In this study, modified surface layers on commercially pure fine-grained titanium were investigated after implantation with aluminum ions up to doses of 1 x 10(17) and 1 x 10(18) ions/cm(2). The main attention was paid to detailed examination of the surface layers similar to 2 mu m thick by transmission electron microscopy using the cross-section method. Implantation of aluminium ions refined grains in the titanium matrix and contributed to the formation of a gradient microstructure. In both cases, four sublayers were observed with different thicknesses. Enhancing the implantation dose did not affect the presence of sublayers but changed their thicknesses. In the modified layers, the Ti3Al and TiAl3 intermetallic phases were formed, the in-depth concentration of which varied. The patterns of the formation of the intermetallic compounds mainly depended on the grain sizes of the base metal, the implantation dose (the process duration), temperature and the residual pressure in a chamber. A comparison of the obtained data with the results of aluminium and titanium interdiffusion in the solid state showed that the thicknesses of the layers with the formed intermetallic compounds generally correlated despite the different processing conditions. However, no quantitative relationships were identified.

The paper presents research results of the evolution of dislocation structures in low-stability Cu–Mn alloys deformed at different temperatures. The dislocation structure evolution in these alloys indicates to an important process during a transfer from one deformation stage to another. Each stage is characterized by its own strain carrier in the form of the specific dislocation structure with the highest volume fraction at the given stage. The strain carrier from the preceded stage gradually dissapears at the given stage with increasing deformation, and the strain carrier from the successive stage appears. Thus, in a certain strain range, there are strain carriers from the preceded stage, given stage, and successive stage. It is supposed that the formation of the cellular structure corresponds to the kinetic diffuse first-order phase transition to the dislocation structure.

A physical concept of thermodynamic physical system states has been proposed with application to aqueous solutions at ultrahigh dilution that are low stable to external impacts. Based on the thermodynamic analogy of the solution states and the condensed physical system state, the feasibility of realization of low-stability states is demonstrated. An analysis of representations about thermodynamic and structural-phase states of water and estimations of the structure of aqueous solutions at ultrahigh dilution allow us to assume reasonably the feasibility of realization of low-stability structurally-phase states of aqueous solutions at ultrahigh dilution when the system goes into a new structural state under an external impact (mechanical shaking). Moreover, the external impact can be sufficiently small, but the structural system state can change quite significantly. It is discussed how the state of a suitable symmetric liquid solution of a substance, for which the effect of small impact of the external force in different forms (for example, shaking) is important, can be obtained experimentally. This approach allows the role of Epstein’s effect in shaking of chemical solutions to be estimated by mechanochemical methods.

The paper focuses on the evolution of the dislocation structure in Cu-Аl and Cu-Мn polycrystalline alloys in the low-stability state. Experiments conducted at different temperatures, show that the main structure of alloys having different content of Al and Mn alloying elements, changes insignificantly with increasing temperature in contrast to the density of dislocation barriers, dislocation clusters, dissociated dislocations, and stacking faults. Dislocation parameters of Cu-Mn alloys decrease with increasing temperature, while Cu-Al alloys manifest another behavior. The temperature effect on the dislocation structure parameters is different in Cu-Аl and Cu-Мn alloys. With increasing strain temperature, the average dislocation density in Cu-Mn alloys decreases, and grows in Cu-Al alloys. Misorientations in the structure, density of extinction contours and subboudaries reduce in Cu-Mn alloys and grow in Cu-Al alloys. It is found that the behavior of the dislocation structure parameters depends on temperature and is different in Cu-Аl and Cu-Мn alloys.

Using the methods of advanced materials science, the structural-phase states and properties of multiple plasma-surfaced layers of the R2M9U steel formed in a shielding-alloying nitrogen environment on the 30HGSA steel are studied after its subsequent triple high tempering. It is found out that a framework-type structure is formed in the surfaced layer, wherein the base element is iron and the atoms of Mo, N, Cr, and V are localized in lengthy interlayers of the skeletal network formed by the carbide phase of different compositions. The atoms of Al are concentrated in the globular particles chaotically distributed in the surface layer volume. Both in the layer surface and in the zone of its contact with the substrate there are microcracks located along the phase boundaries. After the triple high tempering, the framework material structure is retained. A significant increase (a factor of 1.4) in the surfaced layer microhardness is revealed, which is attributed to the formation of a martensitic structure in the grain bulk, implying substructural strengthening of the material. The tempering is accompanied by a decomposition of the solid solution, followed by the formation of submicron-sized second-phase particles, indicating a dispersion strengthening mechanism.

