Investigation the effect of machining conditions on the orientation of the crystal lattice of metals and alloys with cubic and hexagonal lattice

Целью выполняемой работы является изучение влияния режимов термической, механической и термомеханической обработок на ориентацию кристаллической решетки материалов при помощи современного оборудования установленного в Уральском федеральном университете. В работе проведено изучение, влияния режимов термической, механической и термомеханической обработок на образование вторых фаз, ориентацию кристаллической решетки материалов, методами растровой электронной микроскопии и дифракции обратнорассеяных электронов.The aim of the work is the study on the effect of thermal, mechanical and thermo-mechanical treatments on the orientation of the crystal materials lattice. In the paper the study on the effect of thermal, mechanical and thermo-mechanical treatments on the formation of secondary phases and the orientation of the crystal materials lattice by scanning electron microscopy and electron backscatter diffraction.Программа развития УрФУ на 2013 год (п.2.1.2.1

Effects of Sliding Velocity and Thermal Conduction of the Tool on X20Cr4 Steel Friction Coefficient and Structure in Nanostructuring Burnishing

The developmental study has succeeded in finding how the sliding velocity of an indenter affects the friction coefficient and changes the structure and phase state in the surface layer of a X20Cr13 stainless steel when nanostructuring burnishing is done with a tool with no heat removal and, alternatively, when the tool is equipped with a cooling system. It has been shown that structural dispersion of the treated material results in obtaining 20⋯80 nm nanocrystallites if the friction coefficient of the spherical synthetic diamond indenter is within 0.15⋯0.18 nm. Application of a compact cooling system, based on Peltier's thermoelectric module, made it possible to stabilize the friction coefficient at 0.17 and to increase the sliding velocity from 13 m/min, this being the case of no heat removal, to 45 m/min in the case when the cooling system having a cooling performance of 120 W was used. TEM and SEM analyses of the surface layer structure confirmed that there is a correlation between the friction coefficient and the size of nanocrystallites and the thickness of the dispersed layer. EBSD analysis of the structure showed that a maximum permissible sliding velocity can be established as referenced to the nucleation and growth of γ-phase grains in the nanostructured layer caused by heating of the material under deformation and reaching the temperature beyond the point α→γ phase transition as well as by behavior of dynamic recrystallization. It was established that the heat removal ensures suppression of dynamic recrystallization when the sliding velocity is increased up to 50 m/min. © 2018 Published under licence by IOP Publishing Ltd

Surface Texture of Deformed Copper Wire

The texture of the cold-drawn copper wire was investigated along the radius and on surface by means of EBSD. The wire fiber texture after drawing has been shown to consist of a set of a main orientations analogically to the rolling texture. These texture orientations are associated to the stress state in drawing. The central area of the wire was characterized by two main orientations: faint and powerful -fibers. Main orientations {110} and {112} were distinguished within these fibers. The peripheral region is represented by a shear texture that rotates 90 to the center texture and scattered at 10 . The surface texture scattered close to axial and also has deviated preferred components: strong {110} and weak {112} orientations. © Published under licence by IOP Publishing Ltd

Characterization of the matrix and fusion crust of the recent meteorite fall Ozerki L6

We studied the interior and the fusion crust of the recently recovered Ozerki L6 meteorite using optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy, X-ray diffraction (XRD), magnetization measurements, and Mossbauer spectroscopy. The phase composition of the interior and of the fusion crust was determined by means of SEM, XRD, and Mossbauer spectroscopy. The unit cell parameters for silicate crystals were evaluated from the X-ray diffractograms and were found the same for the interior and the fusion crust. Magnetization measurements revealed a decrease of the saturation magnetic moment in the fusion crust due to a decrease of Fe-Ni-Co alloy content. Both XRD and Mossbauer spectroscopy show the presence of magnesioferrite in the fusion crust. The temperatures of cation equilibrium distribution between the M1 and M2 sites in silicates calculated using the data obtained from XRD and Mossbauer spectroscopy appeared to be in a good consistency: 553 and 479 K for olivine and 1213 and 1202 K for orthopyroxene.Peer reviewe

Surface-dependent osteoblasts response to TiO2 nanotubes of different crystallinity

