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This work aims to investigate the 64Cu isotope applicability for positron annihilation experiments in in situ mode. We determined appropriate characteristics of this isotope for defect studies and implemented them under aggressive conditions (i.e., elevated temperature, hydrogen environment) in situ to determine the sensitivity of this approach to thermal vacancies and hydrogen-induced defects investigation. Titanium samples were used as test materials. The source was obtained by the activation of copper foil in the thermal neutron flux of a research nuclear reactor. Main spectrometric characteristics (e.g., the total number of counts, fraction of good signals, peak-to-noise ratio) of this source, as well as line-shaped parameters of the Doppler broadening spectrum (DBS), were studied experimentally. These characteristics for 64Cu (in contrast to positron sources with longer half-life) were shown to vary strongly with time, owing to the rapidly changing activity. These changes are predictable and should be considered in the analysis of experimental data to reveal information about the defect structure. The investigation of samples with a controlled density of defects revealed the suitability of 64Cu positron source with an activity of 2–40 MBq for defects studies by DBS. However, greater isotope activity could also be applied. The results of testing this source at high temperatures and in hydrogen atmosphere showed its suitability to thermal vacancies and hydrogen-induced defects studies in situ. The greatest changes in the defect structure of titanium alloy during high-temperature hydrogen saturation occurred at the cooling stage, when the formation of hydrides began, and were associated with an increase in the dislocation density.

The purpose of this work is to implement the positron lifetime and Doppler broadening techniques for the study of hydrogen-induced defects in Zr–1wt% Nb (hereinafter Zr–1Nb) alloy. It was shown that spark cutting is an appropriate instrument to obtain a pair of Zr-1Nb samples with the same hydrogen content for the “sandwich” geometry and does not introduce open-volume defects in them during the cut. The ab-initio calculations were implemented to evaluate the positron annihilation characteristics for expanded crystal lattice, Zr with absorbed hydrogen, Zr-vacancy and Zr-vacancy-hydrogen complexes. The type of defects created in Zr-1Nb alloy loaded with hydrogen from the gas phase up to various hydrogen concentrations was studied. The main types of defects induced by hydrogen loading are vacancy-hydrogen complexes and dislocations. The processes of crystal lattice expansion and hydrogen dissolution in the lattice were studied.

The defect structure and mechanical properties of the samples manufactured from Ti-6Al-4V powder by electron beam melting (EBM) before and after hydrogenation was studied. It has been established that hydrogenation of EBM titanium alloy to a concentration of 470 ppm leads to the formation of titanium γ-hydride, the volume content of which is 2.2%. A further increase in the concentration of hydrogen to 650 ppm is accompanied by a slight increase in the content of the hydride phase, while the proportion of the β phase of titanium increases (to 4.9%). When the hydrogen content is 900 ppm, the fraction of γ hydride decreases and the fraction of the beta phase decreases to 4.2%, and the formation of the hydride phase δ is observed. The introduction of hydrogen leads to a decrease in the wear and an increase in the hardness of EBM Ti-6Al-4V samples. This circumstance is due to the microstructure refinement under the action of hydrogen and the formation of secondary phase precipitates. The hydrogen content increases, the dislocation density and the concentration of hydrogen-vacancy complexes linearly increase, which indicates that hydrogen not only actively interacts with existing defects but also induces the formation of new defects.

This work is devoted to studying the accumulation of hydrogen in titanium coatings to use a completely new concept of hydrogen accumulators based on a system of easily replaceable cartridges. Modern hydrogen accumulators based on magnesium powder have several problems associated with uneven heating during hydrogen desorption. Increasing the efficiency of hydrogen accumulators and the possibility of their reuse and/or repair remains a topical problem. For the analysis of the microstructure of the received titanium coatings, scanning electron microscopy (SEM) was used, the structural-phase state was studied using x-ray diffraction (XRD) analysis. The coatings were hydrogenation by gas-phase saturation at 450&ndash, 550 &deg, C. Increased film thickness reduced the storage capacity of coatings. Besides hydrogenation at 450 &deg, C, 20 &micro, m of titanium coatings accumulated 3.96 wt.%, while 80 &micro, m of coatings accumulated 3.98 wt.%. The chemical composition of the coatings before and after the hydrogenation was controlled using glow-discharge optical emission spectroscopy.

