In this study, composite coatings reinforced with boride particles were synthesized on titanium substrates. In this way, both LaB6 and Ti thin films were deposited alternatively with subsequent low-energy high-current electron beam (LEHCEB) processing in a single vacuum cycle. The film thicknesses were selected so that the boron and titanium contents were close to the composition of the TiB2 compound. Upon LEHCEB processing, the effect of energy densities on the microstructures, both chemical and phase compositions, as well as wear resistance of the coatings was considered. It was found that they could comprise mixtures of predominantly TiB2 nanoparticles distributed in the submicrocrystalline titanium matrix at an energy density of 3.5 J/cm2. In this case, wear resistance of the coating significantly exceeded those of the titanium substrate. Increasing the energy density up to 4.5 and 5.5 J/cm2 promoted additional melting of the substrates and dilution of the molten films with titanium from them, reducing the proportions of boron in the coatings. These changes in their chemical compositions led to variations in the observed phases. In addition, the excessive heat input caused the formation of surface discontinuities, deteriorating wear resistance.

The paper deals with the direct synthesis of titanum borides from lanthanum hexaboride layers deposited onto a titanium substrate followed by processing with a microsecond low-energy high-current electron beam (LEHCEB). It is shown how the electron-beam energy density affects the structure and properties of the obtained surface layer. The latter consists of 54 to 41 at.

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.

For the first time, the synchrotron X‑ray diffraction is used to study the phase evolution in the Fe-Cr-Al(film)/Zr(substrate) system during its low-energy high-current electron beam (LEHCEB) processing. It is found that surface layer undergoes successive phase transformations with increasing number of pulses and the energy density of LEHCEB. Initially, only Fe-Cr-Al film melting occurs. Next, the gradual film dissolution and the amorphous Fe-Cr-Al-Zr phase formation takes place, followed by the nucleation and growth of FeZr2 intermetallic compound. And finally, the formation the β‑Zr solid solution phase occurs. During the interruption of the LEHCEB process at different stages, it is possible to achieve desired phase composition and surface layer properties.

The review summarizes the progress achieved in the surface modification of NiTi shape memory alloys (SMAs) with laser and electron beams in terms of their compliance with the requirements for biomedical devices and implants. The main provisions of the standards regulating this area of activity are aggregated. The production routes for manufacturing bulk items from NiTi SMAs are described. Since the formation of surface alloys on NiTi SMAs is now an intensively growing area of research, the influence of additional alloying elements on their functional properties is also discussed. The common patterns of interaction of laser and electron radiation with NiTi SMAs are specified. The typical requirements for surface layer conditions and conventional methods for their modification are reported. The results of various laser processing methods, differing in energy parameters, atmospheres and beam scanning algorithms, are summarized. They include remelting, annealing, nitriding, shock peening, alloying and texturing. In addition, some data on the modification and alloying of the surface layers with high-current pulsed electron beams are integrated. Finally, the aggregated information is compared and analyzed from the point of view of its prospects in these research areas.

In this study, W-Zr surface alloys (SAs) were synthesized by low-energy high-current electron beam (LEHCEB) processing of preliminary deposited tungsten films on zirconium substrates in a single vacuum cycle. Then, their microstructure, as well as both chemical and phase compositions were investigated. Also, computer simulation of the dynamics of temperature fields was carried out. After LEHCEB processing of the Zr substrate with the pre-liminary deposited W film, the constituent element distributions were non-uniform over the surface of the W-Zr SA at the energy density of 3.5 J/cm2. Rising the energy density up to 5.5 J/cm2 resulted in a smoother and more homogeneous W-Zr SA. At the energy density of 3.5 J/cm2, the average tungsten content over the surface was 53 +/- 39 at.%, while it was only 26 +/- 2 at.% at 5.5 J/cm2. All W-Zr SAs consisted of the W phase (in different proportions), tungsten-rich solid solutions in the stabilized beta-Zr phase, and the W2Zr intermetallic compound. The contents of the beta-Zr and W2Zr phases enhanced with rising the energy density due to a greater amount of dissolved tungsten. Based on the obtained results, a scheme was proposed describing the formation of the SAs upon LEHCEB processing.

