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The results of studies of the relationship between the ionic and electronic subsystems of metals are presented. The technique of thermo-EMF measurement on samples made of titanium alloy and steels is used. As shown, as a result of various methods of finishing treatments, the thermoelectric characteristics of metals change. The detected patterns can be used to optimize the processes of parts' treatment and to select the part material for efficient operation under given load conditions. The results of the study suggest that the main influence on the thermo-EMF is determined by the value of the stress--strain state of the structure of the metal sample. [ABSTRACT FROM AUTHOR]

The features of formation of the structure, composition and certain mechanical properties of layered materials based on titanium and its alloys during melting by the electron-beam cold-hearth melting technique are considered. The influence of composition in two-layer structures Ti64 (Ti–6Al–4V)/LCB (low-cost beta Ti–1.5Al–6.8Mo–4.5Fe) and Ti64/Ti5553 (Ti–5Al–5V–5Mo–3Cr), as well as 4-layer Ti5553/Ti64/c.p.Ti (commercial purity titanium)/Ti64 is studied. The processes of formation of transition layers at the boundaries between alloys after both the smelting and the subsequent deformation by rolling, as well as after heat treatments, are studied. A relationship is established between the composition and the formed microstructure, on the one hand, and hardness, strength, ductility, and fracture under 3-point bending, on the other hand. A comparison of the titanium-layered materials produced by this method with the results provided by other technological approaches is carried out, and the advantages of the proposed technology are shown.

Six samples with holes made from high-strength titanium alloy VT-22, which have passed fatigue tests, were studied. The tests were conducted on samples whose surfaces were restored by inert-gas arc surfacing using SP-15 alloy filler wire. Obtained results confirm a significant improvement in the deposited layer structure and a reduction in the negative impact of welding defects. Subsequent local heat treatment (LHT) markedly enhanced the mechanical properties of the samples in the weld zone. Samples of Group 2, which had relatively uniform microhardness in the heat-affected zone (HAZ), after LHT demonstrated high resistance to failure, unlike samples of Group 1, which showed significant microhardness variations in the HAZ. Noncompliance with LHT modes for Group 1 samples resulted in six times reduction in service life compared to Group 2. The detected surface defects of the holes in Group 1 samples negatively affected the crack initiation rate. The obtained results emphasize the importance of adhering to specified parameters of surfacing, final part treatment, and LHT modes to enhance the efficiency and reliability of the restoration procedure. 11 Ref., 5 Tabl., 11 Fig. [ABSTRACT FROM AUTHOR]

The structure of the base metal and weld metal after electron-beam welding (EBW) of the intermetallic titanium alloy Ti−28Al−7Nb−2Mo−2Cr (wt.%) obtained by the electron-beam melting method is studied. The macrostructure of the Ti−28Al−7Nb−2Mo−2Cr alloy ingot is characterized by grains close to equiaxed with a grain size of 8–9 points. As shown, the microstructure of the cast metal of the Ti−28Al−7Nb−2Mo−2Cr alloy consists of a matrix bright γ-phase alternating with sections of a two-phase (γ + α2) lamellar structure up to 50 µm in size, with a lamellae thickness of about 1 µm, and of the ordered β-phase, which forms a mesh pattern against the background of the matrix. As established, the intragranular structure of the metal of the welded joint after EBW with local heat treatment (LHT) differs from the structure of the base metal and consists of small (up to 20 µm) areas with a (γ + α2) lamellar structure against the background of a light matrix γ-phase with a network of elongated particles of 30−80 µm long and 1−3 µm thick. [ABSTRACT FROM AUTHOR]

xBeam 3D metal printing is the most modern method of additive technologies for obtaining blanks by using of titanium alloy TI-6AL-4V metal wire as a base material. The lack of sufficient numbers of studies on the turning blanks obtained by additive technologies prompted the investigation of turning features in particular the influence of increasing cutting speed on the cutting forces, tool temperature, and stress localization on the cutting edge and chip formations by using Third Wave AdvantEdge for simulations. In metal turning, the study of parameters such as tool wear, cutting forces and temperature during the cutting process is complex and expensive. Therefore, computer simulation can be used to predict the required results by selecting the right cutting parameters, materials and cutting tools during the design phase, thus avoiding unnecessary material costs in the future. This article presents the results of a study using the Ad-vantEdge simulation. A square insert with a 0° back angle made of a cemented tungsten carbide (WC) was selected as the cutting tool. The cutting mode parameters were determined analytically using a catalogue. In this study, the feed rate and depth of cut were not changed, and the cutting speed was set in the range of 45 m/min, 55 m/min and 65 m/min. The feed rate was 0.2 mm/rev and the depth of cut was 1 mm. The machining length was 10 mm. Also, the paper contains graphs of cutting forces and tool temperature versus the length of cutting under the influence of increasing cutting speed. The results show that as the cutting force increases, the cutting temperature increases accordingly, but the cutting force remains unchanged and tends to stable values, which confirms the effect of workpiece softening, which facilitates material removal. The distribution of peak stress values on the front surface of the insert increases deeper into the tool. It was found that continuous chips are formed at low cutting speeds, while at high cutting speeds, chips are torn off due to higher temperatures. The results obtained can be used to research of the cutting process and search for the optimal range of cutting modes, which allows evaluating the wear of the cutting tool, its premature failure, and the efficiency of the cutting process. [ABSTRACT FROM AUTHOR]

The purpose of this work is to select a technology for joining platinum foil and titanium, as well as to develop welding modes. The analysis showed that diffusion welding of platinum foil with titanium alloys over a contact area of more than 1000 mm², ensuring continuous penetration and maintaining the original dimensions of the platinum foil requires additional research. Analysis of the platinum-titanium system shows insignificant solubility of titanium in low-temperature modification platinum and higher solubility in high-temperature modification of titanium. Intermetallic compounds Ti3Pt, TiPt, TiPt3 are also formed. The use of fusion welding will lead to the formation of all of the listed phases in the molten zone. It is not possible to regulate their length. The use of diffusion welding in a vacuum makes it possible to regulate the phase composition by changing the welding parameters. To study the phase composition of the platinum-titanium diffusion zone, the following techniques were used: metallographic analysis; X-ray diffraction analysis; X-ray microspectral analysis; electron microscopic analysis. Microstructural studies were carried out on cross-sectional samples at magnifications x500, x4000. Microstructural studies were carried out on cross-sectional samples at magnifications x500, x4000. The detailed structure of diffusion zones was studied using a scanning electron microscope (SEM). The determination of the phase composition of diffusion zones was carried out using the DRON-1.5 installation. Analysis was carried out to identify phases and phase mixtures. Micro-X-ray spectral analysis was carried out on a Cameca device using the scanning method and determining the composition by elements with a distance between points of 2 μm in the direction perpendicular to the welding surface. The formation of the welding zone is determined by diffusion processes and affects the strength of the joint. The holding time is the most significant factor determining the degree of development of diffusion processes.

