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Aim. To develop an animal model of femoral head aseptic necrosis for studying Legg–Calvé–Perthes disease.Materials and Methods. To induce the development of aseptic necrosis, we used Wistar rats (n = 8) which suffered from combined hypoperfusion of the femoral head and increased intra-articular pressure in the hip joint. Having employed isoflurane anesthesia, we performed an incision (≈ 3 cm length) on the outer surface of the thigh in the projection of the hip joint and then excised periosteum in the proximal third of the femur. A dense vicryl ligature was applied around the femoral neck to reduce blood perfusion of the femoral head. Further, 1.5 mL 2% rheopolyglucinum solution (10% isotonic dextran, 30-40 kDa molecular weight) was injected into the hip joint cavity to increase intra-articular pressure. Rats were sacrificed upon 8-week follow-up with subsequent X-ray and histological examination.Results. Our animal model of femoral head aseptic necrosis includes two main components of Legg–Calvé–Perthes disease: an increase in the intra-articular pressure and insufficient blood perfusion of the femoral head. In all (8/8) cases, aseptic necrosis of the femoral head was achieved. Eight weeks post intervention, the condition of the proximal femur 8 was similar to impression fracture.Conclusion. Our model of femoral head aseptic necrosis fully reflects the pathogenesis of LeggCalve-Perthes disease and can be therefore used in experimental studies.

This work shows the results of research of the fine and dislocation structure of the transition layer of 18CrNi3Mo low-carbon steel after the influence of electrolytic plasma. Conducted research has shown that the modified steel layer, as a result of carbonitriding, was multiphase. Quantitative estimates were made for carbonitride М23(С,N)6 in various morphological components of α-martensite and on average by material in the transition layer of nitro-cemented steel. It was established that α-phase is tempered martensite after nitrocementation. Released martensite is represented by batch, or lath and lamellar low-temperature and high-temperature martensite. Inside the tempered martensitic crystals, lamellar cementite precipitates are simultaneously present, and residual austenite is found along the boundaries of the martensitic rails and plates of low-temperature martensite. It was determined that inside the crystals of all morphological components of α-martensite there are particles of carbonitride М23(С,N)6.

Transmission diffraction electron microscopy is used to study the evolution of a dislocation structure during active plastic deformation in copper–aluminum alloys in the 0–14 at % Al range of concentrations. Types of dislocation substructures are determined from micrographs, depending on the concentration of the alloying element. The parameters of the defect structure are measured and their relationship to stacking fault energy is established.

The paper investigates commercially pure titanium VT1-0 (US analog Grade 2) in the ultrafine grain state after the aluminum ion implantation at a fluence of 1∙1017, 5∙1017 and 10∙1017 ion/cm2. The investigation techniques include X-ray diffraction analysis, scanning electron microscopy with energy dispersive X-ray analysis, and transmission electron microscopy. Auger electron spectrometer is used to analyze the chemical composition of the implanted layer. The grain size in the longitudinal and transverse directions and the phase composition of ultrafine titanium are studied depending on the irradiation exposure. It is found that the ion implantation leads to the formation of such intermetallic compounds as Al3Ti and AlTi3 phases, β-phase titanium and aluminum oxide (Al2O3). The increased irradiation exposure results in the formation of a thicker implanted layer without changing its phase composition.

The paper studies the structure and phase composition of steel 0.12C–1Cr–1Mo–1V–Fe (grade DIN 14MoV63) after a long-term operation using the transmission electron microscopyю Investigated are the nontreated specimen (not subjected to operation) and specimens after a long-term operation with and without fracture. The phase composition and morphology of the steel structure are determined for each specimen. It is found that the steel servicing leads to the destruction of lamellar perlite, intensive fragmentation of ferrite, redistribution of the carbide component and elastic distortion of the crystal lattice.

The paper presents the transmission electron microscopy investigations of the structure and phase composition of ferritic-perlitic ST2 steel surface after electrolytic plasma quenching. The steel in the initial state represents the material after hardening at 890°С for 2 or 2.5 hours and quenching in warm (30–60°С) water with subsequent tempering at 580°C for 2.5 or 3 hours. Electrolytic plasma quenching is carried out at 850–900°С in an aqueous salt solution for 4 seconds, at 320 V voltage and 40 A current. In the initial state, the morphology of the steel matrix consists of lamellar perlite and nonfragmented and fragmented ferrite. Electrolytic plasma quenching of the steel surface results in the martensite transformation, steel self-tempering, and the formation of cementite particles in all martensite crystals. This treatment also leads to the diffusion transformation of γ → α phases, the release of residual austenite (γ -phase) along the low-temperature martensite laths and lamellas and in all crystals of lamellar martensite, the formation of М23С6 special carbides and, finally, to the enhancement of all parameters of the steel fine structure.

