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

The features of the method for generating gas-vapor plasma and the characteristics of a high-power ion beam (HPIB) obtained in a vacuum diode with a graphite cathode using a plasma-forming high-voltage nanosecond pulse are described. The cathode material and the two-pulse mode of operation of the TEMP-4 type diode make it possible to form a multicomponent nanosecond HPIB with a maximum ion energy of up to 1 MeV, a particle flux density on the surface of ~ 1013 ion/cm2, and a power density on the sample surface of up to 107 W/cm2 to modify the surface properties of structural materials. Materials are published within the framework of scientific discussion. The authors invite researchers of the generation of high-power beams of non-gas ions and the processes of beam modification of solid-state materials to discuss the topics of this article.

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.

The tungsten surface was processed by high power pulsed ion beam at the TEMP accelerator (Cn+ ions, accelerating voltage 200 ± 10 kV, energy density of a single pulse 2.6 – 3.0 J/cm2). Changes in the relief and structure of the surface of tungsten samples were studied by scanning electron microscopy. After treatment with a powerful pulsed ion beam (MIIP), defects in the form of craters form on the surface of tungsten. The number of craters decreases with an increase in the number of impact pulses. After exposure to 3 pulses, microcraters are forms in the surface layer along the grain boundaries. After 10 pulses, there are practically no cracks on the irradiated surface. An increase in the number of pulses leads to the formation of a more equiaxed ultrafine-grained structure in the near-surface layer of tungsten.

Поверхность тантала облучали мощным импульсным ионным пучком на ускорителе ТЕМП Томского политехнического университета (Cn+, ускоряющее напряжение 200±10 kV, плотность энергии в импульсе 2.6–3 Дж/cм2). Изменение топографии поверхности тантала после воздействия мощного импульсного ионного пучка исследовали с помощью растровой электронной микроскопии. Изменения рельефа и структуры поверхности образцов Та изучали методом сканирующей электронной микроскопии.

This article presents a review of experimental investigations of changes in the structure and properties of the surface and near-surface layers of various materials (steels, metal alloys, ceramics, and graphite) in the area of a barcode applied by continuous laser radiation and short (nanosecond) and ultrashort (femto- and picosecond) laser pulses.

An analysis of the advantages of laser marking is carried out in comparison with other methods of forming a given surface relief of structural materials, forming barcodes, and reading them. The necessary conditions for stable reading of barcodes, described by the value of the contrast ratio, are formulated. The elements of the prints of the laser exposure pattern that make up the barcode are classified, and an example of measuring and calculating the contrast ratio of samples using spectrophotometry is given. The parameters of the surface relief in the areas of the applied barcode are measured using scanning probe microscopy. The analysis of the influence of the parameters of laser radiation on the geometric characteristics of the elements of the barcode and the value of its contrast ratio is carried out.

This work represents the characterization of materials surface before and after laser processing with macrophotography, optical metallography, and scanning electron microscopy before and after thermal exposure. The factors influencing the reliability of the laser-induced code readability have been determined as color and contrast. The range of stability of the code readability under thermal influence on the structural materials under study was determined, which allows improving the reliability of the laser-induced marking codes readability. The research objects in this paper were samples of the following materials: alloys based on copper, aluminum, and iron with laser-induced codes of various types applied on the surface. This work aimed to research the stability of laser-induced codes readability after thermal exposure using macrophotography, optical metallography and scanning electron microscopy on structural materials of various purposes before and after laser processing (when forming a binary matrix code). The research results obtained and presented in this article on the stability of laser-induced codes reading under thermal action on structural materials can be used in different fields of industry, when marking products of heavy, general, medium, and precision engineering, as well as for marking metal products and blank parts. The results of this research are also planned to be used for further analysis of the occurring damage, leading to reading errors due to mechanical and chemical influences. It is planned to evaluate the limit values of the parameters that determine the degree of degradation at which the encoding will be considered to have lost the recognizing ability. Requirements for the quality and permissible code damage will also be developed to ensure their reliable identification.

Effect of the pulsed soft X-ray fluxes (PSXF) on the surface topography of metals (Mg and Cu) has been investigated. Soft pulse X-ray irradiation (energy quanta of 0.1-1.0 keV) were carried out on a high-current MIG generator. The sample of magnesium was located at a distance of 10 cm from the X-ray source. Since the distance to the sample significantly exceeded the size of the X-ray beam, it can be assumed that the density of the X-ray radiation flow to the magnesium sample was uniform. The duration of the radiation pulse was 100 ns, and the radiation energy density in the pulse varied from 13 to 19 J/cm 2 . As a result of melting under the action of PSXF of the near-surface layer of metals and subsequent solidification, a wavy relief is formed on their surface. Defects in the form of craters, which usually occur after the impact of a powerful pulsed ion flow on metals, were not detected.

The phase and elemental composition of the near-surface layer of nitrided ferrovanadium irradiated with a high-power ion beam has been investigated by XRD and SEM methods. The impact of a powerful beam of the Temp-4M setup with an energy of carbon ions of 250 keV at a radiation pulse duration 10–7 s and a power density of charged particles qi ≥ 106 W/cm2 causes melting of the Fe–VN composite and partial evaporation of elements with a high vapor pressure from the surface layer. High-speed solidification of the melt on the surface of the Fe–VN target leads to the formation of highly dispersed vanadium nitride and tetragonal carbide Fe23C6 in the modified layer. After irradiation of Fe–VN with a high-power beam with qi ≈ 107 W/cm2 at a dose of ~ 1015 cm–2, a violation of the translational invariance of the distribution of intercalated carbon atoms, a structural redistribution of Fe and V atoms, and the formation of X-ray amorphous microliquations of Fe–V and gas–carbon complexes are observed in the modified layer.

