and oxide composition, respectively. [ABSTRACT FROM AUTHOR]

Published
2023
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25. Copper-substituted tricalcium phosphates

Author

Fadeeva, I. V., Gafurov, M. R., Filippov, Ya. Yu., Davydova, G. A., Savintseva, I. V., Fomin, A. S., Petrakova, N. V., Antonova, O. S., Akhmetov, L. I., Gabbasov, B. F., Izotov, V. V., Orlinsky, S. B., and Barinov, S. M.

Published
2016
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30. Effect of CaO–Al2O3 (48 : 52 wt %) Sintering Aids on the Phase Composition and Properties of Si3N4-Based Ceramics.

Author

Kim, K. A., Lysenkov, A. S., Fedorov, S. V., Petrakova, N. V., Frolova, M. G., Perevislov, S. N., and Kargin, Yu. F.

Subjects
CERAMIC powders, SINTERING, SILICON nitride, CERAMICS, HOT pressing, SCANNING electron microscopy
Abstract

Si3N4-based ceramics have been produced by hot pressing in the temperature range 1550–1650°C using α-Si3N4 starting powder and CaO–Al2O3 (48 : 52 wt %) sintering aids. The powders and the ceramics have been characterized by dilatometry, scanning electron microscopy, and X-ray diffraction, and we have measured the microhardness and density of the ceramic samples. The results demonstrate that the sintering aid reacted with Si3N4 to form Ca-α-SiAlON. At 40 wt % sintering aids, all of the silicon nitride was converted into Ca-α-SiAlON. We have clarified general trends in the effect of the amount of sintering aids on the properties of the ceramic samples. [ABSTRACT FROM AUTHOR]

Published
2022
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43. 21R-Sialon ceramics, obtained by hot pressing

Author

Lysenkov, A S, primary, Stolbova, M O, additional, Titov, D D, additional, Plokhikh, A I, additional, Kim, K A, additional, Gridin, D V, additional, Frolova, M G, additional, Petrakova, N V, additional, Danilin, K D, additional, Lemeshev, D O, additional, and Kargin, Yu F, additional

Published
2020
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47. Synthesis the composites Si3N4-TiN by hot pressing

Author

Kargin, Yu F, primary, Lysenkov, A S, additional, Kim, K A, additional, Ivannikov, A Yu, additional, Frolova, M G, additional, Titov, D D, additional, Ivicheva, S N, additional, Ovsyannikov, N A, additional, Konovalov, A A, additional, Perevislov, S N, additional, and Petrakova, N V, additional

Published
2019
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