The paper presents the transmission electron microscopy investigations of the microstructure and phase composition of the nickel-based superalloy after high temperature annealing. All states of the superalloy are characterized by the single-crystal structure with [001] crystallographic orientation. The Ni–Al–Co alloy system also contains such elements as Mo, Cr, W, Ta, Re and Ru. The Ni–Al–Co system is studied in four states: initial (after directional crystallization) and after 1000°С annealing during 118, 372 and 1274 hours. The major phases forming the alloy system are γ- and γ′-phases. After annealing for 118 hours, the formation of Al6(Re, Ru) phase is observed. After longer high-temperature annealing new phases occur, such as σ-, δ- and Laves phase. The obtained alloy microstructure is classified into four types: 1) γ′-phase quasi-cuboids with γ-phase layers, 2) ribbon anisotropic microstructure of γ′+ γ-phase, 3) ribbon anisotropic microstructure with σ-phase particles in γ-phase layers, 4) γ-phase with δ-phase and Laves phase inclusions. The introduction of a large amount of various alloying elements and the annealing process modify the crystallographic texture of the superalloy.

The present study was conducted by transmission electron microscopy (TEM) in order to investigate the structure of multicomponent nickel-based alloy obtained by directional solidification and change in its phase composition at high-temperature annealing. All states of the alloy possessed monocrystalline structure with [001] orientation. The alloy under study contained other elements apart from Ni, such as: Al, Co, and also Mo, Cr, W, Ta, Re, and Ru. The alloy was investigated in three states after annealing for: 1) 118 h; 2) 372 h; 3) 1274 h at 1000°С. The basic phases that form the alloy were γ and γ′. In the state after annealing for 118 h Al6(Re,Ru) phase was observed in an insignificant amount. After longer high temperature annealing new phases occurred, such as σ-phase and δ-phase, Laves phase. The structures occurring during annealing can be classified into four types: 1) quasi-cuboids, 2) anisotropic stripe structures, 3) anisotropic structures of striped type with σ-phase separation, 4) structureless zones with large two-phase areas.

The present work summarizes and presents separate results obtained by the authors when investigating mesoscopic and microscopic internal stresses formed under the conditions of thermal and mechanical treatment of martensitic, pearlitic and austenitic steels. Internal stresses were investigated using the method based on the analysis of bend extinction contours. The results obtained on industrial steels were presented. The sources were described and examples of internal stresses induced by these sources were given. The nature of bending-torsion of the crystal lattice depending on the averaging volume was determined. It has been shown that in martensitic steels along with the increase in the averaging volume (carbide particle → separate martensitic lath → martensite packet→ martensitic plate → grain) the amplitude of bending-torsion of the crystal lattice decreases. The nature of distortions also changes. At large amplitudes and low volumes of averaging they are completely or partly elastic, at large volumes of averaging they are completely plastic. Thereby, distortions are fully driven by the excess dislocation density.

Using the transmission electron microscopy of thin foils the paper studies the phase composition and fine structure of 0.18С–1Cr–3Ni–1Mo–Fe steel after plasma electrolytic carbonitriding carried out through the surface saturation with nitrogen and carbon. The steel specimens are studied before and after carbonitriding on the surface and at a ~40 μm distance from the surface. It is found that carbonitriding causes significant qualitative and quantitative changes in the steel structure. Thus, the layers of residual austenite appear along the boundaries of martensitic lamellas, and the particles of alloyed cementite and carbonitrides are observed inside the lamellas. The layers of residual austenite locate at a ~40 μm depth along the boundaries of all martensitic crystals, while inside the crystals there are only particles of alloyed cementite and carbonitride M23(C, N)6. The control parameter of changes in the structure and phase composition is the concentration of interstitial atoms of carbon and nitrogen. Changes in this concentration lead to the system deviation from thermodynamic equilibrium. The transition of system to equilibrium or quasi-equilibrium states is considered to be performed through the transition of crystal lattices, which form a gradient structural-unstable state of the matrix, intermetallics and carbonitride compounds, to a low-stability state.

