Персона: Крымская, Ольга Александровна
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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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Крымская
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Ольга Александровна
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- ПубликацияТолько метаданныеEFFECT OF SUBSTRUCTURAL INHOMOGENEITY ON THE ANISOTROPY OF PHYSICAL AND MECHANICAL PROPERTIES OF TEXTURED MATERIALS(2022) Isaenkova, M. G.; Krymskaya, O. A.; Исаенкова, Маргарита Геннадьевна; Крымская, Ольга АлександровнаToday, anisotropy of the physical and mechanical properties of textured materials is mainly calculated based on average properties of a single crystal and information about the volume percent of grains that have different orientations, which can be determined with the help of distribution function. It is a fact that, in addition to the crystallographic texture, substructural inhomogeneity develops in rolled materials, which manifests itself as a difference in the distortion of the crystalline lattice (hardening) and elastic microstrains in grains belonging to different texture components. Substructural characterization is based on the X-ray method of Generalized Direct Pole Figures, which implies that a full profile of X-ray reflections is registered for different positions of the specimen, i.e. as a direct pole figure is being built. As a result, one can obtain the FWHMs of X-ray lines and elastic microstrains distributed on the stereographic projection. It means that a textured polycrystalline material that has undergone thermo-mechanical treatment is characterized with a certain spectrum of structural states and the presence of residual elastic microstrains. Therefore, the degree of macroscopic anisotropy of the product properties is defined both by the predominant grain orientation in the polycrystal and by the parameters of substructural inhomogeneity of grains belonging to different texture components. In spite of the fact that the elastic properties of an individual crystallite do not change and the tensile and compressive elastic microdeformations are balanced in the studied volume of the material, the elasticity of the whole system, i.e. of a polycrystal, changes due to interacting grains and the elastic energy stored in them. The authors propose a method for calculating elastic moduli and thermal expansion coefficients while accounting for the substructural inhomogeneity of the material by minimizing the elastic energy of the textured material. The efficiency of this method is demonstrated on specimens of a semi-finished channel pipe made of Zr – 2.5% Nb alloy. This research was funded by the Ministry of Science and Higher Education of the Russian Federation; Agreement No. 075-15-2021-1352. © 2022, Ore and Metals Publishing house. All rights reserved.
- ПубликацияТолько метаданныеSTRUCTURE, CRYSTALLOGRAPHIC TEXTURE AND ANISOTROPY OF PROPERTIES OF VZh159 ALLOY AND HOW THEY ARE INFLUENCED BY REGIMES OF SELECTIVE LASER MELTING AND FINAL HEAT TREATMENT(2022) Rubanov, A. E.; Isaenkova, M. G.; Krymskaya, O. A.; Yudin, A. V.; Исаенкова, Маргарита Геннадьевна; Крымская, Ольга АлександровнаThis paper examines the effect of scanning strategy (unidirectional scan, island scan and a scan with a 60° turn of the laser beam between layers) during selective laser melting and heat treatment on the crystallographic texture and mechanical properties of VZh159 alloy specimens. Application of different scanning strategies leads to two types of crystallographic texture formed in specimens: the axial component <100> gets reinforced in the unidirectional strategy, while it is the texture component {100}<001> in the other cases. After printing, the specimens were subjected to different regimes of heat treat-ment. They included quenching from 1,100° C; quenching from 1,100° C and ageing at 800 and 700° C; quenching from 1,100° C and ageing at 900, 800, 700 and 650° C. When heat treatment (ageing) tests are conducted at room temperature, it leads to increased yield point and strength as a result of se-condary phase precipitation at grain boundary and in grain core, while pla-sticity drops. During high temperature tests, no strength gain was found after heat treatment. In all heat treatment regimes, the authors observed anisotropy of mechanical properties in the specimens caused by the crystallographic texture that remains after heat treatment. The maximum strength and yield point were detected at 45° load application to growth direction during printing. At the same time, the anisotropy of yield point does not change during high temperature mechanical testing (at 850° C) and has no dependence on the amount of additional precipitates. It suggests that crystallographic texture plays a defi-ning role for anisotropy of properties. The research was conducted under financial support of Russian Federation presented by the RF Ministry of Science and Higher Education (Agreement No. 075-15-2021-1352). © 2022, Ore and Metals Publishing house. All rights reserved.
- ПубликацияТолько метаданныеCRYSTALLOGRAPHIC TEXTURE AND STRUCTURE FORMED IN ROLLED SHEETS OF ZIRCONIUM ALLOYS DURING ANNEALING(2022) Klyukova, K. E.; Isaenkova, M. G.; Krymskaya, O. A.; Fesenko, V. A.; Исаенкова, Маргарита Геннадьевна; Крымская, Ольга Александровна; Фесенко, Владимир АлександровичThis paper examines the processes of recrystallization in sheets of Zr – 2.5% Nb alloy rolled down to a 50–90% deformation and annealed at 610oC for 1, 3 and 5 hours. The heating rate varied from 10 to 100oC/min. With the help of X-ray structure and texture analysis, the authors looked at optimizing the crystal structure of the deformed alloy while examining changes in the crystallographic texture. It was established that annealing of Zr – 2.5% Nb alloy sheets performed at the temperature that corresponds to the dual phase region α + β of an equilibrium phase diagram also leads to recrystallization, as it happens when applying the annealing temperature of 580oC. However, an 11% increase in the concentration of the additional phase suppresses changes in the crystallographic texture, which may be due to the predominant precipitation of β-zirconium at grain boundaries. At the same time, the growth of recrystallized grains still follows the main regularities of orientation: the orientation of growing grains corresponds to the texture maximum slopes of the direct pole figure (0001); an increased pole density was observed on the difference charts of the direct pole figure (10.0), which is indicative of the presence of grains that are disoriented to the deformed matrix at 30o around the base normals. It is shown that the contribution of the above mentioned processes is determined by the type of initial texture, the annealing temperature, the heating rate and the amount of β-phase. An extended annealing time (from 1 to 5 hours) at the temperature of the dual phase region does not cause any significant change in the crystallographic texture.