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.

A promising approach to improve the high-temperature properties of Ni-Al intermetallics is macroalloying with chromium and microalloying with a small amount of rare-earth elements (REE). For powder manufacturing processes such as the combustion synthesis technique, macro- and microalloying can be achieved by employing Cr & REE containing masteralloy powders as one of the starting reagents along with nickel and aluminum powders. This study investigated a process of dysprosium deposition onto the particles of commercial Ni-Cr powder aimed to produce the Ni-Cr-Dy masteralloy powder. The process involves pretreatment of the particle surface by low-energy high-current electron beam (LEHCEB) and uniform magnetron deposition of a thin dysprosium film. The possibility of embedding the dysprosium film into the particle's surface using an additional stage of LEHCEB treatment has been considered. It has been observed that during LEHCEB modification, a change in the particle size distribution, smoothing of the surface, and the formation of an intermetallic Dy3Ni phase in the subsurface layer occurs. A fraction of the obtained Ni-Cr-Dy powders were added to the starting powder blend for the combustion synthesis of Ni-Al-Cr-Dy porous alloys. It has been demonstrated that dysprosium uniformly distributes throughout the intermetallic scaffold of porous alloys and is localized within the Ni3Al phase in the form of enriched regions and separate inclusions.

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.

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.

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 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 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.

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.

Ni-Al intermetallic alloys have superior high-temperature properties such as excellent oxidation resistance and high yield strength, making them particularly attractive as materials for the fabrication of porous components of energy conversion and combustion devices. In this study, the cyclic oxidation resistance of highly permeable Ni-Al-Cr alloys has been investigated. The porous alloys with a structure of irregular porous scaffold comprised of welded mm-sized spheroidal strut elements forming a net of mm-sized in-terconnected pore channels (porosity of 0.55-0.60, specific surface area below 10-3 m2/g) were manu-factured by the combustion synthesis method using mu m-sized Ni, Al, and Cr powders of commercial purity as starting reagents. The surface area of alloys exposed to oxidation was calculated with an accuracy of 6% using quantitative 2D stereology. The cyclic oxidation tests were conducted in dry artificial air at 1150 degrees C for 100 h. The Ni-Al-Cr alloys, compared to Ni-Al alloys, exhibited a twofold increased oxidation resistance because of decreased scale spallation. The porous alloys were also tested in a combustion environment. The lifetime prediction showed that Ni-Al-Cr radiant burners could be used for > 10,000 h at a temperature of 1000 degrees C, which makes them relevant for application in domestic combustion appliances such as water heating boilers.(c) 2022 Elsevier B.V. All rights reserved.

TiNi alloys are very widely used materials in implant fabrication. When applied in rib replacement, they are required to be manufactured as combined porous-monolithic structures, ideally with a thin, porous part well-adhered to its monolithic substrate. Additionally, good biocompatibility, high corrosion resistance and mechanical durability are also highly demanded. So far, all these parameters have not been achieved in one material, which is why an active search in the field is still underway. In the present study, we prepared new porous-monolithic TiNi materials by sintering a TiNi powder (0–100 µm) on monolithic TiNi plates, followed by surface modification with a high-current pulsed electron beam. The obtained materials were evaluated by a set of surface and phase analysis methods, after which their corrosion resistance and biocompatibility (hemolysis, cytotoxicity, and cell viability) were evaluated. Finally, cell growth tests were conducted. In comparison with flat TiNi monoliths, the newly developed materials were found to have better corrosion resistance, also demonstrating good biocompatibility and potential for cell growth on their surface. Thus, the newly developed porous-on-monolith TiNi materials with different surface porosity and morphology showed promise as potential new-generation implants for use in rib endoprostheses.

Titanium and Ti-based alloys possess good biocompatibility and excellent corrosion resistance. This paper is devoted to an effort to create Ti-based surface alloy on specimens made of the AISI 316 L austenite steel. The Ti-based surface alloy is created by the Ti film deposition using the magnetron sputtering method followed by the low-energy high-current electron beam irradiation of the Ti film-316 L steel substrate system sur -face. Transmission electron microscopy shows that the surface alloy consists of several sublayers having different structures and phase compositions. In particular, these are alpha-Ti; TiSi2; FeTi and Fe2Ti; Fe2SiTi; Fe2Ti3O9 phases and more complex Cr13Fe35Ni3Ti7, Cr12Fe32Mo7Ni7, Cr12Fe36Mo10, Mo5Cr6Fe18 phases nearby the substrate. Phase compositions of the surface alloy layers are determined by the change in the chemical composition of the titanium-steel system and the heat depth distribution. It is shown that the formation of the Ti-based surface alloy on the AISI 316 L austenite steel surface, provides the increase in the polar component of the free surface energy from 3.2% to 34.5%. (c) 2023 Elsevier B.V. All rights reserved.