The paper presents the transmission electron microscopy (TEM) investigations of the thin film structure and phase composition of the heat-affected zone (HAZ) of a weld joint produced by manual metal arc welding (MMAW) of 0.12C–18Cr–10Ni–1Ti–Fe austenite steel exposed then to plastic deformation. The test machine INSTRON-1185 is used to perform quasi-static tensile tests at room temperature and a 1.7∙10–4 s–1 strain rate up to 5 and 37% deformations. TEM investigations are carried out within the HAZ, at a 1 mm distance to the weld line, in the direction of the parent metal and at 0.5 mm distance to the weld deposit. It is shown that MMAW results in the formation of e-martensite both in the parent metal and weld deposit regions. In the latter, γ → e phase transformation occurs faster. Plastic strain ranging between 0–5% throughout the HAZ leads to further γ → e phase transformation. In the weld deposit of the HAZ region, this phase transformation is also more intensive. Further increase in the degree of plastic strain from 5 to 37% results in γ → e → α phase transformation and an elastoplastic lattice distortion of the α-phase. The plastic flexure remains in the crystal lattice of the γ-phase. The bulk material in the HAZ region satisfies the following conditions: scalar dislocation density is higher than the excess, and internal shear stresses are higher than long-ranging.

Using transmission electron microscopy (TEM), phase composition and fine texture changes in the ferrite-pearlitic steels 0.18C–1Cr–3Ni–1Mo–Fe, 0.3C–1Cr–1Mn–1Si–Fe and 0.34C–1Cr–1Ni–1Mo–Fe due to electrolytic plasma nitrocarburizing has been studied in thin foils. The procedure of electrolytic-plasma enhanced nitrocarburizing has been performed by steel surface saturation with nitrogen and carbon in an aqueous solution at a temperature of 800–860°C for 5 min. All the steels under investigation have been studied before and after the nitrocarburizing procedure. In the initial state, the steels were discovered to be composed of a pearlitic and ferritic grain mixture. The nitrocarburizing procedure leads to the formation of modified layers. Thus, the greater is the amount of pearlite before nitrocarburizing, the thicker is the modified layer. Nitrocarburizing results in significant qualitative changes in the phase state and the steel structure. In the modified layer surface area alongside the matrix, the particles of other phases such as carbides, nitrides and carbonitrides occur. As the distance from the surface of a nitrocarburized sample increases, the phases of set and volume decrease, whereas the only carbide phase—cementite—occurs at the end of modified layer in the case of all the steels. After nitrocarburizing, the matrix of all the steels represents tempered lath and lamellar martensite. In the nitrocarburized layer surface zone, the volume fractions of lath and lamellar martensite depend on the initial steel state: the greater is the amount of pearlite in steel, the less is the amount of lath martensite; then a greater amount of lamellar martensite is formed. Such a dependence is not observed in the nitrocarburized layer central zone, whereas the volume fractions of lath and lamellar martensite at the end of the layer are close to each other.

The aim was to study the possibility of normalizing rhythmic brain activity and psychoemotional status in young patients with locally advanced cervical cancer after surgical castration and the development of severe postovariectomic syndrome using low dose xenon therapy regimens. Material and methods. The study included data obtained from 30 patients aged 39.4±3.7 years with cervical cancer pT1bN0M0 (n=14), pT2aN0M0 (n=16); after the extirpation of the uterus with appendages and the upper third of the vagina with pelvic lymphadenectomy, patients received low-dose xenon therapy in an exponential programmed regimen of xenon concentration and exposure. The state of brain rhythms was controlled using the electroencephalograph-recorder “En-cephalan EEGR-19/26”. 19 unipolar leads were recorded with the calculation of the EEG spectral power and topographical mapping using the Encephalan-3D program. Psychological testing of patients with cervical cancer was performed using the questionnaires of 7-point individual subjective self-assessment developed by Garkavi L.Kh.- KuzmenkoT.S. Results. The normalizing effect of xenon therapy involved restructuring of cortical brain activity with a decrease in the power of slow- and high-frequency alpha-rhythm subranges and the predominance of physiologically significant mid-frequency alpha rhythms of 9.6 Hz quiet wakefulness together with slow delta and theta ranges. This correlated with the data of topographic mapping of the power spectrum on the presence of two foci of the spatial organization of alpha and theta rhythms. Evaluation criteria for psychological testing showed the reduction of anxiety, depression, fatigue, normalization of sleep, appetite, work capacity, and increased activity and optimism in 82-98% of patients. Conclusion. The possibility of inhibiting the postcastration syndrome in patients with cervical cancer is evidently realized through the xenon-induced effect of brain rhythmogenesis restructuring, leading to the normalization of impaired cortical-subcortical relationships and the formation of positive psycho-emotional status. The therapeutic expediency of low-dose xenon therapy for oncogynecological patients is determined by a significant correction of the state of the CNS state and the early achievement of functional and social rehabilitation.