In this study, the surfaces of AISI 321 stainless steel samples were irradiated with one shot of a high-power ion beam (HPIB) at pulse energy densities of 1 and 3 J/cm 2 . The surface morphology and structural-phase state in the near-surface layers of the treated samples were analyzed using scanning electron microscopy and electron backscatter diffraction. Additionally, the influence of HPIB processing on the resistance to intergranular corrosion was investigated using electrochemical experiments.

The corrosion resistance of Mg–Al–Zn magnesium alloy with coarse-grained and ultrafine-grained structures before and after the treatment of the surface of the alloy with pulsed nanosecond laser irradiation is studied. It is found that this treatment significantly increases the resistance of the alloy to its dissolution in a 0.9% NaCl saline only under the condition of preliminary formation of a uniform ultrafine-grained structure in the bulk of the sample. The observed effect can be considered as a promising method for the treatment of the surface of medical devices made of biodegradable magnesium alloys.

An analysis of the influence of thermomechanical treatment (TMT) (rolling to a strain degree of 50%, annealing at a temperatures of 600–1200°C, 1 h) on the microstructure and phase composition of a VZh171 alloy in the initial state and after its bulk nitriding is performed. It is shown that nitriding leads to an increase in the thermal stability of the alloy microstructure. While a primary recrystallization and formation of finegrained structure occurs in an non-nitrided alloy quite intensively at the temperature above 1000°C, the process of collective recrystallization does not gain any significant development in the nitrided alloy even at an annealing temperature of 1200°C, and the microstructure remains ultrafine-grained (grain size 5–10 μm). The mechanical properties of the nitrided and non-nitrided alloy are investigated. It is established that nitriding has no significant effect on the alloy strength at room temperature. In the tests at 800°C, the maximum strength and the minimum plasticity are demonstrated by the nitrided alloy after rolling and subsequent annealing at 600°C. The optimum ratio of the ultimate tensile strength (480 MPa) to plasticity (elongation to fracture 23%) is observed in the nitrided alloy after TMT and annealing at 800°C.

The study covers the topography and structural phase state of VT1-0 and VT6 submicrocrystalline titanium alloy subsurface layers irradiated by high power pulsed carbon ion beams (ion energy is 250 keV, pulse duration is ~100 ns, pulse current density is 150–200 A/cm2; surface energy density of a single pulse is j ~ 3 J/cm2 when irradiating VT1-0 titanium alloy samples and j ~ 1 J/cm2 when processing VT6 titanium alloy samples; pulse number is 1, 5, 10, and 50). The surface of samples was subjected to preliminary mechanical grinding and polishing before irradiation. It was shown that surface defects are formed on the surface of the alloys after irradiation, namely craters of different shapes and geometries with a diameter from fractions of a micron to 80–100 μm. At the same time, the grain structure in the subsurface layer becomes more homogeneous in terms of grain size and equiaxial properties. The initial state of titanium alloys is characterized by a fairly homogeneous structure with an average grain size of ~0,31 μm for VT1-0 and ~0,9 μm for VT6. After one irradiation pulse, grain growth to 0,54 μm in the transverse direction is observed in the subsurface layer of the VT1-0 alloy (j ~ 3 J/cm2), while grain size decreases to ~ 0,54 μm in the VT6 alloy (j ~ 1 J/cm2). After 50 pulses, the average grain size in the subsurface layer reaches ~2,2 μm for the VT1-0 alloy and ~1,6 μm for VT6. It should be noted that a rather uniform structure with equiaxed grains is formed as early as after treating with 1 high power ion beam pulse.

The effect of the pulsed soft X-ray flux on the topography of surface the VТ 1-0 titanium alloy has been studied. The radiation energy density on the surface of the sample is ~10 J/cm 2 for one pulse. It is found that a corrugated topography is formed on the surface of titanium as a result of melting followed by freezing: a cellular- or mesh-type topography is formed after one X-ray pulse, the mesh-type topography becomes more sharply defined after two pulses, and the surface of titanium is melted and the mesh structure is almost invisible after three pulses. Crater-like defects are not found, but small cracks are formed on the surface of titanium after melting caused by pulsed X-ray exposure followed by fast cooling of the molten metal.

The effect of the femtosecond laser irradiation on the formation of oxide layers on the surface of a commercially pure titanium VT1-0 was studied. The methods of X-ray analysis, scanning electron and transmission electron microscopies were used to study the structural and phase state of oxide layers. As a result of the femtosecond laser irradiation, the porous multi-phase nanocrystalline oxide coating with a thickness of 50 mu m is formed on the titanium surface. The coating consists of titanium oxides: TiO2 (rutile and anatase), TiO and Ti3O5.

The topography of surface layers of 12Cr18Ni10Ti (AISI 321) steel after pulsed high-power Cn+ ion beams irradiation was investigated by scanning electron microscopy. A thin foil was prepared from the cross section of a crater with the use of a focused ion beam in the column of a two-beam electron-ion microscope. The microstructure and chemical composition of the crater were studied by transmission electron microscopy. It is shown that the near-surface layer (~2 μm in depth) of the crater is represented by an area of columnar grains elongated in the direction of the surface. Under the layer of columnar grains, the region with equiaxial submicrocrystalline grains is situated.

This paper describes the optimal modes of initiation of self-propagating hightemperature synthesis with the help of an electron beam on the example of a Ti–Al–C powder mixture. A pulsed electron beam with a particle energy of tens of kiloelectronvolts and a duration of hundreds of microseconds is used. Morphology, structure, and elemental composition of formed products in the form of Ti 3 AlC 2 and TiC are studied.