The X-ray Rietveld method has been used to refine the structure, determine the lattice periods, and study the phase composition of the samples of multicomponent polycrystalline solid solutions TbCo _(2-x) Inx (х = 0, 0.05, 0.1, 0.15, 0.20, 0.25, 0.3, 0.35, 0.4), which are characterized by large values of magnetostriction saturation. With an increase in the indium concentration, the content of the TbCo2 phase with a Laves phase structure decreases, the content of the TbCo3 phase increases, and a Tb11Co4In9 phase is formed. The lattice period in the TbCo2 compound (sp. gr. Fd 3̅ m) changes nonlinearly: increases in the range of x = 0–0.1 from a = 7.209(8) Å to a = 7.216(1) Å due to the replacement of cobalt atoms with indium atoms, having a larger radius. Then, in the concentration range of x = 0.15–0.4, it decreases to a = 7.205(1) Å at х = 0.4 due to the replacement of terbium atoms with indium and formation of structural defects.

Abstract—The possibility of a conglomeration of elemental powders in the mechanical synthesis of a high-entropy 30Fe–30Cr–20Ni–10Mo–10W alloy has been determined. The distribution of particles of elemental powders in conglomerates formed during mechanical alloying has been studied. The influence of mechanical alloying modes on the content of conglomerates of a fraction of more than 32 μm in the powder charge is determined. The phase composition of the conglomerates after hydrogen heat treatment has been studied. The resulting conglomerates can be used in the process of additive manufacturing of parts of oil and gas equipment for operation in conditions of high temperatures and corrosive effects.

Effect of plastic deformation, heat treatment, and electron irradiation on the structural-phase state of Cu – 40 at. % Pd is studied. X-ray phase analysis of initial samples, samples obtained by rolling up to 0.2 mm, samples annealed after rolling in an argon atmosphere at 950 °C for 1 h, and samples irradiated by high-energy electron in air at temperature of 300 °C was carried out. A change in the phase composition of the samples after rolling was found: ~ 6 % of the ordered β-phase with bcc structure was formed, which disappears after annealing. As a result of irradiation, a layer of copper oxide CuO formed on the surface of the alloy, which under normal thermal conditions is formed at a temperatures of 400 – 500 °C, and the reflections of the ordered β-phase also disappeared in the near-surface layer. The elemental composition of the alloy changed in depth from the irradiated metal surface. Phases with a low degree of long-range order and an increased content of palladium were formed. The presence of these phases is due mainly to the selective oxidation of copper.

Abstract—Multicomponent polycrystalline TbInxCo2 – x (with х = 0–0.2) solid solutions are prepared for the first time, and their crystal structure and magnetic, magnetocaloric, and magnetostrictive properties are studied. X-ray diffraction patterns taken at room temperature demonstrate mainly the presence of the cubic C15 Laves phase in all samples. As the indium content increases to x = 0.1, the lattice parameter is found to increase; the further increase in the indium content to х = 0.2 leads to a decrease in the lattice parameter. In this case, the Curie temperature TC monotonically increases to 245 K. The isotheral magnetic entropy change ΔSmag is calculated in accordance with magnetic measurements using the thermodynamic Maxwell’s relation. At a magnetic field change from 0 to 1.8 T, the maximum entropy change monotonically decreases and, for composition with x = 0.2, is 1.8 J/(kg К). As the indium content increases to x = 0.05, the volume magnetostriction increases. The further increase in the indium concentration leads to the decrease in the peak values and their shift to high temperatures.

Four plasma cermet coatings with similar compositions based on TiC carbide and NiCrMo matrices with additional Cr3C2, WC carbides, and carbon were studied. The average oxygen content for four cermets increases from 0.51 % for powders to 0.86 % for coatings with a minimum plasma power and does not increase with its increase. The maximum average nitrogen content in the coatings, 0.34 %, is determined by the nitrogen content in the plasma. When spraying coatings, the loss of carbon, relative to the initial powder composition, is 2.79 – 3.76 %, less than in the manufacture of powders for spraying 4.3 – 6.6 %. Carbides Cr3C2, WC, matrix elements and the content of additional carbon determine the formation of the annular zone around TiC carbide, increase the total carbide content in the coating from 60 to 74 – 83% and the microhardness of the coating is 18 GPa with an indenter load of 200 gf.