The paper presents research into the structure and phase composition of Ni–Al–Co alloy modified by rhenium (~3 аt.%) alloying. Observations are carried out using the transmission electron microscopy. The initial state of the alloy is the state after the directional crystallization. The alloy is further subjected to 900°С annealing during 1143 h. Creep tests are additionally carried out for this alloy at the same temperature and time and 400 MPa load. It is shown that FCC disordered γ- and ordered γ′-phases are major in all alloy states. Secondary phases are found to be σ-phase, χ-phase, Laves and AlRe2 phases. Experiments show that the high temperature annealing changes the phase composition of the alloy. Thus, the amount of the ordered γ′-phase increases, while that of disordered γ-phase decreases. During the creep process, the amount of the former reduces and the amount of the latter increases. The annealing process modifies the phase composition in secondary phases. It is found that the structural modification caused by the creep process differs from that caused by the annealing process. Thus, the creep-induced modification of the cuboid structure in γ′-phase is stronger than due to annealing. Dislocations are observed in γ- and γ′-phases in all states of the alloy. During the annealing process, the dislocation density in γ-phase is higher than in γ′-phase, and vice versa during the creep process. The experiments show that the behavior of the dislocation structures is different during the annealing and creep processes.

This paper presents scanning and transmission electron microscope investigations of the structure, phase composition, and morphology of a heat-resistant alloy modified by thermal treatment and additionally alloyed by rhenium. The rhenium alloy was obtained by using the directional crystallization technique. The structural investigations were carried out for two states of the alloy, i.e., (1) original (after the directional crystallization); (2) after the directional crystallization with 1150 °C annealing for 1 h and 1100 °C annealing for 480 h. It is shown that fcc-based γ- and γ′-phases are primary in all states of the alloy. The γ′-phase has an L12 structure, while γ-phase is a disordered phase. It was found that after directed crystallization, the volume fraction of the γ′ phase is ~85%, the fraction of the γ-phase is less than 10%. Annealing leads to an increase in the γ′- phase up to 90%, the proportion of the γ-phase practically does not change. Rhenium is a phase-formation element. The investigations show that high-temperature annealing modifies the structural and phase conditions of the heat-resistant alloy.

Transmission electron microscopy investigations were carried out to study the structural-phase state of ultra-fine grain (UFG) titanium with the average grain size of ~0.2 μm, implanted with aluminum ions. Implantation was carried out on MEVVA-V.RU ion source at room temperature, exposure time of 5.25 h and ion implantation dosage of 1⋅1018 ion/cm2. UFG-titanium was obtained by a combined multiple uniaxial compaction with rolling in grooved rolls and further annealing at 573 К for 1h. The specimens were investigated before and after implantation at a distance of 70-100 nm from the specimen surface. Concentration profile of aluminum implanted with α-Ti was obtained. It was revealed that the thickness of implanted layer was 200 nm, while maximum aluminum concentration was 70 at.%. Implantation of aluminum into titanium has resulted in formation of the whole number of phases having various crystal lattices, like β-Ti, TiAl3, Ti3Al, TiC and TiO2. The areas of their localization, the sizes, distribution density and volume fractions were determined. Grain distribution functions by their sizes were built, and the average grain size was defined. The paper investigates the influence of implantation on the grain anisotropy factor. It was revealed that implantation leads to the decrease in the average transverse and longitudinal grain size of α-Ti and decrease in the anisotropy factor by three times. The yield stress and contributions of separate strengthening mechanisms before and after implantation were calculated. The implantation has resulted in increase in the yield stress by two times.

