Electron-beam Method Research Articles

Microstructure and strength of a 3D-printed Ti–6Al–4V alloy subjected to high-pressure torsion

Currently, one of the effective 3D printing methods is wire-feed electron-beam additive manufacturing (EBAM), which allows producing large-sized commercial billets from Ti–6Al–4V titanium alloy. However, Ti–6Al–4V alloy produced by this method demonstrates reduced strength properties. It is known that it is possible to increase the strength properties of metallic materials by refining their grain structure by high-pressure torsion (HPT). This work is aimed at studying the influence of high-pressure torsion on the microstructure, and mechanical strength of a structural Ti–6Al–4V titanium alloy produced by the wire-feed electron-beam additive manufacturing method. The microstructure of a 3D-printed Ti–6Al–4V alloy in the initial state, and after high-pressure torsion, was studied using optical, scanning and transmission electron microscopy. An EBSD analysis of the material in its original state was carried out. The microhardness of the material in the initial and deformed states was measured. Using the dependence of the yield strength on microhardness, the estimated mechanical strength of the material after processing by the high-pressure torsion method was determined. The microstructural features of the 3D-printed Ti–6Al–4V alloy after high-pressure torsion, which provide increased strength of this material, are discussed. The research results demonstrate that 3D printing, using the electron-beam additive manufacturing method, allows producing a Ti–6Al–4V titanium alloy with a microstructure unusual for this material, which consists of columnar primary β-grains with a transverse size of 1–2mm, inside of which martensitic α'-Ti needles are located. Thin β-Ti layers with a thickness of about 200nm are observed between the α'-Ti needles. Further deformation treatment of the alloy, using the high-pressure torsion method, allowed forming an ultrafine-grained structure in its volume, presumably consisting of α-grains with an average size of (25±10)nm. High-pressure torsion of the 3D-printed alloy allowed achieving rather high microhardness values of (448±5)НV0.1, which, according to the HV=2.8–3σy ratio, corresponds to the estimated yield strength of approximately 1460MPa.

Determination of Cast-Metal Structures and Welded Joints After Electron-Beam Welding of the Intermetallic Titanium Alloys Ti−28Al−7Nb−2Mo−2Cr Obtained by Electron-Beam Melting Method

Determination of Cast-Metal Structures and Welded Joints After Electron-Beam Welding of the Intermetallic Titanium Alloys Ti−28Al−7Nb−2Mo−2Cr Obtained by Electron-Beam Melting Method

Determining technological parameters for obtaining ta15 titanium alloy blanks with improved mechanical characteristics using the electron-beam 3D printing method

The object of this study is the process of electron beam 3D printing of articles made of TA15 titanium alloy powder. Peculiarities of the structure and properties formation of alloy blanks, obtained by this method have been described. Influence of process parameters (electron beam power and geometric scanning parameters) on the characteristics of the material were considered. Step of displacement of the beam trajectory changed from 0.1 to 0.25 mm with an interval of 0.05 mm. Specific energy of the electron beam varied from 20 to 70 J/mm3 for every trajectory displacement step. The macrostructure was examined visually while the microstructure was studied by optical microscopy. Mechanical properties were determined by uniaxial tension and impact bending tests. It was established that depending on the 3D printing parameters the macrostructure of most samples is dense but with unfavorable parameters non-fusions or shrinkage porosity defects may form. The microstructure of the dendritic type has an α´+β lamellar-acicular morphology, its dispersity and shape of α´–phase areas vary depending on the process parameters. A scanning step of 0.2 mm and a beam energy of 40 J/mm3 allows obtaining a dispersed microstructure in which there are no non-fusions and shrinkage micropores. The value of the Rm is 27 %, and the R0.2 is 24 % higher than that of the alloy obtained by the conventional technology of electron beam melting. The A5 is 3.2 times higher. However, impact toughness of the sample with dendrite unfavorable orientation to the direction of load applying may be lower compared to conventional technology. The results could be used for devising commercial technology of high strength titanium alloys parts produced by 3D printing

Электронно-лучевой метод стерилизации почтовой корреспонденции

This work is a logical continuation of the previously published article «Disinfection of postal correspondence as a tool to counteract postal bioterrorism» and is devoted to the study of the electron beam method (ELM) sterilization of postal correspondence (PC). The possibility of using pathogenic biological agents (PBAs) for terrorist purposes using PCs poses the maximum danger among possible threats, since the consequences, if terrorists achieve their goals, will be catastrophic. The rapid development of biological sciences leads to an ever-expanding list of PBAs due to the discovery of pathogens of new infections, the creation of genetically modified and hybrid microorganisms. A special place is occupied by the problem of ensuring the biological safety (BB) of PC recipients, associated with the possibility of committing terrorist acts, including through infected mail. In this regard, it is relevant to search for methods of providing PC security that would reduce the risks of infection of technical personnel of communication offices to a minimum or eliminate them altogether. In order to prevent damage to the PBA of the technical personnel of the PC processing points and the final recipients by mail, their disinfection is justified. Keywords: postal bioterrorism, biological security, pathogenic biological agent, mail, mail processing point, electron beam method.