In this work, a laboratory X-ray diffraction complex for in situ investigations of structural phase evolution of materials under gaseous atmosphere and elevated temperatures was developed. The approbation of the complex was carried out using a commercially pure titanium (CP-Ti) powder, zirconium (Zr-1Nb) alloy and electron beam melted Ti-6Al-4V alloy. It was established that hydrogenation of the CP-Ti powder occurred at a temperature of 500 &deg, C and a hydrogen pressure of 0.5 atm, accompanied by the formation of metastable &gamma, titanium hydride (&gamma, TiH) phase. The lifetime of the &gamma, TiH phase was 35&ndash, 40 min. Decomposition of the &gamma, TiH occurred after reaching a temperature of 650 &deg, C as a result of the thermally stimulated desorption of hydrogen. The &alpha, Zr &rarr, &delta, ZrH phase transformation was observed under hydrogenation of the zirconium Zr-1Nb alloy at a temperature of 350 &deg, C and a hydrogen pressure of 0.5 atm. It was revealed that the increase in hydrogenation temperature to 450 &deg, C accelerated this transformation by two times. Hydrogenation of the electron beam melted titanium Ti-6Al-4V alloy at a temperature of 650 &deg, C and hydrogen pressure of 0.5 atm was accompanied by the &alpha, &rarr, &alpha, + &beta, &beta, + &alpha, 2 phase transformations.

The work is devoted to the study of the laws of the formation of a hydride rim in E110 zirconium alloy claddings during gas-phase hydrogenation. The problem of hydrogen penetration and accumulation and the subsequent formation of hydrides in the volume of zirconium cladding tubes of water-cooled power reactors remain relevant. The formation of brittle hydrides in a zirconium matrix firstly, leads to a significant change in the mechanical properties, and secondly, can cause the destruction of the claddings by the mechanism of delayed hydride cracking. The degree of the hydride&rsquo, s effect on the mechanical properties of zirconium cladding is mainly determined by the features of the hydride&rsquo, s distribution and orientation. The problem of hydride rim formation in zirconium alloys with niobium is quite new and poorly studied. Therefore, the study of hydride rim formation in Russian zirconium alloy is important and necessary for predicting the behavior of claddings during the formation of the hydride rim.

Many researchers have carried out experimental research and theoretical analysis on hydrogen storage in carbon nanotubes (CNTs), but the results are very inconsistent. The present paper reviewed recent progress in improving the hydrogen storage properties of CNTs by various modifications and analyzed the hydrogen storage mechanism of CNTs. It is certain that the hydrogen storage in CNTs is the result of the combined action of physisorption and chemisorption. However, H2 adsorption on metal-functionalized CNTs still lacks a consistent theory. In the future, the research of CNTs for hydrogen adsorption should be developed in the following three directions: (1) A detailed study of the optimum number of metal atoms without aggregation on CNT should be performed, at the same time suitable preparation methods for realizing controllable doping site and doped configurations should be devised; (2) The material synthesis, purification, and activation methods have to be optimized; (3) Active sites, molecular configurations, effectively accessible surface area, pore size, surface topology, chemical composition of the surface, applied pressure and temperature, defects and dopant, which are some of the important factors that strongly affect the hydrogen adsorption in CNTs, should be better understood.

As a clean and ideal secondary energy source, hydrogen energy has attracted widespread attention from all countries in the world. Hydrogen storage technology is a crucial technology for the commercial application of hydrogen energy. However, none of the candidate materials developed so far has satisfied the United States Department of Energy (DOE) target yet. Compared with the single catalytic effect, the synergistic effect in composite materials is considered a more effective way to achieve the best hydrogen storage properties by controlling the hydrogen storage properties of both the matrix and the filler. In this article, based on the understanding of new aspects of synergistic behavior between metal-organic frameworks (MOFs) support and doped hydride-forming metal nanoparticles, we revealed the prospects of hybrid materials composed of MOFs and hydride-forming metal nanoparticles for light-duty vehicle hydrogen storage.