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.

In this paper, a new approach for additive manufacturing metal-matrix composites based on Ti–6Al–4V titanium alloy reinforced with titanium carbide particles, as well as layered structures consisted of such composite and Ti–6Al–4V alloy layers is considered. The approach is based on 3D printing with a conical electron beam using a special cored wire, whose composition corresponds to metal-matrix composite. The issues of production such a wire, the features of the 3D printing process, when using it, as well as the features of formation of the microstructure and phase composition of the printed composite material are described. The issues of titanium-carbide particles’ wetting with Ti–6Al–4V melt during process of 3D printing, as well as possible thermogravitational effects (floating or drowning) for solid TiC particles within the melt are considered in detail with additional experiments. The influence of individual components of the wire composition on the formation of the microstructure and its uniformity over the cross section of the printed layer is shown. The possibility of controlling the formation of homogeneous structural state and obtaining sufficiently high values of the hardness (of above 600 HV) of the metal-matrix composite layer printed on the Ti–6Al–4V baseplate is shown.

The paper presents the results of experimental studies of the wear process of detonation coatings and counterbodies and compares them with other types of coatings, obtaining wear characteristics. The characteristics of wear of coatings are described in an analytical form, as well as the results of the study of tribological structures. The tribotechnical characteristics of detonation coatings are determined, taking into account the properties of dissipative structures that are self-formed in contact with friction. The effectiveness of the method of researching the process of wear of detonation coatings has been determined. It has been established that when coatings are rubbed against chrome, the total wear of the friction pair is significantly less than when rubbed against bronze. This is due to the best tribotechnical properties of chromium in the experimental field. The coefficient of friction of electrochemical chromium coatings is of the same order as when rubbing on bronze. The total intensity of wear of the coating and the counterbody when rubbing against chrome is somewhat lower than when rubbing against bronze. Since tribological structures are formed from complex oxides, asphaltenes, cokes, etc. during friction of coatings on chrome alloy VT-22, therefore the tribotechnical characteristics of such systems are somewhat lower than in systems that include bronze. [ABSTRACT FROM AUTHOR]

Properties of welded joints of VT19 and Ti–2.8Al–5.1Mo–4.9Fe titanium pseudo-β-alloys and complex Т120 titanium (α+β)-alloy, produced by electron beam and argon-arc welding and after several kinds of heat treatment (annealing, regulated annealing, quenching in water, delayed cooling) were studied. In addition to reliable protection of welded joints, another advantage of the technology of electron beam welding of titanium and alloys on its base is the possibility of performing local preheating and further heat treatment in the vacuum chamber. A quality criterion was proposed in order to compare the properties of welded joints in as-welded condition and after additional heat treatment. It was determined that performance of electron beam welding using local heat treatment and preheating, as well as making the joints by argon-arc welding using filler material, which allows lowering by 10…20 % the amount of alloying elements in the weld metal, compared to base metal, ensures a high quality of welded joints of high-strength titanium pseudo-β-alloys in as-welded condition. [ABSTRACT FROM AUTHOR]

Natural metal composite materials represent a promising class of modern structural materials that need to be welded. Such materials can be welded by fusion, as has been established with the Ti-TiB alloy as an example. The enhanced operational properties of such materials are determined by the microstructure, which is characterized by the presence of microfibers of borides, carbides, or silicides in the metal matrix. To preserve the mechanical properties of materials in a welded joint, it is necessary to ensure the formation of reinforcing microfibers in the welded seam material. Determination of formation mechanism of boride microfibers, originated in the welded seam material, will become the basis for optimizing of fusion welding modes, in particular, electron beam welding mode. The purpose of this study is the determination of formation mechanism of boride microfibers originated in the welded seam material. Two most probable variants of the formation mechanism are analyzed, which involve eutectic decomposition during crystallization from a liquid melt or eutectoid decomposition from a metastable crystallized alloy. The third version is a mixed variant of the two above-mentioned mechanisms. In the article the results of metallographic analysis of features of boride phase distribution and an analysis of elemental composition of boride fibers based on local Auger electron spectroscopy are presented. The object of study was a Ti-TiB alloy joint obtained by electron-beam welding. The analysis factors were the features of size, orientation, and nature of the distribution of boride phase microfibers in different areas of the welded seam. The characteristic elemental composition of boride microfibers, which characterizes the correspondence to equilibrium phases, is also studied. The degree of deviation of the ratio of boron and titanium in such a phase from the thermodynamically equilibrium in different layers of the material of the welded seam, formed by an electron beam in vacuum, is determined. The dependence of boride phase distribution under various conditions of heat exchange in the welded seam material on the side surfaces and in the central regions is established. It is shown that some of boride microfibers formed in the material of the welded seam are characterized by a deviation from the thermodynamically stable composition ТіВn (n = 1) to ТіВn (n = 0.85). The dendritic nature of boride microfibers distribution and the presence of meta-stable phase formations on Ti and B basis provide the grounds for proposing the predominant mechanism for the formation of structure of the welded seam material in the Ti-TiB alloy during crystallization. An analysis of hypothetical variants of the formation mechanism of boride microfibers originated in the welded seam material showed that the formation of a dendritic type of structure is characteristic for the growth of crystals of a new phase in the liquid phase. Such growth is characterized by the formation of equilibrium phases. The presence of a significant amount of non-equilibrium boride phase in the welded seam indicates the residue of non-equilibrium boron in the titanium matrix and continuation of growing of boride fibers in the crystallized welded seam. A determined mechanism for formation of boride microfibers originated in the welded seam material is eutectic decomposition during crystallization from a liquid melt with the formation of TiB microfibers and further growth of such crystals due to eutectoid decomposition from a metastable crystallized Ti-TiB alloy. The results obtained make it possible to understand the mechanism of formation of a welded seam in welded natural-composite metal materials, which permits to develop the recommendations for optimizing the welding technology for such materials.