One of the major challenges of implantology is to design nanoscale modifications of titanium implant surfaces inducing osseointegration. The aim of this study was to investigate the behavior of rat osteoblasts cultured on anodized TiO2 nanotubes of different crystallinity (amorphous and anatase phase) up to 24 days. TiO2 nanotubes were fabricated on VT1–0 titanium foil via a two-step anodization at 20 V using NH4F as an electrolyte. Anatase-phase samples were prepared by heat treatment at 500 °C for 1 h. VT1–0 samples with flat surfaces were used as controls. Primary rat osteoblasts were seeded over experimental surfaces for several incubation times. Scanning electron microscopy (SEM) was used to analyze tested surfaces and cell morphology. Cell adhesion and proliferation were investigated by cell counting. Osteogenic differentiation of cells was evaluated by qPCR of runt-related transcription factor 2 (RUNX2), osteopontin (OPN), integrin binding sialoprotein (IBSP), alkaline phosphatase (ALP) and osteocalcin (OCN). Cell adhesion and proliferation, cell morphology and the expression of osteogenic markers were affected by TiO2 nanotube layered substrates of amorphous and anatase crystallinity. In comparison with flat titanium, along with increased cell adhesion and cell growth a large portion of osteoblasts grown on the both nanostructured surfaces exhibited an osteocyte-like morphology as early as 48 h of culture. Moreover, the expression of all tested osteogenic markers in cells cultured on amorphous and anatase TiO2 nanotubes was upregulated at least at one of the analyzed time points. To summarize, we demonstrated that amorphous and anodized TiO2 layered substrates are highly biocompatible with rat osteoblasts and that the surface modification with about 1500 nm length nanotubes of 35 ± 4 (amorphous phase) and 41 ± 8 nm (anatase phase) in diameter is sufficient to induce their osteogenic differentiation. Such results are significant to the engineering of coating strategies for orthopedic implants aimed to establish a more efficient bone to implant contact and enhance bone repair. © 2020 by the author. Licensee MDPI, Basel, Switzerland.Deutscher Akademischer Austauschdienst, DAADRussian Science Foundation, RSF: 18‐13‐00220Ministry of Education and Science of the Russian Federation, Minobrnauka: 57447934PPN/BEK/2018/1/00071Funding: The experimental work was funded by the Russian Science Foundation (grant no. 18‐13‐00220). This research was partially supported by DAAD together with the Ministry of Education and Science of the Russian Federation within Michael Lomonosov Program (project No. 57447934); M.W. was financially supported by the Polish National Agency for Academic Exchange (PPN/BEK/2018/1/00071)

Luminescence in anion-deficient hafnia nanotubes

Hafnia-based nanostructures and other high-k dielectrics are promising wide-gap materials for developing new opto- and nanoelectronics devices. They possess a unique combination of physical and chemical properties such as insensitivity to electrical and optical degradation, radiation damage stability, a high specific surface area, and an increased concentration of the appropriate active electron-hole centers. The present paper aims to investigate the structural, optical, and luminescent properties of anodized non-stoichiometric $HfO_2$ nanotubes. As-grown amorphous hafnia nanotubes and nanotubes annealed at 700{\deg}C with a monoclinic crystal lattice served as samples. It has been shown that the bandgap $E_g$ for direct allowed transitions amounts to $5.65\pm0.05$ eV for amorphous and $5.51\pm0.05$ eV for monoclinic nanotubes. For the first time, we have studied the features of the intrinsic cathodoluminescence and photoluminescence of the obtained nanotubular $HfO_2$ structures with an atomic deficiency in the anion sublattice at temperatures of 10 and 300 K. A broad emission band with a maximum of 2.3-2.4 eV has been revealed. We have also conducted an analysis of the kinetic dependencies of the observed photoluminescence for synthesized $HfO_2$ samples in the millisecond range at room temperature. It showed that there are several types of optically active capture and emission centers based on vacancy states in the $O_{3f}$ and $O_{4f}$ positions with different coordination numbers and a varied number of localized charge carriers ($V^0$, $V^-$, and $V^{2-}$). The uncovered regularities can be used to optimize the functional characteristics of developed-surface luminescent media based on nanotubular and nanoporous modifications of hafnia.Comment: 15 pages, 6 figures, 3 tables, 50 reference

