Представлены результаты исследований импульсного периодического тлеющего разряда в потоке аргона при атмосферном давлении, при частоте следования импульсов до 100 кГц, длительности импульса несколько микросекунд и при значениях тока в импульсе от нескольких десятков миллиампер до 1 А. Выявлены условия, при которых в разрядной плазме наблюдается присутствие ионов и атомов материалов катодной вставки, в качестве которых применялись легкоплавкие металлы. Показано, что при остывании атомов металлов происходит их слипание в наноразмерные частицы и формирование порошков оксидов металлов.

The authors investigated the microstructure and mechanical characteristics of 56GM steel-based composite produced by wire electron-beam additive manufacturing with the addition of W + WC(Ni) powders during printing. The analysis demonstrates that 56GM/(W + WC(Ni)) composite alloy is characterised by a gradient structure consisting of 56GM base layer, 56GM – 56GM/(W + WC(Ni)) intermediate layer and 56GM/(W + WC(Ni)) composite layer. The base layer of 56GM steel is characterized by a multidirectional acicular structure, which corresponds to the ferrite-martensite state. In 56GM – 56GM/(W + WC(Ni)) intermediate layer the acicular structure becomes less pronounced. In 56GM/(W + WC(Ni)) composite layer an equiaxed grain structure is formed, with an average grain size of 8.59 μm, along the boundaries of which cracks are observed. WC particles are located mainly along the boundaries of small grains and in small quantities inside the grains themselves. It was found that 56GM/(W + WC(Ni)) composite is mainly composed of α-Fe (~80.6 vol. %), Ni (~6 vol. %), WC carbide phase (~10.3 vol. %) and γ-Fe (3 vol. %). The structure and properties of initial 56GM steel change both in the area of direct addition of alloying powder and in the underlying layers due to diffusion processes and infiltration of W + WC(Ni). Microhardness values increase from ~3.5 GPa to ~6.5 GPa with distance from the substrate to the composite layer. In uniaxial tensile tests, the ultimate tensile strength and yield strength values reached 1100 – 1200 MPa and 835 MPa in the intermediate layer, respectively.

The paper presents the results of a study of the current-voltage characteristics and optical emission spectra of plasma of a atmospheric pressure pulsed discharge plasma at a frequency of several tens of kilohertz and a pulse duration of up to 10 μs, in the mode of generation of plasma flows containing metal particles. The features of the plasma generator conclude in combination of the design of electrodes, as well as the modes of electric and gas supply of the discharge system. The cathode is a crucible containing a melting insert which allows the discharge operation in a low-current form with a current of 40 mA to 1 A, at a sufficiently high voltage of 150 to 200 V, without transition to arc discharge mode. Such parameters make it possible to generate atomic flows of a melting cathode insert, which are blown out by a jet of working argon gas, pumped at a flow rate of 1 l/min, outside the discharge system. The entry of a metal component into a gas-discharge plasma affects the parameters of the discharge operation, as well as the properties of its optical emission. In the context of this phenomenon, the spectral distributions of the intensity of optical radiation corresponding to the lines of magnesium, indium, and zinc were investigated, as well as their time dependence during the current pulse period operation, in relation to the identification of physical features leading to stable generation of flows of metal atoms at atmospheric pressure.

We have synthesized magneto-dielectric coatings with thicknesses 290, 550, 5460 and 6063 nm with an upper protective and electrically insulating layer of alumina ceramic and a lower magnetic iron-nickel layer. The coatings were formed in a helium atmosphere at forevacuum pressures (from 1.5 to 15 Pa) by electron-beam evaporation of a mixture of iron and nickel fragments, and of a solid alumina ceramic target placed in a separate crucible. Magnetic properties of the coatings have been studied by a ferromagnetic resonance technique with estimation of the effective saturation magnetization together with evaluation of the signal-to-noise ratio and relative broadening of the resonance lines. Owing to the layer of alumina ceramic, the values of relative dielectric permittivity (5.6) and electrical conductivity (0.78-3.00 mS/m) remain typical for thin-film dielectrics.