Potential of additive manufacturing technologies, namely, xBeam 3D Metal Printing for the fabrication of uniform Ti–6Al–4V (Ti-6-4, mas.%) material as well as layered titanium-based structures, with mechanical properties sufficient for wide practical application is demonstrated. The key distinctive features of this process are titanium alloy wire as a feedstock material and hollow conical electron beam for heating and melting of the wire. 3D printed with special ‘shift strategy’ Ti-6-4 alloy meets requirements to mechanical characteristics of corresponding conventional cast and wrought products, if microstructure features, material anisotropy and crystallographic texture are controlled with proper selection of processing parameters. Production of multilayered materials consisting of combined layers of different titanium materials, viz. commercially pure titanium (CP-Ti), Ti-6-4 and high-strength T110 alloys, as well as metal matrix composites (MMC) based on Ti-6-4 matrix reinforced by fine TiC particles is considered. Microstructural features and mechanical properties of all 3D printed materials are investigated. Terminal ballistic tests are performed with different ammunition. Described results show the promising potential of 3D printing technologies, xBeam 3D Metal Printing as an example, for manufacturing of titanium-based multilayered armour materials with reduced thickness and weight, and at the same time, sufficient protection characteristics.

Finding the right coatings for cutting tools is essential in order to increase the tool wear resistance and, thus, to get better surface roughness for the machined workpieces, and to improve productivity. A coating requirements are not only its mechanical and strength properties, but also its response to a given load and a given wear exposure. To expand ideas about the phenomena and mechanisms of wear of tungsten-based vacuum-arc coatings on the cemented carbides-based cutting tools during mechanical processing of titanium alloy Ti--6Al--4V, vacuum-arc W--N, W--Zr--N, W--Nb--N, W--Cr--N, W--Mo--N, W--TiSi--N, W--TiAlYCr--N coatings are obtained, investigated and tested on the CNC turning machine SMT 500 Swedturn with use of 8%-oil--water emulsion under pressure of 10 bars. Several main wear mechanisms and their influence on the geometry of vacuum-arc coatings are established, and factors influencing on the improvement of the operational properties of the tool are investigated. [ABSTRACT FROM AUTHOR]

Results of detailed investigations by the method of transmission electron microscopy are presented, and evaluation was performed in the system of chemical composition→structure→properties of welded joints produced by electron beam welding of experimental high-temperature multicomponent titanium alloys doped by niobium and silicon. It was found that in order to eliminate the gradient by strength and fracture toughness, it is necessary to ensure formation of a homogeneous dispersed platelike structure at uniform distribution of the density of dislocations and phase precipitate particles. Such a structure will ensure a high level of mechanical properties and crack resistance of metal in titanium alloy welded joints. 20 Ref., 2 Tabl., 6 Fig. [ABSTRACT FROM AUTHOR]

In order to implement the electron beam melting technologies the E.O. Paton Electric Welding Institute of NASU developed a multifunctional electron beam unit UE-5810 of megawatt class, designed for producing ingots of titanium and its alloys of up to 20 tons weight. Description of a multi-purpose universal electron beam unit UE-5810 and its specification are given. Functional features of the components of the unit, technological fixtures and electron gun are described. Electron beam unit UE-5810 is a reliable highly efficient installation of industrial type for melting highly reactive metals and alloys, as well as treatment of the produced ingots by surface melting. 12 Ref., 8 Fig. [ABSTRACT FROM AUTHOR]

Applying the method of HVOF-spraying with the use of mechanically-alloyed powders based on the amorphized FeMoNiCrB alloy with the additions of (Ti, Cr)C and FeTiO3 compounds, the coatings with amorphous crystalline heterophase structure were produced. The coatings of FeMoNiCrB‒(Ti, Cr)C and FeMoNiCrB‒FeTiO3 systems have a dense fi ne-grained structure with a porosity of 2.4 and 1.2 % and a hardness of 5510 ± 250 and 4410 ± 190 MPa, respectively. The study of corrosion resistance and resistance to fretting corrosion of the developed coatings was conducted. It is shown that the use of composite powders based on FeMoNiCrB alloy with the addition of (Ti, Cr)C and FeTiO3 compounds as spraying materials allows increasing the protective properties of the coatings compared to the coating of FeMoNiCrB alloy. It was found, that in the case of producing composite FeMoNiCrB‒(Ti, Cr)C and FeMoNiCrB‒FeTiO3 coatings on the steel base St3, the corrosion resistance of the specimens in the solutions of 3% NаСl, 10% Н2SО4 and 10% КОН is increased by 7.3, 9; 3.9, 5.3 and 9.5, 9.7 times, respectively. FeMoNiCrB‒(Ti, Cr)C and FeMoNiCrB‒FeTiO3 coatings have a fairly high resistance to fretting corrosion, which is 4.6 and 5.8 times higher than the resistance of titanium ОТ4-1 alloy. The obtained results indicate the prospect of using HVOF-spraying of the developed FeMoNiCrB-(Ti, Cr)C and FeMoNiCrB-FeTiO3 coatings to strengthen and restore surfaces operating in aggressive environments and those subjected to fretting corrosion. 26 Ref., 6 Tabl., 4 Fig. [ABSTRACT FROM AUTHOR]

The established regularities of the processes of alloying element evaporation and crystallization at electron beam melting were the base for determination of the melting modes and optimization of the technology of producing defect-free and chemically homogeneous ingots of a promising Ti–6Al–7Nb titanium alloy for medical purposes, having a homogeneous fine-grained structure without any traces of zonal segregation. Microstructural studies showed that Ti‒6Al‒7Nb alloy is a two-phase α+β titanium alloy of martensitic type, in which 1…2 mm thick precipitates of α-phase are observed on the boundaries of primary β-grains, and in the grain body formation of a platelike (widmanstaetten) morphology of α- and β-phase precipitates is found, the length of which inside the grains is equal to 10…40 μm. Such a structure ensures the best combination of the alloy mechanical characteristics, namely high values of strength (905 MPa) and ductility (13.5 %), which meet the requirements of international standards for titanium alloys for medical purposes. 20 Ref., 3 Tables, 12 Figures. [ABSTRACT FROM AUTHOR]