The surface of monocrystalline silicon irradiated with a high-power pulsed beam of carbon ions and protons is studied using optical and scanning electron microscopy. The surface is irradiated using a TEMP-2 accelerator in a vacuum of 10–3 Pa. The ion beam consists of 70

Unsubstituted tricalcium phosphate (TCP) and Mn/Sr-cosubstituted TCP have been prepared by solid-state synthesis at 1200°C. The synthesized compounds have been characterized by X-ray diffraction, IR spectroscopy, and scanning electron microscopy. The results indicate that solid-state synthesis of TCP and Mn,Sr-TCP yields compounds with the whitlockite structure. We have determined their lattice parameters and demonstrated the incorporation of the manganese and strontium ions into the structure of TCP.

A study of the radiation-thermal resistance of ferritic steel 16Cr – 4Al – 2W – 0.3Ti – 0.3Y2O3 was made. This ODS (oxide dispersion strengthened) steel is perspective for fusion applications. The “Vikhr” Plasma Focus installation was used to introduse of powerful pulsed flows of helium ions and helium plasma. The power density of a beam of fast helium ions and high-temperature helium plasma flows was ~ 108 and 107 W/cm2 at exposure times of ~ 50 and 100 ns, respectively. The number of pulses N varied in the range from 10 to 30. The rate of evaporation and radiaсtive sputtering changed slightly with an increase in the number of pulses of energy flows acting on the material and amounted to h ≈ 0.01 – 0.02 μm/puls. The irradiated surface after repeated melting under the action of a pulsed radiation-thermal load with powerful energy flows acquired a wave-like character with inclusions of dispersed micro particles of the second phase, containing mainly yttrium, oxygen, aluminum, iron, and titanium. At the same time, in contrast to the refractory metals (W, Mo, Ti) earlier under similar radiation conditions studied, no micro- and macro cracks were formed on the surface of the material facing the plasma. “Vikhr” Plasma Focus setup proved to be an effective tool for simulation testing of candidate materials with magnetic and inertial plasma confinement.

The surface of single-crystal silicon irradiated with a powerful pulsed beam of carbon ions and protons was studied using optical and scanning electron microscopy. The surface was irradiated using a TEMP-2 accelerator in a vacuum of ~10–3 Pa. The ion beam consisted of 70 % carbon ions (C+ + C+2) and 30 % protons. The sample was irradiated with one pulse with a dose of 1.5 × 1013 ions/cm2. Craters characterized by a hexagonal shape were obtained on the silicon surface. X-ray phase analysis showed the presence of carbon content inside the crater.

Твердофазным синтезом при 1200°С получены трикальцийфосфат и Mn,Sr-замещенный трикальцийфосфат (ТКФ). Синтезированные соединения охарактеризованы методами РФА, ИК-спектроскопии, СЭМ. Показано, что в результате твердофазного синтеза ТКФ и Mn,Sr-ТКФ формируются соединения со структурой витлокита. Определены параметры кристаллической решетки и установлен факт внедрения ионов марганца и стронция в структуру ТКФ.

A quantitative texture study of the tooth enamel, with construction and analysis of the orientation distribution function reconstructed from direct pole figures, has been performed by the series expansion method with regularization of solutions. It is found that the healthy tooth enamel is formed by hydroxyapatite with the chemical formula Ca 10 (PO 4 ) 6 ((CO 3 ) 0.75 (OH) 0.5 ), which has a fairly sharp basal texture. During the enamel destruction the hydroxyapatite texture changes, becoming more diffuse.

The structure, phase composition, mechanical and magnetic properties of deformable hard magnetic Fe–30Cr–20Co–2Mo alloy obtained by sintering (1400°C, 240 min) of elemental powder compacts. The effect of quenching (1300°C, water) and stepwise heat treatment on the structure, mechanical properties during compression and magnetic characteristics of the samples is established. In the samples after sintering, a high proportion of the brittle sigma phase is recorded ( 47

The possibility of conglomeration of elemental powders in the mechanical synthesis of a high-entropy 30 Fe – 30 Cr – 20 Ni – 10 Mo – 10 W alloy has been determined. The distribution of particles of elemental powders in conglomerates formed during mechanical alloying has been studied. The influence of mechanical alloying modes on the content of conglomerates of a fraction of more than 32 microns in the powder charge is determined. The phase composition of conglomerates after hydrogen heat treatment has been studied. The resulting conglomerates can be used in the process of additive cultivation of oil and gas equipment parts for operation at high temperatures and corrosive effects.