The present work deals with the chemical constitution of coatings deposited by plasma activation of hexamethyldisiloxane in positive column plasma of a low-pressure DC glow discharge in an argon flow (mass flow rate 230 mg/min). X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) are used to analyze deposit chemistry. The substance is complex and consists of many constitutional units forming branched and cross-linked irregular macromolecules. Chemical constitution depends on both discharge current (10-60 mA) and monomer flow rate (1-10 mg/min). Using the specific energy (SE) and Arrhenius-like approach, the threshold energy for the plasma polymerization of HMDSO has been estimated to be 12 +/- 1 eV. Two regimes of the plasma chemical system have been identified. At SE near the threshold energy (from 5 to 40 eV/molecule), polymethylsiloxane-like coatings are deposited and variation of SE practically does not lead to changes in chemical constitution, but significantly affects the mass yield of deposit. At specific energies much higher than threshold energy, polymethylhydroxysiloxane-like coatings are formed; the coating structure is strongly SE-dependent, while the mass yield of the deposit does not change.

Lasers and electron beams have been widely used to synthesize various surface alloys (SAs) but no data have been reported so far on the molybdenum-zirconium (Mo-Zr) ones. To partially fill this knowledge gap, Mo-Zr SAs were formed by processing molybdenum films on zirconium substrates with low-energy high-current electron beams (LEHCEBs). The effect of the energy density of LEHCEBs on the microstructure, phase composition, nanohardness and corrosion resistance of the Mo-Zr SAs were investigated. Basically, the Mo-Zr SAs consisted of a solid solution of Mo in the beta-Zr phase, Mo2Zr second phase particles (SPPs) and a solid solution Zr in Mo. Increasing in the energy density decreased the concentration of the SPPs and enhanced the content of the beta-Zr phase. Also, it affected the depth of the highest concentration of the SPPs. In the zones of the highest molybdenum contents, the nanohardness values reached 9.4-12.7 GPa, which was higher by 3.2-4.4 times than that of the zirconium substrates. In a 3.5 % NaCl solution at room temperature, the corrosion current densities and the corrosion potentials were greater than those of the zirconium substrates by six and almost two times, respectively.

In this paper, we report our findings on the preparation of a film/alloy/substrate system with the use of a low-energy high-current electron beam (LEHCEB), as a result of sequential growth of molybdenum and chromium films on a zirconium substrate by magnetron sputtering. The system was produced in a single vacuum cycle, by cyclic growth of molybdenum film on a substrate and LEHCEB irradiation, followed by chromium film growth as a final step. We demonstrate that LEHCEB irradiation leads to the formation of Mo–Zr alloy consisting mainly of the high-temperature phase β-Zr. The alloy has the form of a layer 4.2 ± 0.9 μm in thickness, containing molybdenum-enriched regions. Such regions result from the formation of secondary phases: intermetallic compound Mo2Zr and a solid solution of Zr in Mo.

The review summarizes high-energy processing techniques applied for additive manufacturing and surface engineering of cemented carbides and cermets, including laser, electron, and ion beams, as well as plasma and electric discharges. The motivation for writing the review has been the fact that numerous papers have been published in these areas of science, but prospects for such studies in terms of their industrial implementations are unclear at present. In this way, the authors' goal has been to report achievements, challenges and gaps in knowledge for a more meaningful drawing of further research roadmaps. The review includes classifications of up-to-date cemented carbides and cermets in accordance with their compositions, fabrication methods, microstructure, functional properties and typical operating conditions. Then, some patterns of the evaluation of their microstructure and key characteristics are summarized. After that, achievements and challenges of laser and electron-beam additive manufacturing procedures are overviewed. Another topical section is devoted to surface engineering by both conventional methods and high-energy processing procedures. The authors have concluded that the key challenges are difficulties in simultaneous processing of both hard and binder phases without deteriorating their properties in the formed composites, as well as great residual stresses, causing the formation of cracks. To solve these issues, computer simulation methods, implemented for additive manufacturing and surface processing of metallic products, should be adapted for such composite materials. Also, a comparative economic evaluation of the return on investment in such innovative processes should be done for focusing on promising research directions.