Statistical data of many national registers and medical societies show that aseptic instability of the hip joint prosthesis is one of the main obstacles in the path to application of orthopedic implants. One of the causes for aseptic instability is manifestation of stress shielding effect, which is due to mismatch of the moduli of elasticity of the implant and bone tissue. Methods are considered, which allow lowering the modulus of elasticity of the metal implant, bringing it closer to the respective modulus of elasticity of bone tissue. It is found that reaching the posed goal by replacement of the traditional metals, which are used for implant manufacture, by alloys with much lower modulus of elasticity, is a task, which has not been solved technologically in their mass production. The currently most common methods of lowering the modulus of elasticity of orthopedic implants were analyzed, and their advantages and short-comings are indicated. The most serious problem in mass application of advanced additive technologies in implant manufacture is their labour- and material consumption. It is found that application of surface modification technologies, in particular plasma methods of porous coating deposition is the most affordable and effective method of lowering the modulus of elasticity of the implant surface, contacting the bone, with a high probability of reduction of the stress shielding effect manifestation. 53 Ref., 8 Fig. [ABSTRACT FROM AUTHOR]

Proceeding from the results of the performed package of research work, it was established that the chemical composition of metal in the surface-melted layer of high-temperature titanium alloy VT9 corresponds to standard requirements; and a lowering of aluminium content, an alloying element with vapour pressure higher, and an increase in the content of molybdenum and zirconium, alloying elements with vapour pressure lower than that of titanium, is observed. Investigations of the surface-melted layer showed that the depth of penetration of the surface layer in ingots of high-temperature titanium alloy VT9 of 600 mm diameter reaches 8 mm, the ingot surface is high-quality mirror-like with characteristic vacuum etching, even microrelief without cracks, tears or lacks-of-fusion, its roughness is in the range of 3…4 class at waviness of 0.2…0.6 mm. The surface-melted layer of the ingot has a finer structure, compared to base metal, and it consists of areas with isolated α-plates of 1.0…2.5 μm thickness, where the α-plates are gathered into colonies of 10…50 μm width, and the gaps between them are taken up by dispersed particles of 1…2 μm size, which can be the products of metastable phase decomposition. Ref. 13, Tabl. 1, Fig. 10. [ABSTRACT FROM AUTHOR]

The corrosion strength of plasma coatings made of composite powders based on FeAl intermetallic in different corrosive environments was investigated. For deposition of coatings, powders based on FeAl intermetallic were used, which was produced by mechanochemical synthesis with the introduction of additional alloying elements of titanium and magnesium into their composition. Electrochemical tests of plasma coatings were performed by a potentiostatic method in a 3% NaCl solution and in a 10% H2SO4 solution. It was revealed that the rate of the corrosion process of plasma coatings of FeAl system depends on the nature of electrolyte and the mechanism of electrochemical process. Electrochemical studies of plasma coatings of FeAl system showed that corrosion strength in a 3% NaCl solution is by an order higher than in a 10 % H2SO4 solution. It was found that introduction of alloying element of titanium to the composite coating based on FeAl intermetallic results in a 2-5 times increase in corrosion strength of coatings in a 10 % H2SO4 solution. It was shown that plasma coatings based on FeAl intermetallic on a scale of corrosion strength in a 3% NaCl solution are in the “resistant” group. The electrochemical studies showed the ability of these protective coatings to operate in salty neutral solutions. 18 Ref., 3 Tabl., 2 Fig. [ABSTRACT FROM AUTHOR]

Paper examines the effects of ultrasonic impact treatment on the surface hardening of the Ti--6Al--4V (ВТ6) alloy samples obtained by the standard technology and printed by the additive technology 'xBeam 3D Metal Printing'. To determine the optimal level of the load on the indenter for the micro- hardness measurements this level is estimated by changing the load in the range of 25--200 g. Orientation dependences of the microhardness of the 3D- printed Ti--6Al--4V (ВТ6) alloy have a slight spread of values (± 0,2 GPa). The changes in microhardness of both types of samples are investigated and analysed depending on the duration of ultrasonic impact treatment in the argon stream. The increase in the ultrasonic impact treatment induced hardening effect of the 3D-Ti--6Al--4V (ВТ6) sample as compared to the annealed Ti--6Al--4V (ВТ6) sample can be explained by the change in the structural state, compressive residual stresses, as well as strain induced mechano-chemical oxidation of the surface. The difference in the strength, hardness and plasticity of the near-surface layers leads to a change in mechanical behaviour, which gives the potential for further improvement of the protective characteristics. Hardness measurements can be used to predict the strength of 3D-Ti--6Al--4V (ВТ6) depending on the type of additive manufacturing technology and on the usually required subsequent mechanical or heat treatment. [ABSTRACT FROM AUTHOR]

The advantages of using the technology of A-TIG welding (TIG welding along the layer of activating flux – activator) of structurally complex elements of titanium alloys, including butt and spot overlapped joints of various thicknesses, as well as joints with variable heat dissipation, are shown. The relationship between the geometry of welds, structure and properties of welded joints produced by TIG and A-TIG welding methods was studied. A-TIG welding technology was tested in industrial conditions during creation and repair of problematic units of aircraft and convertible gas turbine engines. The A-TIG welding method is recommended for industrial implementation when creating welding structures from titanium alloys of a complex geometry. 15 Ref., 7 Tabl., 12 Fig. [ABSTRACT FROM AUTHOR]

The structure and mechanical properties of high-temperature titanium alloy of Ti–Al–Zr–Si–Mo–Nb–Sn system after hot deformation treatment by various modes were studied. It was found that metal deformation treatment performed in the upper part of the region of (α+β)-phase existence, ensures an increase of material ductility by almost 30 times, compared with lithium, and high strength values, both at room and at working temperature of 600 °С. [ABSTRACT FROM AUTHOR]