The structural and phase state of the surface layers of technically pure titanium (VT1-0 alloy) implanted with aluminum ions in three states (submicrocrystalline, ultrafine-grained, and fine-grained) obtained by multiple uniaxial pressing (abc pressing) followed by multipass rolling in groove rolls at room temperature and subsequent annealing at 573, 673, and 773 K for 1 h, respectively, has been studied by transmission electron microscopy and energy dispersive X-ray spectroscopy on foils cut perpendicular to the machined sample surface. Ion implantation has been performed for 8 h and 20 min at an irradiation dose of 10 × 1017 ions/cm2 and a temperature of 623 K. It has been found that the implantation led to the formation of a gradient structure consisting of five layers. For each layer, the thickness, phase composition, and shape and arrangement of second-phase particles have been determined and the α-Ti grain size and the size, distribution density, and volume fractions of separated particles have been measured. It has been established that the implantation causes the formation of Ti3Al and TiAl3 intermetallic phases. Ti3Al particles have a lamellar shape and are located inside parts of α-Ti grains, while TiAl3 particles have a rounded shape and are arranged randomly.

Bacterial biofilms on titanium implant surfaces may lead to the development ofperi-implant diseases. For the first time, Ti6Al4V/Cu prepared by double-wire electron beam additive manufacturing (EBAM) were subjected to in -vitro antimicrobial test. The antimicrobial activity of the materials was investigated against S.aureus and C. albicans strains depending upon the amount of copper added. Increasing the copper content in material to 9.7 wt % allowed achieving 99% bacterial population reduction on the copper-containing substrate. Such an enhanced antimicrobial acivity of the substrate was caused by the release of copper ions from the Ti6Al4/Cu alloys.

Using the method of high-frequency ion-plasma sputtering (magnetron highfrequency deposition under conditions of ion-plasma assisted using a gas (argon) plasma generator "PINK") on the surface of a high-entropy CoFeCrMnNi alloy of non-equiatomic composition. Boron-containing coatings of the elemental composition Al - Mg - B and Mg - Ti - B with a thickness of 3 mu m are formed. Using transmission electron diffraction microscopy, it was found that the coatings are amorphous-crystalline, i.e. contain nanosized 1.5-2 nm islands of the crystalline phase located in an amorphous matrix. It is shown that the coating deposition is accompanied by the formation in the substrate layer (high-entropy alloy) adjacent to the coating of a nanocrystalline structure with a crystallite size of 25-40 nm. At the boundaries of the crystallites, particles of iron boride of the FeB and Fe3B compositions are revealed, which indicate the penetration of boron into the substrate. The particle size of iron boride is 5-8 nm.

Earlier studies have shown that it is possible to successfully obtain Ti6Al4V-Cu alloys with various copper concentrations using the double-wire electron beam additive manufacturing. Obtaining these alloys is of a practical interest for creating a titanium-base composite material with reduced risk of spontaneous combustion, which could be used in friction units at elevated temperatures. This article presents a study of the tribological properties of Ti6Al4V titanium alloy samples produced by layer-by-layer electron beam melting with the addition of Cu from a wire. The results of this work demonstrate an improved wear resistance of Ti6Al4V-Cu alloys. Such a result was achieved due to the grain refinement and precipitation of intermetallic Ti2Cu nanosized particles. For instance, the value of linear wear of alloys Ti6Al4V-6 wt.% Cu and Ti6Al4V-9.7 wt.% Cu is 46 % and 40 % less, respectively, as compared to the original alloy Ti6Al4V. It has been established that the plastic deformation penetration below the worn surface decreases with the increase in the concentration of copper in titanium alloy samples.

The fine structure of a submicrocrystalline (SMC) VT1-0 alloy is studied after its implantation with aluminum ions at the irradiation doses of 1·10 17 , 5·10 17 , and 10·10 17 ion/cm 2 . A gradient structure is observed to form in the alloy in this state, which consists of five different layers: 1 – oxide layer, 2 – ion-doped layer, 3 – layer with refined grain structure, 4 – layer of residual implantation influence, 5 – layer with initial grain structure. It is shown that at all of the implantation doses used in the study there is no dislocation structure in layers 2 and 3, and the dislocations in layers 4 and 5 form a network substructure. The internal stresses in layers 2 and 3 represent an elastic component of long-range stresses, in layer 4 – long-range and shear stresses, and in layer 5 – shear stresses only.