Inner-side coatings have been proposed as a complementary solution within the accident tolerant fuel (ATF) framework, to provide enhanced protection for the nuclear fuel cladding. Unlike external surface, the degradation of irradiated internal cladding surface has not been studied extensively. Fission fragments produced during the fission of nuclear fuel is one of the key players in this degradation. This study aimed to estimate the minimum thickness of the thin chromium film, required to protect the inner side of the nuclear fuel cladding. The approach used is based on a set of calculations, of Ion ranges and damage profiles, for a group fission fragments, using the TRIM code. The calculation results were verified by comparison with the experimental data associated with the phenomena of the inner cladding degradation of thermo-releasing elements. The recommended minimum thickness for such a film was found to be 9 microns. Calculations also showed that chromium metal has a greater stopping power compared to the zirconium-based alloy E110, which indicates an increased ability of chromium to withstand exposure to energetic fission fragments during reactor operation.

The hydrogen sorption and desorption behavior in spherical powder of pure titanium used for additive manufacturing have been investigated. The dependencies of oxide dissolution time and hydrogen sorption rate on pressure and temperature have been obtained. The main regularities of phase formation in titanium powder during hydrogenation until hydrogen concentration 4 wt% have been showed. The peculiarities of hydrogen desorption from the spherical powder of titanium with hydrogen concentration 4 wt% have been demonstrated.

Sorption properties of titanium alloy VT1-0 coated by nickel layer using dc magnetron sputtering were investigated in this paper. The crystalline structure of the coating as well as evaluation of its thickness was analyzed by X-ray diffraction in grazing incidence geometry. It was revealed that the nickel coating significantly increases the hydrogen sorption rate of titanium alloy compared to pure titanium covered with its original oxide layer. Hydrogen sorption rate reduces approximately from 10 −3 to 10 −4 wt.%/s with increasing the nickel thickness from 1 to 2.6 μm, respectively. Hydrogen sorption kinetics strongly depends on the hydrogenation parameters. The increase of both temperature in the range of 350–550 °C and hydrogen pressure from 1 to 2 atm leads to increase of hydrogen sorption rate.

Zirconium alloys, such as Zr-1Nb are widely used as cladding materials for nuclear fuel elements of light water reactors. Hydrogen embrittlement problem causes degradation of these parts of nuclear reactors. It is known, that hydrogen uptake causes changes in microstructure and defect structure of metals. The aim of this work is study of Zr-1Nb alloys’ defect structure after hydrogen saturation up to the concentration of 600 ppm. Saturation of hydrogen was carried out from the gas phase under high temperature and pressure. This study reveals the increase of average positron lifetime with the increase of hydrogen concentration. Value of the average positron lifetime achieves plateau when the concentration of hydrogen is about 600 ppm. Also the following effects were detected in the material after hydrogen uptake up to different concentrations: crystal lattice expansion, dislocations and vacancy-like defects formation, as well as the defect-hydrogen complexes formation.

The results of hydrogen sorption and desorption processes investigation at commercially pure titanium alloy during hydrogenation at gas atmosphere are shown in this article. Titanium alloy hydrogenation at temperatures 350, 450 и 550 °С leads to δ-hydrides formation in samples’ volume. Hydrogen sorption rates were calculated on the linear parts of sorption curves and equal to 0.15·10-4 wt%/s at 350 °C, 0.86·10-4 wt%/s at 450 °C, 1.55·10-4 wt%/s at 550 °C. Phase transition in titanium-hydrogen system during thermally stimulated hydrogen desorption investigation by the means of short-wave diffraction of synchrotron radiation shows hydrides dissociation until 520-530 °C. Then α→β transition takes place until 690-720 °C and at this temperatures the phase transformation ends and additional hydrogen desorption peak appears in thermally stimulated hydrogen desorption curve. Defect structure at different hydrogen concentration investigation by the means of electron-positron annihilation techniques shows that hydrogen penetration into titanium leads to crystal lattice expansion. It initiates vacancy-type defects formation which reacts with hydrogen and forms defect-hydrogen complexes.