Additive manufacturing, in particular, selective laser melting (SLM) is a modern method of manufacturing parts and units of a complex geometry from metal powder, which are difficult or impossible to be reproduced in the conditions of traditional manufacturing. This technology is featured by residual stresses generated at the stage of manufacturing parts. Since titanium alloys are characterized by low thermal conductivity, the problem of forming residual stresses is of particular relevance for them and heat treatment for their removal is mandatory for products manufactured using SLM technology. Since the structural state of products manufactured by SLM technology differs from that formed with the use of traditional technologies, it is necessary to study the effect of annealing for residual stresses removal on mechanical properties and microstructure of Ti6Al4V alloy manufactured by SLM technology. The specimens were studied after annealing with an exposure time of 1. . .5 h at 800 °C. It was found that as compared to the initial state after manufacturing, ultimate strength after heat treatment for 1. . .5 h undergoes a decrease by 20.55...–23.03 %, relative elongation has an increase by 31.33. . .35.57 %. At the same time, the nature of variation in the values of relative reduction in area is non-uniform: annealing with an exposure of 1 h does not cause significant changes; with an increase in the exposure time to 2, 3, and 4 h, a decrease in this characteristics is observed, respectively, by 9.03; 45.97 and 62.56 % as compared to the initial state; after exposure for 5 h, the value of the relative reduction in area undergoes an increase in this characteristics as compared to the values after exposure for 4 h – by ~26.12 %. According to the results of the correlation analysis of the values of mechanical properties and microstructure parameters, it was found that the shape factor of α-phase plates has a high correlation with the values of ultimate strength, and the amount of α-phase is most correlated with the values of relative reduction in area during static tension. 7 Ref., 2 Tabl., 11 Fig. [ABSTRACT FROM AUTHOR]

The influence of filler material on the properties and structure of joints of VT19 titanium pseudo-β-alloy, produced by tungsten electrode argon-arc welding was studied. It was established that predominantly β-phase in the amount of 60…77 % was present in the weld metal of all the joints of VT19 pseudo-β-alloy. Joints of VT19 alloy produced by argon-arc welding, using VT1-00sv filler wire in the amount of 20 %, have the tensile strength values at the level of 965 MPa, and exceed the base metal strength. To produce a homogeneous structure of the joints, it is necessary to use postweld annealing. The impact of annealing at the temperature of 760 °C results in formation in the metal of the joints produced by argon-arc welding of VT19 alloy, of a uniform, homogeneous, fi ne two-phase (α+β)-structure with values of tensile strength of welded joints on the level of 980 MPa. [ABSTRACT FROM AUTHOR]

A mathematical model of the process of dissolution of oxygen-containing inclusions of titanium in titanium alloy melt was constructed, which allows calculation of the dependence of particle dissolution rate on melt temperature. The dynamics of oxygen distribution in Į-titanium particles during the dissolution process was established. Time intervals of complete dissolution of oxygen-containing titanium inclusions of different chemical composition and initial dimensions were determined. [ABSTRACT FROM AUTHOR]

The main goal of this work is to determine the melting temperature range and phase composition of multicomponent Ni-based alloys by applying the methods of design of alloys (CALPNAD method) in combination with statistical processing of the results. In particular, the liquidus and solidus temperatures for a number of experimental alloys of the Ni–Cr–Co–Al–(Ме) system are calculated. The degree of influence of adhesive-active elements (Ti, Nb, Zr) on the liquidus temperature and phase composition of alloys of this system is established. The approximate content of alloying elements to ensure the required melting point of experimental filler metals is determined. As shown, alloying zirconium significantly reduces the solidus temperature thus significantly expanding the melting range of experimental alloys. This effect is associated with the formation of low-temperature zirconium eutectic. The influence of titanium and niobium on the amount and thermal stability of the γ′-phase in experimental alloys is studied. The influence of refractory components (Mo, W, Re) on the presence of topologically close-packed (TCP) phases is studied. As noted, partial replacement of tungsten by rhenium in experimental Ni–Cr–Co–Al–(Ме)-based alloys significantly reduces the amount of harmful µ- and p-phases. [ABSTRACT FROM AUTHOR]

Welding of titanium alloys, doped by silicon, requires application of additional technological operations, such as local heat treatment and preheating. In view of the fact that tungsten electrode argon-arc welding became widely applied in industry, the possibility of application of preheating for argon-arc welding of high-temperature pseudo-~ titanium alloy of Ti–5.6Al– 2.2Sn–3.5Zr–0.4Mo–1.0V–0.6Si system was studied. Joint preheating up to temperatures of 200 and 400 °C was used in the work. Temperature of preheating before welding in the range of 200…400 °С does not influence the final microstructure of the produced welded joints. AAW joints of high-temperature pseudo-~ Ti–5.6Al–2.2Sn–3.5Zr–0.4Mo–1.0V–0.6Si alloy, made with preheating up to 400 °С, have the highest ultimate tensile strength on the level of σt = 1160.1 MPa, impact toughness values of samples with a sharp notch are on the level of 8.3 J/cm2. [ABSTRACT FROM AUTHOR]

Experimental sparsely-alloyed Ti–2.8Al–5.1Mo–4.9Fe and Ti–1.5Fe–0.4O titanium alloys, produced by cold-hearth electron beam melting, were studied. Metallographic, structural, X-ray structural and transmission electron microscopy studies were conducted, thermokinetic diagrams of titanium alloy transformation were plotted, and critical cooling rates were determined, physical and computer modeling of phase transformations in the studied titanium alloys was performed. It was found that sparsely-alloyed Ti–2.8Al–5.1Mo–4.9Fe titanium alloy is a two-phase pseudo-β-alloy, and Ti–1.5Fe–0.4O alloy is a two-phase pseudo-α-alloy. It was established that in Ti–2.8Al–5.1Mo–4.9Fe alloy hardening occurs due to formation of dispersed particles of Mо9 Ti4 and Fe2 Ti titanium intermetallics, and in Ti–1.5Fe–0.4O alloy it is ensured by dispersion-strengthening particles of Ti3 O5, Ti4 Fe2O and FeTiO titanium oxides. Sparsely-alloyed Ti–2.8Al–5.1Mo–4.9Fe titanium alloy has higher strength values, compared to these values of Ti–1.5Fe–0.4O alloy, but lower ductility and impact toughness values. Critical cooling rate for the experimental Ti–2.8Al–5.1Mo–4.9Fe titanium alloy is equal to 20 °С/s. Ref. 32, Tabl. 4, Fig. 9. [ABSTRACT FROM AUTHOR]