The effect of ion- or electron-beam treatment on the structure and residual stresses formed in the surface layers of the Ta-doped TiNi alloy was revealed. The ion-beam treatment leads to the formation of a thin amorphous surface layer. An ion-beam treated sample does not exhibit residual stresses of the 1 st kind, but possesses a low level of residual stresses of the 2 nd kind. Surface alloy synthesis via an electron-beam melting of the Ti 60 Ta 40 (at.%)/TiNi system leads to the formation of the outer crystalline layer, amorphous sublayer, and large residual stresses localized in the heat-affected zone.

The effect of film material thermal conductivity on the melting threshold of the film-substrate system depending on the film thickness during a low-energy high-current electron beam (LEHCEB) irradiation is analyzed based on the numerical solution of the one-dimensional nonstationary heat equation with a volumetric thermal source. The experimentally obtained waveforms of the beam current at the collector and the accelerating voltage are used to simulate the heating source. The film thermal conductivity is numerically varied in a wide range, overlapping the entire range for real materials. The dependence of the melting threshold of a homogeneous material on the thermal conductivity is determined. The general behavior regularities of the film and substrate melting thresholds in dependence of the film thickness are established.

The results of numerical and experimental studies of zirconium irradiated by a low-energy high-current electron beam with an energy density ranging from 2.2 to 5.2 J/cm2 are presented. The dynamics of surface melting is simulated, and the thickness and lifetime of the melt, as well as the cooling rates achieved in zirconium during pulsed electron beam processing, are determined. The structure and properties of zirconium are experimentally studied, it is shown that as a result of processing, a martensitic α'-phase is formed in the layer quenched from the melt. It is established that the formation of the martensitic phase increases the surface nanohardness and wear resistance. The maximum value of the surface layer nanohardness obtained by the processing is twice higher than the initial value.

The review summarizes some achievements of materials scientists in designing high entropy alloys (HEAs) and developing production routs for their industrial implementation, as well as highlights and discusses outstanding challenges in this way. Initially, the generally accepted concept of HEAs and its criticisms have been matched. Then, suggestions for their possible application have been agglomerated. After that, typical designing algorithms for metal products and structures have been considered, focusing on the rational selection of materials. Finally, correspondence of the reported data on both characteristics and properties of HEAs, as well as procedures for their heat treatment, processing and surface engineering, has been correlated with the content of recent reference books on those for conventional metals, steels and alloys. Based on the analysis of these results, some conclusions have been drawn, including generalized knowledge gaps and challenges. Also, further research directions have been proposed.

A two-layer Fe-Cr-Al-Zr surface alloy was synthesized on a zirconium substrate by magnetron sputtering and subsequent low-energy high-current electron-beam (LEHCEB) processing. Thicknesses of the top Fe69Cr20Al11 (at.%) relatively large-grained (~1 µm) and transition Fe-Zr Cr-Al amorphous layers were about 0.7 and 0.6 µm, respectively. In turn, the amorphous layer consisted of two Fe64–54Zr8–22Cr21–17Al8–7 and Fe40–16Zr42–78Cr12–4Al6–2 (at.%) sublayers, differing in both zirconium and iron concentrations in wide ranges, which were separated by another nanocrystalline interlayer. The Fe-Cr-Al-Zr surface alloy serve as a diffusion barrier, preventing interaction of the zirconium substrate with oxygen from an environment. It was thermally stable up to ≈1173 K.