Photocatalytic degradation of methylene blue by TiO2/Nd2O3 composite thin films

To improve the photocatalytic property of TiO2 thin films, the composite thin films of TiO2/Nd2O3 structure were fabricated by electron-beam physical vapor deposition method, and the photocatalytic property of the fabricated films was experimentally studied in the present work. The XRD and Raman analyses show that the TiO2/Nd2O3 films are mainly hexagonal crystalline phase of Nd2O3. The XPS analysis for the chemical state changes of Ti, O and Nd of the basic elements in the films is confirming the electron flow in the internal electric field which generated in the TiO2/Nd2O3 films. The surface morphology shows the lattice distortion which affects the changes in the energy band structure. Moreover, the formation of n-n homojunctions improved the separation efficiency of electrons and holes, and enhanced the catalytic activity. The photocatalytic performance for the methylene blue target dye shows that the sample with TiO2 thickness of 20–25 nm has better performance, high degradation efficiency and high reaction rate.

SUBSTANTIATION OF EXPEDIENCY OF USE OF TOOL HIGH-SPEED CUTTING STEELS AS COATINGS IN FRICTION UNITS

The analysis of modern researches in the field of composite materials on the basis of tungsten carbide used as surfacing materials is carried out. In particular, the influence of morphology of carbide phase on wear resistance of materials is analyzed. Particular attention is paid to the analysis of conducted studies of ultrafine and nanograined composite materials, their comparative analysis with conventional micrograin coatings. The expediency of research of application of tool high-speed steels as coatings, applied by vacuum electron-beam processing method, which allows to organize micro-metallurgical process with minimal impact on the base metal and possibility to form hardened layer, the thickness of which is adjustable within wide limits, is substantiated.

Improved performance of H-diamond MOSFETs with ZrO2/Al2O3 gate dielectric stacks deposited by electron beam method

H-diamond MOSFETs with ZrO2/Al2O3 gate dielectric stacks were fabricated using an electron beam (EB) evaporation technique. The fixed positive charge in the ZrO2 contact layer depleted the two-dimensional hole gas to achieve normally off operation. Thanks to the leakage suppression of Al2O3 blocking layer, the device exhibited a considerably low gate leakage current of 1.8 × 10−6 A/cm2 at VGS = −5 V. Contributed from the relatively lower estimated interfacial state density (1.45 × 1012 cm−2 eV−1) and uncontaminated ZrO2/Al2O3 gate interface, the maximum mobility was estimated to be 345.8 cm2/V·s at VGS of −2 V, indicating excellent interfacial property of ZrO2/H-diamond. The hole mobility remains an almost constant of about 150 cm2/V·s for −4 V ≤ VGS ≤ −7 V. The maximum drain current density with 6 μm-gate length was −112 mA/mm at VGS of −7 V. These results will provide an approach for fabricating high-performance H-diamond FETs.

Sustainable Surface Engineering Techniques: Evaluating the Environmental Footprint of Laser and Electron Beam Methods

This study provides an extensive overview of the latest developments in metal surface engineering, including methodologies, characterizations, and applications. The study highlights how important surface engineering is for improving metallic materials’ functionality and performance across a range of sectors. Therefore, a series of techniques are presented in this paper for evaluating design surfaces’ mechanical properties, topological properties, and microstructure. This paper presents a review of current advances in the field, focusing on functionalized surfaces for energy applications, nanostructured coatings for corrosion protection, and biomedical applications of modified surfaces. Since lasers and electron beams are mechanically and tribologically superior, there is a long discussion about their environmental footprint. A special focus in the study is on surface functionalization, nanostructured coatings, corrosion protection, and biological applications, as well as recent developments in the field. The paper also discusses the impact they have on the environment. Surface engineering approaches have long been known to enhance corrosion protection, wear resistance, and component functionality in aerospace, automotive, electronics, and healthcare sectors. Thus, the paper’s conclusion emphasizes that more research and development are needed to overcome constraints and take advantage of emerging trends in surface engineering in order to overcome constraints and take advantage of new trends. The paper provides a solid foundation for future research and development in a range of industries affected by surface engineering.