The paper presents the results of investigations of the quality of electroslag welded joints of 100 mm plates from VT6 titanium alloy. Investigations included X-ray inspection, chemical and gas analysis, optical metallography, mechanical tensile and impact toughness tests, as well as fractographic analysis. X-ray inspection and optical metallography of the welded joint showed absence of surface and inner defects in the weld metal and HAZ. Gas analysis of the weld metal demonstrated its correspondence to standard requirements to VT6 alloy. Ultimate strength of weld metal was equal on average to 90 % of base metal strength, and impact toughness (KCU) was 1.6 times higher than in the base metal. Fractures of metal of the weld and HAZ were of transcrystalline nature of a mixed type, with areas of both ductile and brittle fracture. It is shown that the welded joint mechanical properties are determined, primarily, by the size of grains and microstructure of the weld and HAZ metal, forming under the conditions of a low cooling rate and high heat input, characteristic for electroslag welding process. Ref. 9, Tabl. 3, Fig. 8. [ABSTRACT FROM AUTHOR]

A mathematical model was developed of the processes of alloying element evaporation at cold-hearth electron beam melting of ingots of alloys based on titanium aluminide of Ti–Al–Nb–Cr–Mo alloying system that establishes the dependence of alloying element concentration in the ingot on technological parameters of melting and chemical composition of the initial charge. It is shown that the developed mathematical model adequately describes the real evaporation process at electron beam melting of titanium aluminide alloy. The regularities of alloying element evaporation at electron beam melting of alloys based on titanium aluminide of Ti–Al–Nb–Cr–Mo system were established, which allow predicting the chemical composition of the ingots and optimizing the technological parameters of melting. Ref. 21, Tabl. 2, Fig. 5. [ABSTRACT FROM AUTHOR]

A complex of research work was performed on the base of EBM technology to produce high-strength complex-alloyed titanium alloys of Ti‒Al‒Zr‒Si‒Mo‒Nb‒Sn system with silicon content, higher than the thermodynamically stable value in the solid solution. Alloys of this system are promising for creation of a new class of materials with a high level of heat-resistant characteristics. It is shown that EBM allows producing ingots of high-temperature titanium alloys of Ti‒Al‒Zr‒ Si‒Mo‒Nb‒Sn system, which are characterized by sufficient chemical homogeneity and absence of casting defects. It is found that tin presence lowers silicon solubility in the test alloys and intensifies silicide release. Here the structure is also refined. It is found that additional alloying elements influence silicon solubility in titanium, forming complex silicides of (Zr, Ti)5 Si (Ti, Zr)3 Si type in the test alloys. It is shown that the microstructure of the test cast alloys consists of platelike α-phase packets within primary β-grains, having different crystallographic orientation. Ref. 18, Fig. 8. [ABSTRACT FROM AUTHOR]

A comparative analysis of the structural-phase state, microhardness, wear resistance and wear mechanisms is carried out during tests on fixed abrasive and non-rigid fixed abrasive particles, as well as in sliding friction conditions, arc-deposited coatings with a composite material (CM) based on the powder material of the Ni–Cr–B–Si system, modified with a material containing titanium and chromium borides and obtained using the selfpropagating high temperature synthesis. It is found that under wear conditions for fixed abrasive particles, the wear resistance of CM (10% modifying composite material (MCM) + 90% ПГ-10Н-01) is 1.5 times higher, and CM (20% microns + 80% ПГ-10Н-01) is 1.7 times higher than that of the ПГ- 10Н-01 alloy. This is due to the introduction of MCM, which contributes to the formation of new crystallization centres during surfacing and as a result leads to grinding of the structure. The ПГ-10Н-01 nickel-based plastic matrix redistributes stresses, providing conditions in which solid components occupy a favourable position. This eliminates the local increase in contact pressure and reduces the probability of separation of solid wear-resistant particles. It is found that under friction under the influence of non-rigid abrasive particles, the increased wear resistance (1.2 times at a content of 10% MCM and 1.4 times at 20% MCM more compared to the ПГ-10Н-01 alloy) is due to the higher ability of CM to resist micro-cutting processes due to the formation of a structure based on a nickel matrix, which contains evenly distributed solid inclusions in the form of titanium diboride (TiB2), nickel borides (Ni3B) and chromium (CrB), titanium (TiO) and iron (Fe3O4) oxides. Based on the obtained experimental results, it is concluded that the presence of titanium diboride (TiB2), chromium borides (CrB) and nickel (Ni3B), titanium oxides (TiO) and iron (Fe3O4) in the deposited coating leads to a decrease in the intensity of wear under various friction conditions. [ABSTRACT FROM AUTHOR]

Eight alloys of the Ti–Nb–Mo system are synthesized by the arc remelting method. As shown, they have dendritic microstructures typical of casting. The phase composition and lattice periods of the formed phases are determined. Using the method of differential thermal analysis (DTA), phase transformations in the solid state are investigated, and the temperatures of the onset of melting and crystallization are determined. For alloys, the solidus temperature of which is above 2000°C, together with DTA, the Pirani– Althermum pyrometric method is also used. Based on the experimental data, the temperature dependences of the hardness of the alloys are constructed and the activation energies of deformation of the material under the indenter are calculated. The analysis of the curves of the dependence of the hardness of the alloys is carried out and the temperature of the sharp softening of the material is determined. As shown, that the α → β transition in titanium alloys with an unstable β-phase does not lead to a significant change in hardness. [ABSTRACT FROM AUTHOR]

Titanium alloys are the main structural material of aerospace system component, about 75 % of titanium and titanium alloys are used in the aerospace industry, which have the advantages of low density, high specific strength and excellent corrosion resistance, However, its low wear resistance limits the further application of titanium alloy. Therefore, it is of great significance to the surface protection of titanium alloy. Surface coating technology can solve the problems of titanium alloy wear. Currently, there are many coating technologies to solve the problems of wear and corrosion, including the cold spraying(CS), high velocity oxy-fuel(HVOF), the thermo-chemical treatment, the gas phase deposition, the laser melted; the plasma spray coating, the double-plasma surface alloying technology, arc spray, etc, However, when thermal spraying is used to prepare anti-titanium fire coating, the tip of the blade is prone to overheating, thus affecting the performance of the blade. But cold spraying technology is due to the preparation of titanium alloy protective coating in solid state, and the coating has high bonding strength and good impact toughness, furthermore, it can deposit almost any powder materials, such as pure metals, including aluminum(Al), magnesium(Mg), titanium(Ti), nickel(Ni), cobalt(Co)，niobium(Nb), tantalum(Ta), Copper(Cu), tungsten(W), etc; nonmetal such as ceramic, etc; Metallic alloys; composite coating, including Al-Zn, Ti-Al, Ni-Al, Al-Mg, Al-SiC, Al-Al2O3, Ti-Ti6Al4V-Al2O3, Ni-Zn, Ni-cBN, Ni-Zn-Al2O3, Ti-Ta, Al-Mg17Al12, Al-FeSiBNbCu, WC-Co, Cr3C2-NiCr, etc. It can also directly sprayed mixed powder to produce wear resistant coatings, hence, it is widely used. At present, cold-sprayed titanium alloy materials are mainly used in the field of substrate protection and repair, and the field of cold-sprayed titanium alloy additive manufacturing that has appeared in recent years is still in the stage of process and basic theoretical exploration. In order to better understand the latest status of cold spray coating of titanium alloy, in this paper, the wear resistance coating on aircraft titanium alloy parts by cold spraying technology was reviewed, produce wear resistance coating directly by cold spraying technology was analyzed.