Using the transmission electron microscopy technique, we have studied the structural-phase state of UFG titanium with an average grain size ~0.2 μm implanted with aluminum ions. An MEVVA-V.RU source has been used to implant the specimen at room temperature, implantation time 5.25 h, and irradiation dose 1 · 1018 ion/cm2. To produce the UFG titanium samples, we have employed the combined multiple uniaxial pressing technique (abc-pressing) followed by grooved rolling and subsequent annealing at 573 K for 1 h. The samples have been studied in two states: 1) before implantation (initial state) and 2) after implantation at a distance 70–100 nm from the sample surface. We have obtained the aluminum concentration profile of implanted α-Ti. It has been established that the maximum concentration of aluminum is 70 at.% and the thickness of the implanted layer is 200 nm. We have determined the grain distribution functions over the grain size, calculated the grain anisotropy coefficient before and after implantation. It has been established that implantation decreases the average longitudinal and transversal sizes of α-Ti grains, and reduces the anisotropy coefficient by three times. It has been established that aluminum implantation into titanium brings about formation of a whole set of phases with different crystal lattices, namely, β-Ti, TiAl3, Ti3Al, TiC, and TiO2.

In this paper, features of the dynamics of strain field distributions in both the 0.12% C–18% Cr–10% Ni–1% Ti austenite stainless steel plate and its GTAW butt joint under uniaxial tensile loads were investigated at the meso- and macroscale levels. It was detected by a Vic-3D digital optical system that the shift from one stage on stress–strain curves to another resulted in changes in the strain field distributions. The effect of strains on the structure and the phase composition was studied for the both base and weld metals at the microscopic level. It was found that the γ→e→α transformations had occurred in the weld metal and the heat-affected zone under the tensile loads.

The contributions of the mechanisms of strain hardening of differentially quenched rails are quantitatively analyzed as functions of the distance from the roll surface. The carbon distribution in the structure of rails after ground tests is studied. The main contribution to the hardening of rail steel is shown to be made by long-range stress fields and the dislocation substructure that forms during deformation. Substantial carbon redistribution is detected in rails during operation.

Previously, we identified a treatment regimen (“3+1”) to synchronize and eradicate solid and ascites forms of murine Krebs-2 tumor. Using a similar strategy, we attempted to narrow down the treatment conditions for mouse hepatocarcinoma G-29 that can be passaged in mice as either ascites or solid grafts. We successfully developed the protocol that allowed elimination of the primary ascites. Our results indicate that the “3+1” treatment protocol wherein the final doses of cyclophosphamide and double-stranded DNA preparation are given on days 6 or 11 had the greatest therapeutic effect. Mean survival time was 36 days in treated mice vs 27 days in untreated controls. We further demonstrate that tightly scheduled cyclophosphamide treatment was in itself highly inhibitory to the growing G-29 ascites. It has been shown that in the case of ascitic form of G-29 tumor after synergistic action of cytostatic and double-stranded DNA preparation, secondary ascites arises following the appearance of peritoneal carcinomatous solid formation and, apparently, is its derivative.

The properties of high-temperature nickel alloys for manufacturing depend on the thermal stability of the structure, the particle size, the shape, the quantity of strengthening γ' phase, and the strength of the γ solid solution. Such alloys are strengthened by the addition of rhenium and lanthanum. In the present work, the structure and phase composition of high-temperature nickel alloy with added rhenium (0.4 at %) and lanthanum (0.006 at %) are qualitatively and quantitatively investigated. The methods employed are transmission diffraction electron microscopy and scanning electron microscopy. The alloy structure is considered in three states: after directed crystallization (the initial state, sample 1); after directed crystallization, annealing at 1150°C for 1 h, and annealing at 1100°C for 480 h (sample 2); and after directed crystallization, annealing at 1150°C for 1 h, and annealing at 1100°C for 1430 h (sample 3). Primary and secondary phases are observed in the superalloy. The primary phases are γ' and γ. They form the structure of the alloy and are present in the form of γ' quasi-cuboids separated by γ layers. The secondary phases due to the presence of rhenium and lanthanum are β NiAl, AlRe, NiAl2Re, σ, χ, and Ni3La2. The secondary phases seriously disrupt the structure of the γ + γ' quasi-cuboids. The rhenium and lanthanum do not uniformly fill the whole alloy volume, but only appear in local sections. Therefore, in all three states of the alloy, only some volume of γ + γ' quasicuboids is disrupted. Analysis of the secondary phases’ morphology shows that the σ particles are thin needles, whereas the Ni3La2 particles have internal structure with characteristic contrast and are relatively thick. Interestingly, the σ phase and Ni3La2 are deposited at the same locations. The introduction of rhenium and lanthanum changes the phase composition of the alloy, suppressing the formation of γ phase. The particles of secondary phase are localized in individual sections of the alloy with specific periodicity. The secondary phases are refractory: the melting point is about 1600°C for β phase, 2600°C for σ phase; and 2800° for χ phase. Thanks to the formation of refractory secondary phases and their periodic distribution in the structure, the strength of the superalloy with added rhenium and lanthanum is increased.