THERMOLUMINESCENT AND DOSIMETRIC PROPERTIES OF ZIRCONIUM DIOXIDE CERAMICS IRRADIATED WITH HIGH DOSES OF PULSE ELECTRON BEAM

The paper presents the results of a study of thermoluminescent (TL) and dosimetric properties of monoclinic zirconium dioxide ceramics of two types: synthesized by sintering in an electric furnace at T = 700–1700 °C and in a flow of high-energy electrons (1.4 MeV) with a high power density. It has been established that annealing of ceramics of the first type at T>1000 °C leads to a significant increase in the crystallite size, which correlates with a significant increase in the intensity of the TL peak at 390 K after irradiation of the samples with high doses (on the order of kGy) of a pulsed electron beam (130 keV). Type 2 ceramics synthesized by the electron beam method have the maximum TL response. The work also discusses the patterns of influence of synthesis conditions on the kinetic parameters of TL and the nonlinearity coefficients of dose dependencies. The presence of an intense isolated TL peak, the sublinear nature of most dose dependencies, and negligible fading indicate the promise of the ceramics synthesized in this work for measuring high doses (several to tens of kGy).

Physical-Mechanical Properties of the Ti–Ni–Nb–Si-Based Surface Alloy Synthesized on the TiNi Substrate by the Electron-Beam Method

Physical-Mechanical Properties of the Ti–Ni–Nb–Si-Based Surface Alloy Synthesized on the TiNi Substrate by the Electron-Beam Method

Performance evaluation of a single microchannel plate with large length-to-diameter ratio

The conventional microchannel plate (MCP) detector has found widespread application in various fields. This article focuses on investigating the performance of a single MCP with a large length-to-diameter ratio (L/D) of 80:1, particularly for single electron counting. To enhance MCP performance, alumina with a high secondary electron yield (SEY) is coated onto the MCP using atomic layer deposition (ALD). The SEYs of alumina thin films with different thicknesses are measured using a pulsing electron beam method. The 80:1 L/D MCPs operate in electron counting mode, and the optimal alumina thickness is determined through a comparative study of MCP performance before and after coating. The relationships between maximum SEY, primary electron energy, gain, peak-to-valley ratio (P/V), and pulse height resolution (PHR) are analyzed. After alumina coating, the single 80:1 MCP exhibits improved gain, P/V and PHR. The optimal P/V and PHR of a single MCP as functions of the primary electron energy align with the relationship between the SEY of the alumina coating and the primary electron energy. Additionally, the variation of DC gain with extracted charge is investigated. This article provides valuable insights for parameter selection in achieving the optimal working state of MCP and explores the potential application of single electron counting using a single MCP.

New Approach for Manufacturing Ti–6Al–4V+40%TiC Metal-Matrix Composites by 3D Printing Using Conic Electron Beam and Cored Wire. Pt. 2: Layered MMC/Alloy Materials, Their Main Characteristics, and Possible Application as Ballistic Resistant Materials

Bilayer samples comprised of hard metal-matrix composite top layer and ductile 10 mm Ti–6Al–4V plate are produced with 3D printing by conical electron-beam method using specially prepared core (powder) wire that allows forming hard top layer of metal-matrix (Ti–6Al–4V) composite (MMC) reinforced by means of fine TiC particles with thickness up to 4 mm. Ballistic tests performed with 7.62×51 AP ammunition show a good ballistic resistance of this protective structure, i.e., it is not perforated. Only minor penetration and partial fracture are occurred exclusively in the surface MMC layer. Either no traces of plastic deformation are found at the boundary with the base layer or inside it that indicates that the MMC layer absorbs the entire impact energy of the projectile. Based on studies of the fine structure and texture of the interface between the layers, a reasonable assumption is made that wavy geometry of MMC layer provides additional deflection and scattering of stress waves generated during impact. Comparing the results of ballistic tests of various metallic materials, it is concluded that the 3D-printed bilayer material consisting of the upper Ti–6Al–4V + 40% TiC layer and the base Ti–6Al–4V layer has an undeniable advantage in ballistic performance when it is tested with cartridges of this type.