Titanium and its alloys are promising materials for hydrogen storage. However, hydrogen penetration accompanies the exploitation of hydrogen storage alloys. In particular, hydrogen penetration and accumulation in titanium alloys changes their mechanical properties. Therefore, the research works of such materials are mainly focused on improving the reversibility of hydrogen absorption-liberation processes, increasing the thermodynamic characteristics of the alloys, and augmenting their hydrogen storage capacity. In the process of hydrogenation-dehydrogenation, the formed defects both significantly reduce hydrogen storage capacity and can also be used to create effective traps for hydrogen. Therefore, the investigation of hydrogen interaction with structural defects in titanium and its alloys is very important. The present work, the hydrogen-induced formation of defects in the alloys of commercially pure titanium under temperature gas-phase hydrogenation (873 K) has studied by positron lifetime spectroscopy and Doppler broadening spectroscopy. Based on the evolution of positron annihilation parameters τf, τd, their corresponding intensities If, Id and relative changes of parameters S/S0 and W/W0, the peculiarities of hydrogen interaction with titanium lattice defects were investigated in a wide range of hydrogen concentrations from 0.8at% to 32.0at%.

Magnesium-based hydrogen storage materials are considered to be one of the most promising solid-state hydrogen storage materials due to their large hydrogen storage capacity and low cost. However, slow hydrogen absorption/desorption rate and excessive hydrogen absorption/desorption temperature limit the application of magnesium-based hydrogen storage materials. The present paper reviews recent progress in improving the hydrogen storage properties by element substitution and additives. Ball milling is the promising technology for preparing magnesium-based hydrogen storage materials. The research and development of approaches for modifying magnesium-based hydrogen storage materials prepared by ball milling is systematically expounded. It is concluded that ball milling can significantly improve the kinetic and electrochemical properties of magnesium-based hydrogen storage materials and increase the hydrogen storage capacity. In the future, the research of magnesium-based hydrogen storage materials should be developed in terms of hydrogen storage mechanism, computer design of materials and development of a more optimized catalytic system.

In this study, the effect of additional heat treatment on the microstructure and mechanical properties of the titanium Ti-6Al-4V alloy produced by the method of electron beam melting was studied. It has been established that additional heat treatment of samples allows reducing the friction coefficient and decreasing internal stresses in the material. At the same time, a decrease in microhardness, as well as the strength and plastic characteristics of EBM Ti-6Al-4V alloy, is observed. Simultaneously, heat treatment leads to a reduction in the rate of hydrogen accumulation by EBM Ti-6Al-4V alloy during saturation from a gaseous medium.

This paper describes the methodology for conducting experiments to study hydrogen diffusion through metal membranes using a specially designed diffusion chamber of an automated gas reaction controller complex. This complex allows experiments to study hydrogen diffusion with the following parameters: the inlet hydrogen pressure is up to 50 atmospheres, and the temperature in the chamber is from 30 &deg, C to 1000 &deg, C. The size of the samples is limited to a diameter of 10 mm and a thickness of 100 &mu, m. The method for calculating the diffusion coefficient based on the Fick equation is also described. When studying hydrogen diffusion through a sample of Zr&ndash, 1Nb alloy with nickel film deposited at the temperature of 550 &deg, C, it was noted that phase transformations can be observed on the diffusion curve.

In this study, the distributions of dislocation density with hydrogen concentration in titanium VT1-0 were obtained. The samples with different hydrogen concentrations was carried out by using the Sieverts method. The dislocation densities were obtained by using the full width at height medium calculations from the XRD results of Gaussian approximation fitting. For accurate calculation of the dislocation density in titanium alloys, the double-line separation phenomenon of the XRD results and the variation of the Burgers vector in different lattice directions were considered. The phenomenon of the double-line separation is more evident when the diffraction angle 2θ is larger than 40°. The mean value of dislocation density for the different hydrogen concentrations is about 1013 ∼ 1014 m−2. Moreover, as the increases of hydrogen content in the titanium alloy, the dislocation density also increases.

Barium aluminates have been obtained by the method of continuous precipitation at different values of pH. The method of thermal analysis showed that the main mass losses which are connected with dehydration processes occur in the temperature interval from 50 °C to 100 °C and from 150 °C to 200 °C. In addition, mass loss occurs in the temperature interval from 780 °C to 1000 °C which can indicate barium aluminate formation. XRD analysis was applied to determine phase composition of obtained substance and showed formation of Ba1.17Al10.67O17.17 and BaAl2O4 at pH 6.5; 7.0 and 7.5 respectively. Significant influence of pH on precipitation composition has not been detected.