The following problems are being solved within the framework of the “Long-Term Development Program of the Russian Coal Industry for the Period of up to 2030”: the modernization and renewal of coal production facilities and achieving the world standards of industrial security. The article is dedicated to the problems of evaluating the possibility of determining the stress-stained state (SSS) of the new elements of mining equipment in heat affected zones by acoustic and electron-microscope investigation.

The paper presents the results of the analysis of the microstructure, mechanical properties, acoustic and magnetic characteristics of the metal of pipelines that are part of heat and power equipment, after long-term operation, made of structural and heat-resistant steels in the zones of localization of plastic deformation. Samples of 0.2 C steel and 0.12C-1Cr-1Mo-1V steel were studied in the initial state, as well as after operation for 219 and 360 thousand hours, respectively. As a result of the studies carried out for each sample, the phase composition was determined (qualitatively and quantitatively), and the following parameters of the fine structure were calculated: volume fractions of structural components of steel (pearlite and ferrite), scalar ρ and excess ρ± dislocation density, curvature-torsion of the crystal lattice χ, amplitude of internal stresses (shear stress and long-range stresses). All quantitative parameters of the structure are determined both in each structural component of steel, and in general for each sample. The structure of the metal of all specimens after deformation before the formation of zones of stable localization of deformations consists of a ferrite-pearlite mixture, and for specimens after operation before fracture only of unfragmented and fragmented ferrite. Ferrite, which occupies the bulk of the material, is present both unfragmented and fragmented. For all samples, the ratios ρ ≥ ρ±, χ = χpl, σL ≥ σd were calculated, which indicate whether there is a danger of the initiation of microcracks in metal samples. For specimens without operation and after operation without damage in zones of stable localization of deformations, these conditions are met, and for specimens after operation until destruction, they are not met. It was found that the structural-phase state in the zones of localization of deformations has a direct effect on the characteristics of non-destructive tests. Thus, for all investigated samples, the values of such parameters as the delay time of the surface acoustic wave, the attenuation coefficient, the amplitude of the received signal, and the intensity of magnetic noise in the zones of deformation localization were established.

We report the study of commercially pure titanium (VТ1-0 alloy under Russian classification) in the submicrocrystalline state obtained by the abc-pressing method with the surface modified by the ion implantation technique. Ion implantation was performed using aluminum ions at irradiation doses 1 × 1017, 5 × 1017, and 10 × 1017 ion/cm2 using a MEVVA5.RU source. The grain longitudinal and transverse dimensions were determined before and after ion implantation for varying irradiation doses. We studied the influence of ion implantation and the irradiation dose on the elemental and phase composition of the surface layers of VT1-0 alloy. It has been found that ion implantation results in restructuring of titanium surface layers and in a change of the grain size with the depth of the surface layers. For example, the grain longitudinal size decreases 5 times at the dose rate of 1·1017 ion/cm2. It has been found that aluminum ion implantation modifies the surface layers containing intermetallic phases of TiAl3, Ti3Al, and aluminum and titanium oxides (Al2O3, TiO2, TiO и Ti2O3). Increasing the irradiation dose does not qualitatively change the alloy phase composition, but affects the quantitative characteristics of the formed secondary phases.

The paper presents the transmission and the scanning electron microscope investigations of the phase composition and fine structure of Ni–Al–Cr-based alloy alloyed by rhenium and lanthanum. The alloy is prepared by the directional crystallization technique and then subjected to 1150°С annealing during 1 hour. It is shown that γ- and γ′-phases are major and have a face-centered cubic crystal system. Solid solutions of γ- and γ′-phase have a disordered and an ordered atom arrangement, respectively. The latter has L12 superstructure. It is found that rhenium and lanthanum alloying leads to the structural modification of γ′-phase quasi-cuboids. Not dissolving in major phases, rhenium and lanthanum are phase-formation elements and form σ-phase. The phase composition and morphology of these phases are studied and described.