Thermoluminescent and Dosimetric Properties of Zirconium Dioxide Ceramics Irradiated with High Doses of Pulsed Electron Beam

Thermoluminescent (TL) properties of monoclinic zirconium dioxide ceramics were studied in order to assess the possibility of their use for measuring high doses (on the order of kGy) of pulsed electron beams (130 keV). Two types of samples were used: those synthesized by sintering in an electric furnace at T = 700–1700 °C and those synthesized in a flow of high-energy electrons (1.4 MeV) with a high power density. Analysis of the X-ray diffraction patterns using the Scherrer method revealed that annealing of ceramics of the first type at T > 1000 °C leads to a significant increase in the size of crystallites, which correlates with a significant increase in the intensity of the TL peak at 390 K. Type 2 ceramics synthesized by the electron beam method have the maximum TL response. Using the peak shape analysis method, the kinetic parameters of TL (activation energy, frequency factor, and kinetic order) were calculated. This study marks the first instance of establishing the patterns of influence of synthesis conditions and crystallite size on their values. The presence of an intense isolated TL peak, the sublinear nature of most dose dependencies, and negligible fading indicate the promise of the ceramics synthesized in this work for measuring high doses (several to tens of kGy).

Excellent Dark/Light Dual-Mode Photoresponsive Activities Based on g-C3N4/CMCh/PVA Nanocomposite Hydrogel Using Electron Beam Radiation Method.

Photocatalytic technology for inactivating bacteria in water has received much attention. In this study, we reported a dark-light dual-mode sterilized g-C3N4/chitosan/poly (vinyl alcohol) hydrogel (g-CP) prepared through freeze-thaw cycling and an in situ electron-beam radiation method. The structures and morphologies of g-CP were confirmed using Fourier infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), solid ultraviolet diffuse reflectance spectroscopy (UV-vis DRS), and Brunauer-Emmett-Teller (BET). Photocatalytic degradation experiments demonstrated that 1 wt% g-CP degraded rhodamine B (RhB) up to 65.92% in 60 min. At the same time, g-CP had good antimicrobial abilities for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 4 h. The shapes of g-CP were adjustable (such as bar, cylinder, and cube) and had good mechanical properties and biocompatibility. The tensile and compressive modulus of 2 wt% g-CP were 0.093 MPa and 1.61 MPa, respectively. The Cell Counting Kit-8 (CCK-8) test and Hoechst33342/PI double staining were used to prove that g-CP had good biocompatibility. It is expected to be applied to environmental sewage treatment and wound dressing in the future.

Nanobubbles and physical-mechanical properties of the Ti-Ni-Ta-Si-based metallic glass surface alloy fabricated on a TiNi SMA substrate by additive thin-film electron-beam method

An additive thin-film electron-beam method for the synthesis of micron-thick surface alloys is a promising method for modifying the surface layers of metallic materials. This method allows to functionalize the surface properties (corrosion resistance, radiopacity, biocompatibility), as well as to improve the physical-mechanical properties. The amorphous Ti-Ni-Ta-Si-based surface alloy (~1.6 μm thick) was synthesized by 10-fold alternation of operations of the deposition of an alloying film (Ti60Ta30Si10 (at. %), ~100 nm thick) and the liquid-phase mixing of the [film/substrate] system using a pulsed low-energy high-current electron beam. Spherical nanobubbles (diameter varies from ~2.5 up to ~50 nm) were observed within the surface alloy. The additional electron-beam treatments were used to reduce the concentration of the nanobubbles. The paper presents the results of the influence of the electron-beam treatments on the concentration and size of the nanobubbles, and their in-depth distribution. It was found that the single-step electron-beam treatment effectively reduced the concentration of the nanobubbles and affected on their size and distribution. The two-step electron-beam treatment almost restored the characteristics of the nanobubbles. The influence of the characteristics of the nanobubbles on the strength and elastic-plastic parameters of the amorphous Ti-Ni-Ta-Si-based surface alloy was revealed. The characteristics of the nanobubbles had a major effect on the elastic-plastic parameters of the surface alloy while the strength parameters remained practically the same. It was found that a purposeful change of the characteristics of the nanobubbles is an effective tool for controlling physical-mechanical properties of the amorphous Ti-Ni-Ta-Si-based surface alloy fabricated on a TiNi SMA substrate.