The paper presents results of transmission electron microscopy of the plasma coating/substrate interface. Its elemental and phase compositions and defect substructure are investigated. The high-speed steel R18-Yu coating is deposited in argon medium onto the type 30HGSA steel substrate high-tempered for several times. It is shown that both the coating and substrate are mutually alloyed. Primarily the substrate demonstrates a multi-phase, multi-element sub-nanoclystalline structure with the lamellar morphology. It is shown that multiple high-temperature tempering leads to the formation of carbide nanoparticles both in the volume and at the boundaries of the martensite lath structure.

The structure and microhardness of a multilayer surfaced on an R2M9 high-speed steel in a nitrogen atmosphere and subjected to high tempering and electron-beam treatment are studied. The surfaced layer structure consists of a tempered martensite, with the carbides and carbonitrides located along the grain boundaries. It is shown that high tempering increases the steel microhardness and gives rise to a transformation of the retained austenite into martensite. An electron-beam treatment forms a honeycomb structure in the surface layer, which provides a factor of 1.1–1.6 increase in the surface layer microhardness over the initial state and that after tempering.

Using the methods of advanced material physics, the structural-phase state of a layer of high-entropy high-speed non-equiatomic molybdenum tool steel formed by electric arc surfacing in a nitrogen atmosphere is studied. The thermodynamical and mechanical (elastic moduli) properties of the surfaced layer are examined in a temperature interval of 300–1400°C, and a phase-composition diagram is presented. It is observed that a temperature increase is accompanied by an α→γ polymorphic transformation, followed by a decrease in the content of carbide phases and elastic moduli.

Using the methods of advanced physical materials science, the structural-phase states and properties of an 80 μm-thick ribbon, made from a FeCoNiSiB high-entropy alloy of a non-equiatomic composition by ultrarapid quenching from melt, are studied. After the melt spinning the ribbon is in an X-ray amorphous state and demonstrates high strength and low plasticity. Anisotropy of its tribological properties is revealed. A differential scanning calorimetry of the ribbon is performed and its magnetic properties are evaluated.

Using the method of transmission electron microscopy (TEM) of thin foils, the nucleation and propagation of microcracks in various structures of the plastic zone in the polycrystalline low-stability copper–aluminum alloys are studied in the vicinity of their structural-phase transformation into a crack-bearing state. The evolution of misoriented dislocation substructures (DSSs), formed in the low-stability pre-transitional states in the vicinity of the cracking stability loss in the stage of developed plastic strain, is discussed. The relationship between the fine structure surrounding the microcracks and the dislocation substructure formed by the time of the material failure, i.e., the low-stability state of the material in the vicinity of its structural-phase transition into a into a crack-bearing state, is revealed. The principal factors, characterizing the dislocation density in these states of the material and the dislocation density in the substructures where microcracks nucleate, are identified. These factors are the misorientation boundaries of different origins and the long-range stress fields. The changes of the structure and the long-range stress fields are examined as a function of the distance from the microcracks and their tips.

The influence of alloying on the local structural features of the experimental samples is studied in the regions of their potential cracking in the low-stability states with an aim of revealing the regularities of cracking and fracture. It is found out that the microcrack density in the neighborhood of the fracture region in the Cu+5at.

The structural-phase sates and defect substructure are studied by the method of transmission electron microscopy using diffraction at different distances from the wheel–rail contact surface along the central axis of symmetry of the top of rail (TOR) (rolling surface) and along the radius of rounding (fluting) of the differentially hardened rails of the DH400RK category made of hypereutectoid steel after their continuous service. Using the obtained structure parameters, the estimates are made of the hardening mechanisms (strengthening by pearlite component, incoherent cementite particles, grain- and subgrain boundaries, dislocation substructure and internal stress fields) controlling the yield stress in the steel under study. A comparison is performed of the quantitative fine structure parameters and the contributions into hardening on the rolling surface and fluting. It is found out that the prevailing morphological component near the wheel– rail contact surface is the subgrain structure, and in the fluting – strengthening by incoherent particles.

Using the methods of scanning and transmission electron microscopy, the structural-phase states in the transition zone of a layer of fast-cutting S-2-9-2 steel (European standard) surfaced on 14331 medium-carbon steel (CSN standard) is investigated after tempering and electron-beam treatment. As a result of surfacing, a carbide network structure is formed, while there is no network in the transition zone. A plate-like martensitic structure is observed to form in the transition zone. The carbide phase particles measuring up to tens of nanometers demonstrate different morphology in the transition zone. They localize along the grain boundaries of martensitic crystals and austenitic interlayers and on dislocations in the bulk of the martensitic plates.