Phase Transformation Crystallography in Pipeline HSLA Steel after TMCP

Thermo-mechanical controlled processing (TMCP) is employed to obtain the required level of mechanical properties of contemporary high-strength low-alloy (HSLA) steel plates utilized for gas and oil pipeline production. The strength, deformation behavior and resistance to the formation and propagation of running fractures of the pipeline steel are mainly determined by its microstructure and crystallographic texture. These are formed as a result of austenite deformation and consequent γ→α-transformation. This present study analyses the crystallographic regularities of the structural and textural state formation in a steel plate that has been industrially produced by means of TMCP. The values of the mechanical properties that have been measured in different directions demonstrate the significance of the crystallographic texture in the deformation and failure of steel products. An electron backscatter diffraction (EBSD) method and crystallographic analysis were utilized to establish the connection between the main texture components of the deformed austenite and α-phase orientations. This paper demonstrates that the crystallographic texture that is formed due to a multipath γ→α-transformation results from the α-phase nucleation on the special boundaries between grains with γ-phase orientations. The analysis of the spectra of the α-γ-interface boundary angle deviations from the Kurdjumov–Sachs (K–S), Nishiyama–Wassermann (N–W), and Greninger–Troiano (G–T) orientation relationships (ORs) allows to suggest that the observed austenite particles represent a secondary austenite (not retained) that precipitates at intercrystalline α-phase boundaries and correspond to the ORs with regard to only one adjacent crystallite. © 2023 by the authors.Ministry of Education and Science of the Russian Federation, MinobrnaukaThis research was funded by the Ministry of Science and Higher Education of the Russian Federation (Ural Federal University Program of Development within the Priority-2030 Program)

FORMATION OF RECRYSTALLIZATION TEXTURE IN A COPPER CAPILLARY TUBE

The texture state of copper capillary tube after cold drawing and annealing was studied by orientation microscopy. It is shown that in the process of recrystallization a texture is formed, the components of which are related with deformation ones by rotation about an axis at angles of 50°-70°.Работа выполнена при финансовой поддержке гранта Президента Российской Федерации (проект МК-5882.2021.4)

Laws of Formation Recrystallization Texture in the Wire of Technical Pure Aluminum

В ходе исследования было установлено текстурное состояние алюминиевой проволоки после деформации и рекристаллизационного отжига. Показано, что текстуру проволоки после деформации на локальном уровне можно рассматривать как текстуру, состоящую из дискретных компонент, соответствующих стабильным ориентировкам. Установлена взаимосвязь ориентировок деформации и рекристаллизации в предположении, что подвижными границами при рекристаллизации являются специальные границы, близкие к Σ3.During the study, the textural state of the aluminum wire after deformation and recrystallization annealing has been established. It is shown that the texture of the wire after deformation at the local level can be considered as consisting of discrete components corresponding to stable orientations. The relationship between the orientations of deformation and recrystallization is established on the assumption that special boundaries close to Σ3 are mobile during recrystallization.Работа выполнена при финансовой поддержке гранта Президента Российской Федерации (проект МК–5882.2021.4).The work was supported financially by a grant from the President of the Russian Federation (project MK–5882.2021.4)

THE DEFORMATION AND RECRYSTALLIZATION TEXTURE OF THE FCC METALS

На примере электротехнической чистой меди показано, что текстура волочения ГЦК-металлов представляет собой набор нескольких предпочтительных ориентаций, подобно текстуре прокатки. В периферийной области проволоки формируется текстура, близкая к текстуре сдвига, которая повернута относительно текстуры центральной области на угол несколько меньший, чем 90°. Распределение основных ориентаций по сечению деформированной проволоки связано с напряженно-деформированным состоянием, возникающим при волочении.In the case of electrolytic tough pitch copper wire, the drawing texture of FCC metals has been shown to consist of several preferred orientations, similar to the rolling texture. Texture similar to the shear one was formed in the periphery region, although it was rotated to the texture of central region at an angle slightly smaller than 90°. The distribution of the main preferred orientations along the cross section of deformed wire was explained with the stress-state occurring upon drawing in the central and periphery regions.Работа выполнена при поддержке Российского фонда фундаментальных исследований (грант 16-32-00030-мол_а)