Effect of hydrogen on the structural and phase state of the fine-grained and submicrocrystallinestructure of two-phase (alpha + beta) titanium Ti-6Al-4V alloy was investigated by the methods of electron microscopy and X-ray diffraction analysis. Hydrogenation is found to result in minor structural and phase changes both in fine-grained and submicrocrystalline samples.The use of electron beam exposure combined with heating for hydrogen release in the Ti-6Al-4V alloy is shown to reduce degassing time and decrease the hydrogen concentration to the values closed to the engineering standards for the Ti-6Al-4V alloys.

Hydrogen sorption-desorption processes by zirconium alloy Zr-1Nb was investigated in this article. Sievert apparatus was used for investigation of hydrogen interaction with material. It was shown that hydrogenation at gas atmosphere at 350, 450 and 550 °C temperatures leads to the δ-hydride formation in all material volume. Hydrogen sorption rates were calculated on the linear parts of sorption curves and equal to 0.5·10-4 wt%/s at 350 °C, 9.5·10-4 wt%/s at 450 °C and 23.1·10-4 wt%/s at 550 °C. Short-wave diffraction of synchrotron radiation was used for investigation of hydrides dissociation during heating. Hydrides dissociation formed after hydrogenation at gas atmosphere occurs at temperature 522-540 °C. Further temperature increasing leads to β-phase appearance which indicates α to β phase transition at zirconium.

The influence of hydrogen sorption-desorption cycles on defect structure of Zr-1Nb alloy was investigated. Specimens were hydroganated from gas atmosphere at temperature 500 °C and pressure 2 atm up to the hydrogen concentration equal to 0.05 wt.% for each cycle. The hydrogen concentration during saturation was determinate by the volumetric method. Then samples were annealed at temperature 900 °C with the heating rate of 4 °C/s. The lattice defects were studied by means of positron lifetime spectroscopy (PLS) and doppler broadening spectroscopy (DBS). New experimental data about the evolution of the average positron lifetieme τavg, as well as the relative changes in the parameters S, W depending treatment stage in Zr-1Nb alloy during thermo hydrogen proccessing was obtained.

Titanium and zirconium are used in many fields such as chemical, aircraft and nuclear industries. Hydrogen penetration and accumulation in titanium and zirconium alloys leads to the hydrogen-induced embrittlement. The study of hydrogen accumulation and distribution as well as phase transitions in zirconium alloy Zr1%Nb and commercially pure titanium alloy during the gas-phase hydrogenation is motivated by looking for a way to prevent materials from embrittlement. Gas-phase hydrogenation and thermo-stimulated desorption methods were used for hydrogen sorption and accumulation processes investigation. Synchrotron XRD method was applied for in situ investigation of phase transitions during heating of hydrogen saturated materials. Measurements were performed using SR from the VEPP-3 storage ring.

The zirconium alloy (Zr1%Nb) samples with a micron-thick nickel layer were investigated for hydrogen sorption ability. Hydrogenation was carried out by gas phase method at temperatures of 350, 450 and 550° C. Hydrogen pressure in chamber was 1 atm. Hydrogen sorption curves were obtained on the automated complex Gas Reaction Controller. In situ X-ray diffraction measurements of the process of hydrogen saturation of samples were carried out at the station “Precision diffractometry» at Siberian Synchrotron and Terahertz Radiation Center of the Budker Institute of Nuclear Physics. Hydrogen absorption rate by Zr1%Nb alloy increases by order of magnitude with increasing temperature. The phase transitions significantly affect the rate of hydrogen absorption at constant temperature. Measurements were performed using SR from the VEPP-3 storage ring.

Normally, the Nernst voltage calculated from the concentration of the reaction gas in the flow channel is considered to be the ideal voltage (reversible voltage) of the hydrogen-oxygen fuel cell. The Nernst voltage loss in fuel cells in most of the current literature is thought to be due to the difference in concentration of reaction gas in the flow channel and concentration of reaction gas on the catalyst layer at the time as when the high net current density is generated. Based on the Butler–Volmer equation in the hydrogen-oxygen fuel cell, this paper demonstrates that Nernst voltage loss caused by concentration difference of reaction gas in the flow channel and reaction gas on the catalyst layer at equilibrium potential. According to the relationship between the current density and the concentration difference it can be proven that Nernst voltage loss does not exist in hydrogen-oxygen fuel cells because there is no concentration difference of reaction gas in the flow channel and on the catalytic layer at equilibrium potential when the net current density is zero.