Recent publications of foreign and Russian researchers on the influence of niobium microalloying of pearlite steels and high-entropy alloys on their mechanical properties are briefly reviewed. The focus is made on the Nb effect on the microstructure and properties of rail steels and five-component (CoCrFeNiMn) Cantor alloys. The physical mechanisms of strengthening rail steels and high-entropy alloys are revealed and analyzed. An enhanced alloying effect in the case of a combined introduction of Nb + V and Nb + C into the high-entropy alloys is noted and interpreted.

The melt spinning technique is used to obtain non-equiatomic high-entropy alloy ribbon 80 μm thick. The X-ray phase analysis, scanning and transmission electron microscopies are used to study elemental and phase compositions and the defect substructure of the alloy ribbon.

Using the method of transmission electron microscopy (TEM) of thin foils, nucleation and propagation of microckracks are studied in different plastic zone structures. An interrelation between the fine structure around the microcracks and the types and parameters of the dislocation substructure formed by the point of fracture of the material, i.e. its low-stability state in the vicinity of a structural transformation into a state with cracks is found out. The main factors characterizing the dislocation density in the substructures are identified. These factors are the misorientation boundaries of various origins and long-range stress fields. The changes of the plastic zone structure and its parameters are examined from the mactrocrack and its tip inwards the material.

Based on post-processing of diurnal hourly measurements of three wind velocity components and their variances with an AV4000 minisodar in the lower 200-meter layer of the atmosphere, statistical analysis of the turbulent, ETКE, and average, EMКE, kinetic wind energy components has been performed. It was shown that for the diurnal period of continuous minisodar observations, the turbulent kinetic energy component in the ground atmospheric layer to altitudes of 50 m was low. At altitudes in the range from 50 to 100 m, the turbulent kinetic energy ETКE increased, at altitudes exceeding 100 m, its growth rate intensified, and the maximum ETКE values were observed at altitudes of 150–200 m. It was established that the results of observations influenced significantly by time of the day. However, at any time, the maximum turbulent energy was localized at altitudes of 100–200 m, which posed the greatest danger to light small-sized unmanned vehicles. The approach to revealing times and altitudes of maximum and minimum kinetic wind energy values from the minisodar data, that is, the most and least favorable time and altitude range for flights of light small-sized unmanned aerial vehicles has been proposed, and its efficiency has been illustrated.

Получены зависимости напряжения течения от деформации при разных температурах однородных твердых растворов на основе сплавов Cu–Mn с ГЦК кристаллической решеткой в зависимости от состава. Установлено, что различие между кривыми напряжения течения при разных температурах, растет с увеличением содержания Mn в сплаве. Представлены результаты исследования эволюции дислокационной структуры в сплавах Cu–Mn с содержанием марганца 1, 2, 4 и 6 ат. % в интервале размеров зерен 20…240 мкм при температурах деформации от 293 до 673 К методами дифракционной электронной микроскопии. Установлены зависимости скалярной плотности дислокаций от размера зерен и температуры испытания в сплавах Cu–Mn. Установлено, что с увеличением степени деформации происходит значительный рост средней скалярной плотности дислокаций. При фиксированной степени деформации во всех исследованных сплавах увеличение температуры деформации приводит к уменьшению плотности дислокации. В интервале размеров зерен от 10 до 100 мкм при всех температурах испытания наблюдается интенсивное уменьшение средней скалярной плотности дислокаций. Для размеров зерен свыше 100 мкм данная величина плотности дислокаций не изменяется. По микроснимкам, полученных в электронном микроскопе по ширине изгибных экстинкционных деформационных контуров измерялись численные значения кривизны-кручения кристаллической решетки. Установлено, что величина кривизны-кручения кристаллической решетке возрастает с деформацией нелинейным образом во всех исследованных сплавах. Величина кривизны-кручения кристаллической решетке при фиксированной степени деформации сплавах с размером зерна ~ 10 мкм больше, чем в сплавах с более высокими размерами зерен ~200 мкм.

The results of an electron microscopy study of the dislocation structure evolution in polycrystals of Cu–Mn homogeneous solid solutions having an fcc-lattice are presented. A scheme of the dislocation substructure rearrangements identified on the stress-strain curves in the transitions from one stage to another is constructed for the Cu–Mn alloys as a function of the concentration. A critical role of solid solution strengthening in the development of dislocation substructures (DSS) in the Cu–Mn alloys with an fcc crystal lattice is identified, which are the principal deformation carriers for a particular deformation stage. It is shown that the transitions from one DSS type to another occur in specific strain degree intervals ε. It is revealed that every deformation stage has its corresponding DSSs – deformation carriers. A stage-to-stage transition is followed by the formation of new deformation carriers, which is a characteristic feature of the low-stability states of this system.