This work aims to study hexamethyldisiloxane (HMDSO) plasma polymerization in a low-pressure glow discharge in a gas flow. HMDSO was activated in a plasma-chemical reactor with a DC glow discharge in an argon flow. The argon flow (the mass flow rate was 230 mg/min) was injected in the direction of the anode from the cathode. HMDSO vapors were injected into the plasma-chemical reactor either through the hollow cathode or through the inlet located between the cathode and the anode. Polymer coatings were deposited on the substrates located in a vacuum chamber. Plasma polymerization was characterized based on the mass of coatings deposited under varying external conditions: the HMDSO mass flow rate (1-10 mg/min), the average discharge current (6-60 mA), and the discharge power (6-30 W). The operation modes of the plasma-chemical system were determined. The chemical structure of the coatings was analyzed using the infrared spectroscopy. The processes occurring in different regions of the glow discharge and at the interface near the substrate surface are proposed. A DC glow discharge in a gas flow can be used for local deposition of polymer coatings on the surface of dielectric or conductive materials.

Based on the proposed criterion of the type of heating, a classification of the sources of pulsed electron beams was carried out, both to obtain a better understanding of the nature of the thermal processes occurring under irradiation and to predict their suitability for certain applications. The melting thresholds of materials were calculated over a wide ranges of accelerating voltages and pulse durations. On the basis of calculations, a refractoriness series was proposed for metals for surface–volume pulsed heating.

Представлены результаты исследования коррозионной стойкости циркония при воздействии низкоэнергетическим сильноточным электронным пучком с плотностью энергии от 2.2 до 5.2 Дж/см2. Электрохимические результаты показывают, что после облучения НСЭП потенциал коррозии увеличивался в 2 раз, а ток и скорость коррозии уменьшались в 75 раз.

Проведены расчеты температурных полей системы Mo (пленка)/Zr (подложка) при импульсном электронно-пучковом воздействии. Представлены рассчитанные зависимости порогов плавления системы Mo (пленка)/Zr (подложка) от толщины пленки. Порог плавления пленки Mo при увеличении её толщины монотонно увеличивается и стремится к порогу плавления чистого Mo. Порог плавления подложки Zr при увеличении толщины пленки Mo монотонно увеличивается от значения порога плавления чистого циркония до бесконечности. При значениях пленки молибдена не превышающих 8 мкм первой начинает плавится подложка циркония. При дальнейшем увеличении толщины пленки, наоборот, первой начинает плавиться пленка молибдена. Расчитанны зависимости толщины расплавленного слоя подложки из циркония от плотности энергии НСЭП для систем Mo/Zr с толщинами пленок молибдена 0.10, 0.25, 0.50 и 1.00 мкм. При увеличении плотности энергии наблюдается монотонное увеличение толщины расплава. Представлены временные зависимости толщины расплава при плотностях энергии НСЭП 2.5, 3.5, 4.5 и 5.5 Дж/см2 для системы Mo/Zr с толщиной пленки 0.5 мкм.

Представлены результаты исследований по формированию многокомпонентного Fe-Cr-Al-Zr поверхностного сплава на Zr подложке с помощью низкоэнергетического сильноточного электронного пучка (НСЭП). Сплав формировался путем напыления пленки Fe-Cr-Al заданного состава на подложку с последующей НСЭП обработкой с различной плотность энергии полученной системы пленка/подложка в едином вакуумном цикле. Исследована морфология и элементный состав образцов с поверхностным сплавом. Показано, что при плотности энергии НСЭП равной 2.3 Дж/см2 происходит плавление в основном только напыленной Fe-Cr-Al пленки, при этом содержание циркония в поверхностном слое минимально и составляет 4.1 ат.%. На поверхности сплава наблюдались дефекты типа трещин и раковин. Увеличение плотности энергии приводит к более интенсивному перемешиванию материала пленки с подложкой и формированию бездефектной поверхности. При этом происходит увеличение содержания циркония в поверхностном сплаве до 54 ат. %, однако относительное содержание Fe, Cr и Al в сформированном поверхностном сплаве сохраняется и аналогично содержанию этих элементов в напыляемой пленке.