Titanium dioxide film is one of the most promising self-cleaning materials. The self-cleaning performance is directly related to the photocatalytic activity and surface wettability, which, in turn, depends on the TiO2 film structure parameters. Nitrogen-doping and post annealing are commonly used for TiO2 film treatment. The present paper addresses the mechanisms of N-doping and annealing induced TiO2 film structure transition, band gap narrowing and wettability transition. It is shown that N-doping combined with annealing leads to anatase → rutile phase transition, formation of hierarchical topography, change of surface chemical composition, and consequently results in reduction of band gap energy and water contact angle. N-doping level and N-linkages are found to significantly affect the structure/properties of annealed TiO2 and N-doped TiO2 films. The proposed mechanisms might help optimize TiO2 film synthesis and post treatment procedures. Moreover, annealed N-doped TiO2 film with highest N-content, simultaneously exhibiting anatase-rutile polycrystalline structure, high roughness, as well as lowest band gap energy and water contact angle, is supposed to present optimal self-cleaning performance.

Currently, standard samples with high hydrogen concentrations that meet the requirements of hydrogen extraction in an inert atmosphere are not currently available on the market. This article describes the preparation of Ti-H standard samples and the calibration of RHEN602, a hydrogen analyzer, using LECO (LECO, Saint Joseph, MI, USA). Samples of technically pure titanium alloy were chosen as the material for sample production. The creation procedure includes five main steps: sample preparation (polishing to an average roughness of 0.04 &mu, m using sandpaper), annealing, hydrogenation, maintenance in an inert gas atmosphere, and characterization of the samples. The absolute hydrogen concentration in the samples was determined by two methods: volumetric and mass change after the introduction of hydrogen. Furthermore, in-situ X-ray diffraction, temperature programmed desorption (TPD) analysis, and thermogravimetric analysis were used during measurements to investigate the phase transitions in the samples. As a result of this work, a series of calibration samples were prepared in a concentration range up to 4 wt % hydrogen, optimal parameters for measuring high concentrations of hydrogen. The calibration line was obtained and the calibration error was 10%.

Influence of manufacturing parameters (beam current from 13 to 17 mA, speed function 98 and 85) on microstructure and hydrogen sorption behavior of electron beam melted (EBM) Ti-6Al-4V parts was investigated. Optical and scanning electron microscopies as well as X-ray diffraction were used to investigate the microstructure and phase composition of EBM Ti-6Al-4V parts. The average alpha lath width decreases with the increase of the speed function at the fixed beam current (17 mA). Finer microstructure was formed at the beam current 17 mA and speed function 98. The hydrogenation of EBM Ti-6Al-4V parts was performed at the temperatures 500 and 650 degrees C at the constant pressure of 1 atm up to 0.3 wt %. The correlation between the microstructure and hydrogen sorption kinetics by EBM Ti-6Al-4V parts was demonstrated. Lower average hydrogen sorption rate at 500 degrees C was in the sample with coarser microstructure manufactured at the beam current 17 mA and speed function 85. The difference of hydrogen sorption kinetics between the manufactured samples at 650 degrees C was insignificant. The shape of the kinetics curves of hydrogen sorption indicates the phase transition alpha(H)+beta(H)->beta(H).

The mechanical properties of the hydrogenated zirconium alloy Zr-1Nb are studied under different conditions for hydrogen removal by an electron beam and thermal heating. The mechanical testing of zirconium samples is analyzed during hydrogenation and irradiation with a low energy electron beam. The plasticity of the samples is shown to be increased during the radiation stimulation of hydrogen removal from zirconium by even a weak electron beam. In this case, the tensile strength (ultimate strength) is practically not changed.