The results of studies of porosity, microhardness, microstructure, phase composition, and distribution of alloying elements in samples of VT6 and VT8 titanium alloys are presented. They were synthesized from a mixture of powder components with various modes and subjected to severe plastic deformation by torsion under high pressure with multiple regimes. The effects of sintering time and the regimes of subsequent severe plastic deformation on the microhardness, and it is dispersion through the cross-section of the samples were identified. It was shown that, regardless of the sintering regimes, the microhardness of the samples across the cross-section and does not depend on the processing regimes. Consequently, this serves as an indication of a saturation effect of fragmentation and hardening. The analysis of the porosity of the initial samples concerning both the sintering time and the samples subjected to high pressure torsion was conducted. It was demonstrated that irrespective of the initial value of porosity, severe plastic deformation enables the complete elimination of porosity across the entire cross-section of the samples. It was concluded that the formation of new phases does not occur in the samples of the studied titanium alloys during the process of the severe plastic deformation. It was shown that the samples after sintering obtain a significant chemical heterogeneity, which is effectively eliminated in the process of deformation. The beneficial role of the generated in the samples vortex flows, which facilitate efficient mass transfer was confirmed after adding slowly diffusing chemical elements into the composition of the powder mixture. Considering the physical similarity of the processes which occur in a thin deformable layer of samples during the severe plastic deformation by twist extrusion and high pressure torsion, conclusions on the effectiveness of using twist extrusion to homogenize structural and chemical inhomogeneities in bulk billets of the sintered titanium alloys were drawn.

Titanium alloys have the advantages of high specific strength, good corrosion resistance, high heat resistance, and low density, which is the main structural material of aerospace system components, including compressor blade, cartridge receiver, blisk, engine nacelle, thermal baffle and so on. At present, about three-quarters of titanium and titanium alloys in the world are used in the aerospace industry, including A350 for 14%, F18 for 15 %, B787 for 15 %, SU-57 for 18 %, J-20 for 20 %, FC-31 fighters for 25 %, F35 for about 27 %, and F22 up to 41 %, etc, so it has the reputation of "space metal". However, its low wear resistance limits the further development of titanium alloy. Besides, its high manufacturing cost, if only require the occasion of surface performance can reduce the use of the substrate, and then reduced the cost. Therefore, the study of aircraft titanium alloy is of great significance, the protection of titanium alloy includes alloying technology and coating technology. Alloying technology mainly adds other elements on its basis to improve the performance, while the most popular method is coating technology, the present, there are many coating technologies, include high-velocity oxy-fuel (HVOF), HVAF, cold spraying, laser cladding, laser micro-fusion in-situ synthesized technology, micro-arc oxidation, laser melt injection (LMI), supersonic laser deposition (SLD) and supersonic plasma spray technology, surface repair titanium alloy parts by cold spraying technology are good ways to solve those problems. Because of its low process temperature, no oxidation, only plastic deformation, and repair efficiency are high, the protective coating has high bonding strength and good impact toughness. In this paper, the types and applications of aircraft titanium alloys were reviewed, the latest research results of surface repair of titanium alloys parts by cold spraying technology were reviewed, technological parameters of the cold gas dynamic spraying technology was analyzed, including powder size of particles, morphologies, critical velocity, particle compression rate, substrate preheating effects on the particle/substrate adhesion, etc.

The properties of electron beam welded joints of sparsely-alloyed titanium pseudo-β-alloy of LCB type of Ti–2.8Al– 5.1Mo–4.9Fe alloying system and structural VT19 pseudo-β-alloy of Ti–3Al–5.5Mo–3.5V–5.5Cr–1Zr alloying system were studied. It was found that the joint structure consists of β-phase grains, in which dispersed precipitates of α-phase are present. The quantity of β-phase in the weld metal after electron beam welding is recorded on the level of 71….74 % in Ti–2.8Al–5.1Mo–4.9Fe alloy and of 74….87 % in Ti–3Al–5.5Mo–3.5V–5.5Cr–1Zr alloy. Local heat treatment of welded joints does not ensure lowering of β-phase content in the metal of the weld and HAZ, but allows producing almost full strength joints, with strength level of 98 % of that of the base metal in as-rolled condition. Hardening followed by aging for joints of Ti–2.8Al–5.1Mo–4.9Fe alloy is the most effective heat treatment, which allows increasing the joint strength up to 1204 MPa at impact toughness values on the level of 3.7...4.2 J/cm2 . Ref. 14, Tabl. 4, Fig. 5. [ABSTRACT FROM AUTHOR]

Possibilities are considered of processing titanium and titanium wastes under the conditions of plasma-arc remelting into a through crucible in the form of sublimates, which formed in electron beam furnaces and gate systems from VT5 type alloy, produced in vacuum induction furnaces. Possibilities of plasma-arc skull melting at processing these wastes into small ingots and 70 % ferrotitanium were studied. Hydrogen behaviour in furnace atmosphere at remelting of the above-mentioned wastes was investigated. It is shown that under the conditions of plasma-arc remelting it is possible to process titanium and titanium alloy wastes into billets for further remelting, castings and ferrotitanium. Ref. 9, Tabl. 3, Fig. 7. [ABSTRACT FROM AUTHOR]