The effect of TiO2, ZrO2 and Na3AlF6 ultrafine powders on the fine structure and the phase composition of Fe–14Mn–1.2C steel was investigated. The introduction of the ultrafine powders into the melt influenced the grain size, the quantity, and the character of distribution of nonmetallic inclusions in the railroad frogs. The microstructure of castings was improved significantly because of the refinement of the grain structure and an increase of the grain-boundary area. After the modifying mixture was introduced into the melt, either the microtwins of one or two intersecting systems or the precipitations of ε-martensite of different types, or simultaneously the microtwins and wafers of ε-martensite, were present in each grain.

Alloy of the V-Ti-Cr system is a promising material exploited under high radiation and in corrosion environment. We sintered V-4.9Ti-4.8Cr alloy from particles with original average size of 30, 280 and 200 μm, respectively for vanadium, titanium and chromium powders, by pressing of the powder mixture and its further sintering. The studies were undertaken using the methods of X-ray structural analysis, scanning electron microscopy with an energy dispersive analyzer and transmission electron microscopy. It was established that the structure of the alloy represented matrix grains (BCC solid solution), along the boundaries and at junctions of which the groups of oxycarbonitride particles of V, Ti, Cr (C,N,O) type of the variable elemental composition were arranged. The particles possessed a plate-like (0.4 x 2.0 μm) and rounded (0.5 μm) shape. The solid solution of the alloy was heterogeneous by concentration. This was evidenced by the complications of the diffraction patterns obtained from the corresponding sections of the structure. These were cords of main reflexes, satellites and emergence of a moire banded contrast in separate sections of the sample. Inside the matrix grains, there were nanoparticles (15 μm) of carbide V55Cr25C20, being a source of elastic internal local stresses.

Transmission electron microscopy (TEM) investigations were carried out to study the structural-phase state of ultra-fine grained (UFG) titanium with the average grain size of ∼0.2 and 0.3 µm, implanted with aluminium ions. MEVVA-V.RU ion source was used for ion implantation under room temperature, exposure time of 5.25 h, at ion implantation dosage of 1×1018 ion/cm2. UFG-titanium was obtained by means of multiple uniaxial compacting with multipass rolling in grooved rolls and further annealing at 573 K during 1 hour to reach the average grain size of ∼0.2 µm, and annealing at 623 K during 1 hour to reach the size of ∼0.3 µm. The study revealed that in alloy with the average grain size of ∼0.2 µm implantation results in a decrease in longitudinal grain size of α-Ti (from 1.9 to 0.7 µm), however lateral size in its turn changed insignificantly (from 0.15 to 0.12 µm). Grain anisotropy factor decreased by 3 times. In the alloy with the average grain size of ∼0.3 µm both longitudinal and lateral grain sizes decreased (from 0.33 to 0.19 µm and from 2.1 to 0.8 µm correspondingly). The studies also showed that implantation of titanium with aluminium has led to the formation of a number of phases, such as: β-Ti, TiAl3, Ti3Al, TiC and TiO2. Their places of concentration, sizes, distribution density and volume ratios were determined. TiAl3 and Ti3Al phases were established to be ordered ones, formed within the conditions of ion exposure along the boundaries of α-Ti grains. Conducted calculations demonstrated that implantation contributed to the alloy strengthening, i.e. in alloy with the average grain size of ∼0.2 µm the value of yield stress increased by 2 times, and in the alloy with the average grain size of ∼0.3 µm—by 4 times.

This work deals with the study of changes in the dislocation structure and quantitative characteristics, as well as morphological components, of 0.34Cr-1Ni-Mo-Fe steel before and after plasma electrolytic hardening. According to the electron microscopic studies of the fine structure of 0.34Cr-1Ni-Mo-Fe steel before and after plasma electrolytic hardening, 0.34Cr-1Ni-Mo-Fe steel is a multiphase material containing an α-phase, a γ-phase (retained austenite), and a cementite and carbide phase. It was revealed that, morphologically, the α-phase in the initial state, generally, is present in the form of: lamellar pearlite with a volume fraction of 35%, a ferritocarbide mixture with a volume fraction of 45%, and fragmented ferrite with a volume fraction of 20% of the material. After surface hardening, the morphological components of the structure changed: packet–lamellar martensite with volume fractions of 60% and 40%, 5% and 7% of γ-phase as residual austenite in the crystals of packet–lamellar martensite, 0.6% and 1.5% of cementite in crystals of packet–lamellar martensite, and 0.15% and 0.35% of complex carbide М23С6 in crystals of packet–lamellar martensite, respectively, were observed. The quantitative characteristics of the dislocation structure were estimated by the following calculated indices of packet and lamellar martensite: scalar (ρ) and excess (ρ±) density of dislocations, the value of the curvature-torsion of the crystal lattice (χ), the amplitude of long-range internal stresses (σd), and the amplitude of shear stresses (σL), according to which the plastic nature of the bending-torsion of the crystal lattice was confirmed (σL &gt, σd).