The magnetron spraying method is used to obtain nano- and microscale surface layers of tantalum deposited on wire and on flat NiTi substrates. The structure and composition of layers are determined using scanning electron microscopy and Auger spectroscopy. With increase in the spraying time, the thickness of the surface layer grows nonlinearly, which leads to a change in X-ray contrast of the material relative to the substrate. On the basis of calculations of the linear attenuation coefficient for X-ray radiation, it is demonstrated that layered composites in the form of a plate having a surface layer on one side can be conditionally represented as a multicomponent monolith. When the sample is rounded, the continuous surface layer surrounding it from all sides has a greater effect on X-ray contrast.

The results of studying the effects of pulsed flows of helium ions (HI) and helium plasmas (HP) on the Inconel 718 alloy prepared by additive technology by selective laser melting followed by heat treatment are presented. The main structural changes in the irradiated surface layer (SL) are determined for two modes of irradiation - soft (with radiation power density q = 2 ∙108 W/cm2 at pulse duration τ = 50 ns) and hard (at q = 1.5 ∙109 W/cm2, τ = 25 ns). The number of pulsed actions in each mode was N = 10 and 20. It has been found that in the initial state and after irradiation, the alloy under study is a single-phase nickel-based solid solution with an fcc lattice. The impact on the alloy of pulsed HI and HP flows leads to a change in the initial texture in the 220 direction to texture 111. This change in the texture favored the occurrence of the plastic deformation (PD) process observed in the irradiated SL, during which in metals with an fcc lattice, under the action of applied thermal stresses, slip occurs predominantly along the {111} planes. The influence of the irradiation mode of the investigated alloy on the parameter of its crystal lattice is noted. In the soft mode of exposure to HI and HP flows, the lattice parameter a decreases compared to the initial value, which may be due to the action of residual macrostresses, as well as to the evaporation of atoms of impurity elements located in lattice interstices from the SL. In the hard irradiation regime, the parameter a increases, which is due to the dominant influence of the mechanism of implantation of helium ions into the alloy, which contributes to the increase in the value of a. It have been shown that the observed structural changes in the SL of the alloy lead to a decrease in microhardness and softening of the remelted layer. The role of thermal and shock-wave effects in the processes of PD and structural changes in SL under the implemented irradiation conditions was estimated by numerical simulation.

Nano- and microdimensional tantalum surface layers were created on wire and flat NiTi substrates by magnetron sputtering. The samples structure and composition were determined using SEM and Auger spectroscopy. As the sputtering time increases, the thickness of the surface layer increases non-linearly, which leads to a change in the radiopacity of the material relative to the substrate. Based on the calculations of the coefficient of linear attenuation of X-ray radiation, it is shown that a layered composite in the form of a plate with a surface layer on only one side can be conditionally represented as a multicomponent monolith, but with a rounded sample section, a continuous surface layer surrounding it from all sides has a greater effect on radiopacity.

The growing interest of developers of magnetic systems in strands based on the Nb3Sn superconducting compound with a high critical current density in magnetic fields above 12 T leads to the need to test various combinations of alloying elements in the superconducting layer. It also requires study of their effect on the microstructure and properties of this layer. Titanium and tantalum are the most commonly used alloying elements in the production of Nb3Sn-based superconductors. The effects of each of these elements on the electrical properties of Nb3Sn have been studied for many years. However, many questions remain about the combined effects of these elements. We study the features of the microstructure of two Nb3Sn-based strands with a diameter of 1 mm, which have the same design and titanium content, but with different tantalum contents: 4.0 and 7.5 wt %.