The paper is devoted to preparation Al@Dy and Al@Y core-shell structures by magnetron sputtering of Dy and Y on an Al powder. A unique powder holder system is used to obtain continuous powder movement and conglomerates destruction during the treatment. It has been established that powder particles treated using the powder holder system have a uniform coating over the entire surface. The powder coating process regularities were studied depending on the deposition time and the powder charge weight. Simple evaluation criteria for powder coating system efficiency and deposited material content based on the deposition rate were proposed. The complex modification consists of the initial core-shell structure formation and subsequent pulsed low-energy high-current electron beam treatment in the surface layer melting mode was demonstrated. The main goal of the electron beam treatment is to provide better adhesion of the “shell” material to the “core” material. Such treatment led to the deposited shell element alloying into the depth of core particles. Moreover, such electron beam treatment led to the synthesis of intermetallic compounds. In further studies, the prepared structures will be used for the uniform distribution of Dy and Y over the frame elements of self-propagating high-temperature synthesized porous materials.

AISI 316L austenite stainless steel is often used in orthopedics, although metal particles and metal ions are the major weakness of metallic prostheses associated with the tissue inflammation and proliferation. This paper presents the surface modification of the AISI 316L steel substrate to reduce its wear and corrosion rate using a combination of two methods. For that, the titanium alloy is synthesized on the substrate surface using the magnetron sputtering and electron-beam treatment. The elemental and phase compositions of the surface are investigated by energy dispersive X-ray spectrometry and X-ray diffraction. The a-C:H:SiOx coating is deposited onto substrates with the surface alloy by plasma assisted chemical vapor deposition to significantly improve the mechanical, anti-corrosion and wear-resistant properties of AISI 316L austenite stainless steel. The mechanical properties and the surface of the obtained coating are examined by nanoindentation and optical microscopy, respectively. It is shown that substrates with the surface alloy and a-C:H:SiOx coating manifest stability to autoclave sterilization proven by the results of optical microscopy.

The paper presents a new method for coating commercial metal powders with rare-earth elements (REE). This method consists of a two-step treatment of a metal powder in a single vacuum cycle, namely the pulsed irradiation above the melting point by a low-energy high-current electron beam with subsequent magnetron sputtering of REE. This research reports the preparation of Al-Dy core-shell powder with an average diameter of particles of 40 mu m. A powder holder system, providing rotary agitation and shaking of powder, was used to guarantee the uniform processing of each particle. It was established that electron beam irradiation leads to smoothing and cleaning the Al particles from surface oxides. With an increase in the number of pulses, the uniformity of processing increases; however, an increase in the average particle size occurs. Subsequent magnetron sputtering allows completely coating the surface of processed powder with dysprosium. The proposed method can be suitable for fabricating different metal-REE core-shell powders with necessary changes in processing parameters.

To date, many results of studies of surface alloys have been published, but no approaches have been developed to predict their quantitative composition that can assist to design new types of coatings. This paper proposes a methodology for prediction the atomic and mass contents of elements in the surface alloys formed by pulsed liquid-state mixing of pre-deposited films and an upper layer of a substrate. The methodology validity has been verified experimentally on the example of a Cr–Zr surface alloy that is of particular interest due to its possible use in the nuclear industry. The surface alloy has been synthesized by irradiation of a Cr/Zr film-substrate system with a low-energy high-current electron-beam (LEHCEB) of microsecond duration. The results have showed good agreement between the predicted and experimental data with an accuracy satisfactory for practical applications. Some observed discrepancies are explained by the pulse-to-pulse dispersion of the energy densities during LEHCEB irradiation.

ФИЗИКО-МЕХАНИЧЕСКИЕ СВОЙСТВА ТРЁХКОМПОНЕНТНЫХ ПОВЕРХНОСТНЫХ СПЛАВОВ НА ОСНОВЕ ТИТАНА, СИНТЕЗИРОВАННЫХНА TiNi-ПОДЛОЖКЕ ЭЛЕКТРОННО-ПУЧКОВЫМ СПОСОБОМ 1 Дьяченко Ф

The results of crack formation in a Cr–Zr surface alloy formed by a low-energy high-current electron beam are presented. The morphology and elemental composition of the surface alloy in the area of crack formation are investigated. It is shown that cracks propagate along the surface regardless of the location of pits and grooves, which indicates a greater dependence of cracking on the internal stresses rather than the roughness or other structural factors. It is found out that the distribution of elements affects the cracking of the surface alloy, which is indicated by its nearly equiatomic elemental composition in the area of crack formation.