Comparative Studies of the Structure and Residual Stresses Formed During Tantalum Alloying of TiNi Surface Layers by Ion- or Electron-Beam Method

Comparative Studies of the Structure and Residual Stresses Formed During Tantalum Alloying of TiNi Surface Layers by Ion- or Electron-Beam Method

Solvent-free and low temperature synthesis of chalcogenide Na superionic conductors for solid-state batteries

Sodium chalcogenide ionic conductors are attractive candidates as solid electrolytes (SEs) in solid-state Na metal batteries. They show the advantages of high ionic conductivity of 10−4–10−2 S cm−1 at room temperature and great chemical stability in air. However, simple and efficient approaches for the scalable synthesis of chalcogenide solid electrolytes (SEs) are required. In this work, we report a solvent-free mixing to form dry intermediate products, which are subjected to different treatments (electron-beam assisted method or low temperature heating (≤150 °C)) to produce pure phase of Na3SbS4-ySey (0 ≤ y ≤ 2) chalcogenides. Heavy Se-doping in Na3SbS4 results in the tetragonal-to-cubic phase transition as well as a significant change of Sb-S bonding in Raman spectra. Among all chalcogenide SEs, Na3SbS3Se showed the highest ionic conductivity of 3.75 × 10−4 S cm−1 at room temperature, 47% higher than that of pristine Na3SbS4. Moreover, the Se-dopant also enhanced the electrochemical stability towards Na metal in solid-state batteries. The solid-state Na||FeS2 battery with Na3SbS3Se SE displayed long-term cycling ability up to 1,000 cycles within the voltage window of 1.0–2.7 V and retained a specific discharge capacity of 105 mAh g−1 after 600 cycles. This technique promotes the practical applications of chalcogenide SEs in solid-state Na batteries.

POSSIBILITIES OF USING OPTICAL RADIATION DIFFRACTION MANAGEMENT METHODS ON REFLECTIVE COATINGS OF ARMAMENT AND MILITARY EQUIPMENT FOR ITS PROTECTION AGAINST AMMUNITION WITH SEMI-ACTIVE LASER GUIDANCE SYSTEMS

The article substantiates the need to improve the existent methods of combat defense and combat equipment (DAM) against bombs (guided combat munitions from UAVs, stray combat munitions, etc.)with semi-active laser targeting systems (LSA) on the basis of controlled reflective coatings. Methods of management the diffraction of optical radiation on reflecting coatings are based on applications in coating materials. At the same time, the reflecting properties can be purposefully changed by applying acousto-optical, electro-optical and thermos-optical effects. The acousto-optic method of diffraction control involves the spatial modulation of the beating coefficient in the medium, which is carried out by ultrasonic (acoustic) waves. During the distribution of ultrasound in the reflective coverage (areas of compression and discharge of the material of the waves distribution) appears in the reflective coverage. A purposeful change of descriptions of the acoustic wave leads to the possibility of forming the reflecting phase grating with a given parameter on which it will diffract a radiation. The electro-optical method of management the diffraction of laser radiation is based on the phenomenon of induced anisotropy of media under the influence of a field (electro-optical effect). However, the creation of reflective diffractive elements (coatings)using the electro-optical effect is limited by a number of disadvantages of this method. The thermo-optical method of management light diffraction consists in changing the optical constants of reflective coatings under the influence of temperature. On the basis of the multilayer interference systems (MLIS) with tapes, peak and phase diffraction gratings can be implemented. The use of MLIS coatings with ribbons in the display allows you to implement the functions of selecting and unlocking coatings in the infrared range. The last two methods are of the greatest practical interest since, unlike, the electron-beam method they allow heating a fairly large surface area of the coating. The implementation of diffraction control of optical radiation on the reflective coatings of DAM samples will allow to remove the ammunition control system with semi-active LSA from the working state as a result of the aiming point fluctuation.

Three-Dimensional Control of the Doses by Scanning Method of Electron Beam

Three-Dimensional Control of the Doses by Scanning Method of Electron Beam

Imaging scatterometer for observing in situ changes to optical coatings during air annealing.

Annealing of amorphous optical coatings has been shown to generally reduce optical absorption, optical scattering, and mechanical loss, with higher temperature annealing giving better results. The achievable maximum temperatures are limited to the levels at which coating damage, such as crystallization, cracking, or bubbling, will occur. Coating damage caused by heating is typically only observed statically after annealing. An experimental method to dynamically observe how and over what temperature range such damage occurs during annealing is desirable as its results could inform manufacturing and annealing processes to ultimately achieve better coating performance. We developed a new, to the best of our knowledge, instrument that features an industrial annealing oven with holes cut into its sides for viewports to illuminate optical samples and observe their coating scatter and eventual damage mechanisms in situ and in real time during annealing. We present results that demonstrate in situ observation of changes to titania-doped tantala coatings on fused silica substrates. We obtain a spatial image (mapping) of the evolution of these changes during annealing, an advantage over x ray diffraction, electron beam, or Raman methods. We infer, based on other experiments in the literature, these changes to be due to crystallization. We further discuss the utility of this apparatus for observing other forms of coating damage such as cracking and blisters.