Five cermet coatings based on carbides 45TiC – 10Cr3C2 – 5WC with different contents of additional carbon were formed by plasma spraying with local protection: 0; 1.4; 2 and 2.8 %. In four cermets, the matrix was based on Ni – 20Cr. In one cermet, the alloy used was 38.5Co – 32Ni – 21Cr – 8Al – 0.5Y. All matrices were additionally introduced Mo. Powders for spraying were obtained by crushing cakes. In the particles of the obtained powders, carbides are distributed relatively uniformly; in coatings, this is noticeable to a lesser extent. After liquid-phase sintering, WC and Mo are not fixed in cermets; part of the Cr3C2 carbide passes to another structural state. The initial carbides in the cake and coating partially dissolve and, upon solidification and together with matrix elements and additional carbon, form an annular zone around the initial TiC carbide, decreasing its lattice period, X-ray fixes TiMoC2 carbide, the content of which is higher than the content of TiC carbide in the initial mixture. The content of the initial carbides in the coatings, measured by optical microscopy, decreases from 71 vol.% In the powder to 48 vol.% At the minimum plasma power and up to 36 vol.% At the maximum power. The average total TiMoC2 content of carbides in coatings according to x-ray data for four cermets is 76 %, higher than their content in spraying powders, 72 %, due to higher spray hardening rates. The average microhardness for all coatings is 22.01 GPa with an indenter load of 20 gf, which is lower than the average microhardness for all powders, 23.51 GPa. With an indenter load of 200 gf, the average microhardness for all coatings of 15.88 GPa corresponds to the average microhardness for all powders, 15.17 GPa.

The changes in the mechanical properties and the texture of the surface layers in Cu–10Ga and Cu–10Ga–4Ni alloys are studied under the powerful pulsed radiation-thermal and shock-wave loads characteristic of pulsed thermonuclear fusion plants. Samples are irradiated by pulsed high-temperature plasma and ions in the 600-kJ Plasma Focus (PF) PF-1000 (Poland) plant, and deuterium is used as a working gas. The deuterium plasma power density is varied from 107 to 109 W/cm2 at the plasma pulse duration of ~10–7 s, and the deuterium ion flux power density is from 108 to 1011 W/cm2 at an ion flux incident time of ~5 × 10–8 s. Irradiation under the experimental conditions is found to change the texture of the surface layers to a depth of several micrometers, which is likely to be caused by directional solidification at a high temperature gradient oriented normal to the irradiated sample surface. There is a correlation between the type of texture formed in this case and the character of propagating slip lines with formation of a block structure. The lattice parameter in the irradiated surface layers decreases, which is related, supposedly, with the action of residual macroscopic stresses, since substantial changes in the surface layer composition have not been observed. A general tendency toward a decrease in the Vickers microhardness is noted in copper alloy samples as a result of their irradiation in the PF plant under the experimental conditions. A possible cause is thermal effect, since the concentration of alloying elements in the alloys decreases insignificantly after irradiation. The elastic modulus E of the Cu–10Ga alloy decreases insignificantly (to 14%) after irradiation. At the same time, in the Cu–10Ga–4Ni alloy, i.e., after alloying of the Cu–10Ga alloy with nickel (element with higher E as compared to that of copper), the elastic modulus of the initial surface layer remains almost the same after irradiation in PF.

The surface effects and the damage and structural changes in the titanium surface layer (SL) during irradiation with powerful pulsed helium ion (HI) and helium plasma (HP) fluxes are investigated. Experiments are carried out in the Vikhr Plasma Focus (PF) plant at the radiation power density of ions qi ≈ (1–5) × 108 and plasma qp ≈ 107 W/cm2 and pulse durations τi ≈ 30–50 and τp ≈ 50–100 ns, respectively. A wavy surface forms due to melting and erosion during irradiation of the titanium SL. The microstructure of the irradiated layers does not contain microcracks and blisters observed under similar irradiation conditions in niobium, austenitic and ferritic steel, tungsten, and vanadium when deuterium or hydrogen is used as a working gas. The effect of HI and HP fluxes on titanium causes structural changes in the irradiated SL. A lamellar structure similar to a martensitic one forms in α-Ti grains. The initial SL texture corresponding to a rolling one transforms into a solidification texture. The lattice parameter of titanium and the coherent scattering domain sizes decrease with increasing structural microstrain. These structural changes are related to high-rate solidification of the molten SL, implantation of high-energy HI into the material, and thermomechanical stresses occurring in a target sample at the cooling stage. The structural changes tend to become more pronounced as the number of pulses increases.