The paper presents the results of modelling of temperature fields, stresses, and strains during additive multi-layer construction formation from the aluminium alloy 1561, low-alloyed structural steel 09G2S, and titanium alloy Grade 2. Based on the experimental results, which obtained earlier in E. O. Paton Electric Welding Institute of the N.A.S. of Ukraine about additive surfacing of these materials, a computer modelling to improve the technology of the additive process is carried out. In the course of the calculations, the influence of the algorithm of the sequence of deposition of additive layers--the surfacing of a cylindrical shell along a ring or spiral--is analysed on the temperature distribution in the cladding and its resistance to external loads. As established, during the formation of cylindrical shells by the additive method, it is advisable to use the technology of surfacing along a spiral and to use less thermally conductive structural materials--structural steels and titanium alloys. [ABSTRACT FROM AUTHOR]

The paper presents the technological characteristics of multicomponent nickel brazing alloys with a reduced amount of zirconium, which does not exceed 2% wt. Their temperature range of melting and wetting of heat-resistant nickel alloy ZhS6U are investigated. On the basis of the experimental data and using the methods of statistical analysis, a surface described a dependence of the spreading area of the experimental brazing alloys of the Ni-Cr-Co-W-Mo-Al-(Nb, Ti, Zr) system on the content of zirconium, titanium and niobium is constructed. In the process of analyzing the experimental data, the positive influence of niobium and titanium on the spreading of multicomponent brazing filler metal over substrates of the heat-resistant cast nickel alloy ZhS6U is established. As shown, in alloys with an increased amount of titanium the alloying with zirconium up to 1% wt. leads to a decrease in the spreading area by 15%. With a subsequent increase in the content of zirconium to 2%, the spreading area practically does not change. In alloys with a low titanium concentration, but with increased niobium content, alloying with zirconium in an amount of 2% wt. promotes a stable increase in the spreading area (up to 35%) and ensures the formation of a contact wetting angle within 10-11°. This is due to the presence in these brazing filler metal of a low-melting eutectic enriched with zirconium with a solidus temperature at level 1101-1103°C, which is confirmed by the results of hightemperature differential thermal analysis and micro-X-ray spectral studies. [ABSTRACT FROM AUTHOR]

Structural sparsely-doped titanium alloys are developed with the purpose of lowering the finished product cost. Possibility of application of tungsten electrode argon-arc welding (AAW) for sparsely-doped pseudo-β-titanium alloy Ti–2.8Al–5.1Mo–4.9Fe was evaluated. Influence of different kinds of argon-arc welding on weld formation and mechanical properties of Ti–2,8Al–5,1Mo–4,9Fe alloy joints were assessed. The effect of complete penetration AAW, semi-submerged AAW AAW with feeding unalloyed titanium welding filler wire VT1-00sv was studied. It was found that the structure of metal of the weld and HAZ in welded joints of sparsely-doped titanium alloy Ti–2.8Al–5.1Mo–4.9Fe made by AAW consists mainly of β-phase with precipitates of metastable α-phase. Lowering of AAW heat input for Ti–2.8Al–5.1Mo–4.9Fe alloy has a positive impact on the joint strength. So, among the welded joints made without changing the weld metal composition, the joints made by semi-submerged arc welding have the highest strength of 972 MPa and the highest impact toughness on the level of 5.7 J/cm2 . 15 Ref., 3 Tabl., 3 Fig. [ABSTRACT FROM AUTHOR]

The work is aimed at studying the effect of doping with tin in an amount of x = 1-8% wt. on the mechanical behaviour under uniaxial tension of alloys of ternary system Ti-12%Mo-xSn subjected to complex thermomechanical treatment, consisting of melting, homogenizing annealing, quenching, cold rolling with a compression degree of 90-99% and finishing quenching. The changes in mechanical properties of the ternary alloys depending on the concentration of alloying element are analysed. As experimentally established, an increase in strength indices with a decrease in ductility is noted with an increase in tin content up to 10%. Thus, the increase in yield stress is 20-40%, in ultimate strength is 27-35%, and in ductility is in the range of +10--30% as compared to the indices for the quenched binary alloy Ti-12%Mo after the similar thermomechanical treatment. Such deformation behaviour and an increase in strength characteristics are due to solid-solution hardening, while the alloy deformation occurs by mechanical twinning and phase transformation, that is confirmed by microscopic and X-ray diffraction studies. High ductility of alloys with tin concentration of 1-6% is due to the simultaneous induction of strain martensite with an orthorhombic lattice and twinning, which is accompanied by a high rate of strain hardening. [ABSTRACT FROM AUTHOR]

Corrosion characteristics of commercially pure Ti and Ti-6Al-4V alloy manufactured with press-and-sinter powder metallurgy are studied in HCl and H2SO4 water solutions with acid concentrations up to 80%. Changing of powder metallurgy processing parameters (powder size, compaction and vacuum sintering regimes) results in a number of structural conditions of produced materials with different residual porosity (1 to 5%) and grain sizes. As shown, the residual porosity of sintered titanium alloys is a key microstructure factor affecting corrosion resistance. Increase in total porosity and pore sizes leads to higher corrosion rate, while decreased porosity (1-2%) and minimized pore size is useful for improvement of corrosion characteristics. Optimization of material microstructure provides corrosion resistance of produced titanium-based materials sufficient for practice application in aggressive environments at chemical industries. [ABSTRACT FROM AUTHOR]

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper presents practical results of developments and investigations in the field of brazing various materials: aluminium, copper, high-temperature nickel and titanium alloys, as well as promising materials based on Ni3Al and TiAl intermetallics, and steels of different grades. Data on reactive-flux brazing of aluminium thin-walled structures in a controlled gas environment are given. A lot of attention is paid to producing brazed joints from dissimilar materials: Mo+C (stainless steel), W+Cu, hard alloy material (VK 20)+steel, Al+steel, etc. Effective application of the developed technologies of brazmg high-temperature nickel and titanium alloys in fabrication of critical structures for high temperature applications and results of mechanical testing of brazed joints are shown. The developed brazing filler metal and technologies of high-temperature vacuum brazmg were applied to produce joints from new generation alloys based on nickel and titanium aluminides, which have been successfully tested for long-term strength under the conditions of higher temperature and continuously applied stresses. [ABSTRACT FROM AUTHOR]

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electrometallurgy Today / Sovremennaya Elektrometallurgiya is the property of International Association Welding (Paton Publishing House) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electrometallurgy Today / Sovremennaya Elektrometallurgiya is the property of International Association Welding (Paton Publishing House) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)