In this paper, phase transitions and microstructure evolution in titanium Ti-6Al-4V alloy parts produced by electron beam melting (EBM) under hydrogenation was investigated. Hydrogenation was carried out at the temperature of 650 °C to the absolute hydrogen concentrations in the samples of 0.29, 0.58, and 0.90 wt. %. Comparative analysis of microstructure changes in Ti-6Al-4V alloy parts was performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Furthermore, in-situ XRD was used to investigate the phase transitions in the samples during hydrogenation. The structure of Ti-6Al-4V parts produced by EBM is represented by the α phase plates with the transverse length of 0.2 μm, the β phase both in the form of plates and globular grains, and metastable α″ and ω phases. Hydrogenation to the concentration of 0.29 wt. % leads to the formation of intermetallic Ti3Al phase. The dimensions of intermetallic Ti3Al plates and their volume fraction increase significantly with hydrogen concentration up to 0.58 wt. % along with precipitation of nano-sized crystals of titanium δ hydrides. Individual Ti3Al plates decay into nanocrystals with increasing hydrogen concentration up to 0.9 wt. % accompanied by the increase of proportion and size of hydride plates. Hardness of EBM Ti-6Al-4V alloy decreases with hydrogen content.

Experimental Stand for Testing Electrochemical Permeation (STEP) of hydrogen through metal foils was constructed and described in this paper. Hydrogen diffusion coefficients in different metal foils at room temperature can be determined by using STEP. Influence of pulsed electron beam irradiation on hydrogen diffusion coefficient in zirconium alloy E110 was investigated. It was established that treatment by pulsed electron beam with the energy density of 18 J/cm2, by three impulses with duration 50 μs leads to a decrease in the diffusion coefficient of hydrogen on the order of one. This is due to the fact that structure with more branched crystals’ boundary formed after irradiation and such structure is effective trap for hydrogen. Also there is formation of protective oxide film after irradiation.

This paper is devoted to the defect structure study of commercially pure titanium after hydrogen sorption-desorption cycles by means of positron lifetime (PL) and Doppler broadening spectrometry. Material was loaded with hydrogen from the gas phase till the concentration of hydrogen reached the value of 0.05 wt.% for each cycle. The essential changes in the positron annihilation characteristics of the sample are occurred after the each stage of treatment.

Hydrogen sorption, structural phase state and mechanical properties after hydrogenation of zirconium alloy Zr1%Nb with ZrO2 and TiO2 coatings were investigated. It has been established that ZrO2 coating reduces the rate of hydrogen sorption by zirconium alloy Zr1%Nb in comparison with the initial material at hydrogen saturation temperature 450 °С.

The experimental study of the structure of commercially pure titanium after saturation with hydrogen from the gas phase by means of positron lifetime spectroscopy (PLS) and Doppler broadening spectroscopy (DBS) was carried out. In the result of penetration and accumulation of hydrogen, significant changes of annihilation characteristics occurred due to the defect structure changing. The investigated samples contained hydrogen in concentrations varying from 0 to 0.961 wt.%. Several stages of hydrogen interaction with the metal structure were revealed.

In this work the goal was to study the behavior of titanium-hydrogen system with hydrogen concentration of 1 wt. % at high temperature vacuum annealing by means of positron lifetime (PL) spectroscopy and electrical resistivity measurements. The range of hydrogen concentrations under investigation requires the γ phase formation. The study is related with the X-ray diffraction (XRD) and thermal desorption spectra (TDS) analysis. The registered positron lifetime spectra were analyzed by multiexponential decomposition into two components. Correlation of changes of the parameters of the PL spectrum and the electrical resistivity is revealed in this paper.

This paper presents experimental results in study of hydrogen redistribution in technically pure titanium alloy under X-ray exposure at room temperature. It is demonstrated that X-ray exposure to titanium with hydrogen affects hydrogen diffusion and redistribution from the surface area to the depth of the samples irrespective of hydrogen condition in titanium: in hydride form or dissolved state. Increase of the exposure time increases the amount of hydrogen redistributed. Hydrogen desorption during irradiation by X-rays at room temperature does not happen.

This paper presents experimental results of study of hydrogen accumulation in technically pure titanium alloy at saturation from gas atmosphere. Automated complex Gas Reaction Controller has been used for hydrogen saturation from gas atmosphere. Temperatures increasing from 350 °C to 500 °C allow increase hydrogen sorption process and as a result significantly increase hydrogen concentration in technically pure titanium alloy. At hydrogen saturation from gas atmosphere at temperature 500 °C increasing of saturation time from 10 minutes to 120 minutes leads to hydrogen concentration increasing from 0.1 wt.% to 1 wt.% and increasing of hydrides volume content throughout the samples. The activation energy for hydrogen evolution has been estimated by thermal desorption spectroscopy method by equal 102 kJ/mol.