Методом просвечивающей электронной дифракционной микроскопии и энергодисперсионной рентгеновской спектроскопии на фольгах, вырезанных перпендикулярно обработанной поверхности образца, проведено исследование структурно-фазового состояния поверхностных слоев имплантированного ионами алюминия технически чистого титана (сплав марки ВТ1-0) в трех состояниях: субмикрокристаллическом, ультрамелкозернистом и мелкозернистом, полученных после комбинированного метода многократного одноосного прессования (аbc-прессование) с последующей многоходовой прокаткой в ручьевых валках при комнатной температуре и последующего отжига соответственно при 573, 673 и 773 К, 1 час. Ионная имплантация проводилась в течение 8 часов 20 минут, дозе облучения 10×1017 ион/см2 и температуре 623 К. Установлено, что имплантация привела к формированию градиентной структуры состоящей из 5 слоев. Для каждого слоя определена его толщина, фазовый состав, форма и расположение частиц вторых фаз, измерены размеры зерен a-Ti, размеры, плотность распределения и объемные доли выделившихся частиц. Установлено, что имплантация привела к образованию интерметаллидных фаз Ti3Al и TiAl3. Частицы Ti3Al обладают пластинчатой формой и располагаются внутри части зерен a-Ti, частицы TiAl3 имеют округлую форму и располагаются случайным образом.

We have explored the generation of plasma with high content (up to 70%) of calcium ions. The plasma is formed using an electron beam bombarding solid targets with electron energy up to 20 keV and power density up to 600 W/cm 2 . Target materials used are simple and readily available school chalk, limescale, and gypsum building plaster. Electron-beam erosion of the target material, production of unbound calcium atoms, and their ionization occur in a single cycle at a background pressure of a few pascals. This approach minimizes the effect of target surface charging by beam electrons and provides effective ionization of calcium-containing materials. The method described here is an alternative to the conventional method for the generation of calcium ions based on electron-cyclotron resonance systems, and is technically easier to implement.

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∙10 17 , 5∙10 17 and 10∙10 17 ion/cm 2 . 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 Al 3 Ti and AlTi 3 phases, β-phase titanium and aluminum oxide (Al 2 O 3 ). The increased irradiation exposure results in the formation of a thicker implanted layer without changing its phase composition.

We report the study of commercially pure titanium (VT1-0 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 x 1017, 5 x 1017, and 10 x 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 i Ti2O3). Increasing the irradiation dose does not qualitatively change the alloy phase composition, but affects the quantitative characteristics of the formed secondary phases.

Using the transmission electron microscopy technique, we have studied the structural-phase state of UFG titanium with an average grain size similar to 0.2 mu m 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 1.10(18) ion/cm(2). 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 alpha-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 alpha-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, beta-Ti, TiAl3, Ti3Al, TiC, and TiO2.

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 M 23 (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.

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 change in phase composition and fine texture occurring in the  ferritic-pearlitic 0.18C – 1Cr – 3Ni – 1Mo – Fe, 0.3C – 1Cr – 1Mn – 1Si – Fe  and 0.34C – 1Cr – 1Ni – 1Mo – Fe steels under electrolytic plasma carbonitriding  was  investigated  by  transmission  electron  microscopy  (TEM) method conducted on thin foils. Carbonitriding was implemented by surface saturation with nitrogen and carbon in aqueous  solution under the temperature of 800  –  860  °C during 5  minutes. All  steels were investigated before and after carbonitriding. It was ascertained that in the original state steel is given as a mixture of grains  of pearlite and ferrite. Carbonitriding has led to creation of modified  layers: the bigger was the amount of pearlite before the beginning of  carbonitriding, the thicker was modified layer. Carbonitriding resulted  in significant qualitative changes in phase state and structure of steel.  It was revealed that in the surface area of modified layer along the  matrix, there were also particles of other phases: carbides, nitrides and  carbonitrides. In the course of removing from the surface of carbonitrided sample, their complete set and volume fractions decrease and at  the end of modified layer only one carbide phase is present in all steels,  i.e. cementite. It was found that matrix of all steels after carbonitriding is tempered packet (lath) and lamellar martensite. In the surface  area of carbonitrided layer the volume fractions of lath and lamellar  martensite depend on the original state of steel – the bigger was the  amount of pearlite in steel the less lath martensite and the more lamellar martensite was formed. Such a dependency cannot be observed in  the central area, and at the end of carbonitrided layer volume fractions  of martensite packets and plates are commensurate.

We report our results on nitriding of industrially-pure titanium VT1-0 in the plasma formed by continuous electron beam created by a fore-vacuum plasma-cathode electron source, at different temperatures of the titanium sample surface (700-1020 degrees C) and electron beam energy (4-6 keV), in medium vacuum (5 Pa) of nitrogen. Electron beam was used for direct treatment and heating of the sample as well as for the plasma generation. It is demonstrated that such parameters of the Ti sample as nitrogen content, the depth of nitride layer, Vickers microhardness, and wear-resistance grow with sample temperature and beam energy. Such positive effects happen, likely, due to enhanced generation of active atoms and atomic ions of nitrogen in beam-produced plasmas in medium vacuum.