The parameters of bend extinction contours are used to determine the tensor components of internal stresses, namely, the lattice bending and torsion stresses. The laws of their distribution and the contributions of the internal stresses to the plastic component during the deformation of an austenitic steel are found.

Processes that occur upon the straining of a polycrystal are studied. Components of the internal stress tensor were determined. Changes in the bending and torsion stresses in the crystal lattice of a strained polycrystal are analyzed. A correlation between changes in the internal stress tensor components and the fraction of material with complex bending is established.

The present paper investigates phase composition and fine structure of Ni-Al-Co-based alloy alloyed by Rhenium (Re) (~3 at.%), as well as studies preferred orientation of the given alloy primary phases by means of scanning electron microscopy and X-ray diffraction analysis. The original state was given as the alloy which underwent a complete cycle of heat treatment: stepwise homogenization, cooling, annealing, and cooling at 100°C/min back to room temperature. The alloy was further subject to annealing at 1000°C for 105 h and 968 h. It was also exposed to creep experiments at the same temperature for 105 h (loading 320 MPa), and for 968 h (220 MPa). γ- and γ′-phases were established to be the primary phases in both states of face-centered cubic crystal lattice. γ′-phase (phase with ordered atom arrangement having L12 superstructure) was the primary phase in all states of the alloy. Investigations showed that Re being able not to dissolve in the primary phases served as a phase-forming element. Phase composition and phase morphology were studied. The influence of high-temperature annealing and creep on superalloy structure and morphology of γ′-phase were defined. The influence of creep on the structure was proven to be different from the annealing effect. First, creep generated larger dissipation of orientations than annealing. Second, anisotropy of γ′-phase cuboids could be observed at meso-level. Cuboids partially joined together. Third, spheroidized cuboids could be often met after creep.

Using scanning and transmission electron microscopy, we studied silicon particles formed during the solidification of Al-7%Si alloy when different modifying mixtures were introduced into the melt: (1) a mixture of ultrafine powders Na3AlF6 + K2ZrF6 + TiO2 + ZrO2; (2) K2ZrF6; and (3) the flux Arsal. By differential scanning calorimetry, it was established that modifying mixtures significantly influenced the temperature of the solidification processes. The formation of two types of Si crystals was established. The first type of Si crystals precipitated during the solidification of the eutectic mixture (α-Al + Si) in the form of needles or plates. The second type of Si crystals was segregated from eutectic Al-phases or segregated from the solid phase α-Al upon cooling in the solid state. The introduction of modifiers led to a shift in solidification temperatures. When fluoride salts were used, there was an increase in the temperature of eutectic solidification. Silicon crystals were large (up to 10 µm), with a local excess of aluminum concentration.

Integrated assessment of the influence of an ultrafine mixture TiO2 + ZrO2 + Na3AlF6 on the formation of the structure, mechanical properties, and strengthening of ductile cast iron was made in the paper. The structural-phase composition of ductile cast iron was studied by means of scanning electron microscopy and a transmission electron microscope. Plastic deformation was determined during testing of uniaxial compression. The change in the structural state of the alloy and in its mechanical properties was observed. Quantitative assessment of contributions of separate physical mechanisms to strengthening characteristics of unmodified and modified ductile cast iron was made.

The results of study of stored energy density disttibution in deformed polycrystal austenitic steel are presented. The density of the stored energy is determined using bend extinction contours observed in electron microscopy images of the deformed steel. Patterns in the distribution of stored energy are established for grains with different types of bends.

The micromechanisms of plastic deformation of ultrafine-grained metallic materials are analyzed using copper, the nanostructure of which is produced by equal-channel angular pressing, as an example. Slip traces are studied at various deformation stages, and their parameters are estimated. The change in the granular structure during deformation has been studied.