Mg-based hydrogen storage materials are considered to be one of the most promising solid-state hydrogen storage materials due to their large hydrogen storage capacity and low cost. However, slow hydrogen absorption/desorption rate and excessive hydrogen absorption/desorption temperature limit the application of Mg-based hydrogen storage materials. The present paper reviews the advances in the research of Mg-based hydrogen storage film in recent years, including the advantage of the film, the function theory of fabricating method and its functional theory, and the influencing factors in the technological process. The research status worldwide is introduced in detail. By comparing pure Mg, Pd-caped Mg, non-palladium capped Mg, and Mg alloy hydrogen storage films, an ideal tendency for producing Mg-based film is pointed out, for example, looking for a cheap metal element to replace the high-priced Pd, compositing Mg film with other hydrogen storage alloy of catalytic elements, and so on.

The gradient Cr-Zr layer was formed onto Zr-1Nb substrate by magnetron sputtering of chromium and zirconium targets and ion mixing (Ar+ with 25 keV). The distribution of Cr and Zr elements in the deposited coatings was measured by using a glow discharge optical emission spectroscopy. The optimal ion fluence onto the substrate was 8×1019 ion/m2. At higher ion dose, the intensive sputtering of the deposited coating was observed.

Microstructure changes of commercially pure titanium in a wide range of hydrogen concentrations from 0.8 at.% to 32.0 at.% were studied by means of positron lifetime spectroscopy and Doppler broadening spectroscopy. We have obtained new experimental data on the evolution of positron annihilation parameters τ f , τ d and their corresponding intensities I f , I d, as well as relative changes of parameters S / S 0 and W / W 0 depending on the hydrogen concentration in commercially pure titanium after gas-phase hydrogenation at 873 K. Results suggest that the hydrogenation of Ti samples up to concentrations of 1.31–2.27 at.% and subsequent cooling to a room temperature leads to the formation of vacancies and vacancy clusters. Further increase of the hydrogen concentration up to 32.0 at.% leads to the interaction of hydrogen with these defects and the formation of “cluster-hydrogen” and “vacancy-hydrogen” complexes.

Optimal operating parameters for the study of titanium-hydrogen system with the help of glow discharge optical emission spectroscopy have been selected. Hydrogen distribution from the surface to the depth in technically pure titanium alloy after electrochemical hydrogen saturation has been studied.

The paper investigates the effect of hydrogenation towards the concentration of 0.33 wt % on the structural and phase state and the deformation process development during tension of the ultrafine-grained Zr–1 wt % Nb alloy (hereinafter Zr-1Nb) at the temperature range of 293–973 K. Hydrogen presence in the alloy in solid solution and hydride precipitates are found that results in an increase of its strength and plastic characteristics at room temperature. At elevated temperatures hydride dissolution activates dislocation motion that leads to strength characteristics reduction and to rise of deformation-to-failure.

Investigation of hydrogen accumulation and distribution in zirconium alloy Zr1Nb after electrochemical and gas-phase hydrogenation was carried out. The hydride rim with sufficient thickness could not be obtained by electrolytic saturation. The hydrogen sorption rates of zirconium alloy at different temperatures were calculated: 1.65 × 10−4 wt %/min at 350°C, 2.4 × 10−2 wt %/min at 450°C, 7.3 × 10−2 wt %/min at 550°C. The decrease of cooling rate from 10 to 2°C/min after gas-phase hydrogenation lead to increased thickness of the hydride layer from 50 to 59 µm.

This work is focused on the investigation of hydrogen sorption behavior by zirconium alloy Zr1Nb with different surface states. Zirconium alloy samples in initial state, after ion cleaning with subsequent nickel deposition and after treatment by Low Energy High Current Pulsed Electron Beam (LEHCPEB) were hydrogenated at constant pressure and different temperatures. Hydrogen sorption rates as well as the energy of hydrogen adsorption by zirconium alloy with different surface states have been evaluated. It was shown, that ion cleaning with subsequent nickel deposition leads to the hydrogen sorption rate increasing at temperatures 350 – 550 °C, while the energy of hydrogen adsorption by zirconium alloy reduces on 15%. Modification by LEHCPEB leads to the hydrogen sorption rate decreasing at temperatures 350 – 550 °C, while the energy of hydrogen adsorption by zirconium alloy grows on 15%.