VT6 Titanium Alloy Research Articles

Модификация поверхности карбидовольфрамового композиционного материала методами электронно-ионно-плазменного воздействия

The surface of a porous tungsten carbide pseudoalloy of the WC-WCoNiFe system has been modified by a pulsed electron beam and the method of combined electron-ion-plasma, which includes vacuum arc deposition of a film from VT1-0 titanium alloy (1 μm) and subsequent pulsed electron-beam processing of the"coating/substrate" system. Optimal modes of pulsed electron-beam processing were found depending on the energy density in the pulse (40-65 J/cm2) and the pulse duration (150-200 µs). It is shown that electron-beam surface treatment of a material of this class under optimal conditions of electron-beam processing makes it possible to increase the microhardness of the surface layer by 15% relative to the initial material. Using the methods of X-ray phase analysis, it was revealed that the increase in microhardness is due to the formation of the W2C phase in the surface layer and a decrease in the amount of the binder (WCoNiFe). It is concluded that the combined electron-ion-plasma treatment of a porous tungsten carbide pseudoalloy of the WC-WCoNiFe system makes it possible to form a modified layer with a minimum number of pores and cracks on the surface.

Исследование структуры и коррозионной стойкости титановых сплавов, полученных методом электроимпульсного (искрового) плазменного спекания

The results of the structure and corrosion resistance researches of titanium alloys VT1-0, PT-3B and VT6 obtained by spark plasma sintering (SPS) are described. Microstructure, phase composition and microhardness have been investigated. It is shown that the alloy samples have a homogeneous high-density microstructure and high values of microhardness. The alloys samples showed high corrosion resistance in the electrochemical corrosion tests in acidic aqueous solution causing intergranular corrosion. The alloys also showed high resistance against hot salt corrosion. It has been suggested that the high hardness of the alloys as well as the differences in corrosion resistance of the central and lateral surfaces of the samples are due to the diffusion of carbon from the graphite mold into the sample surface.

Исследование защитных свойств покрытий, полученных методом микродугового оксидирования в щелочных растворах электролитов

The article presents the results of a study of the corrosion properties of oxide coatings compacted with polymers and without compaction. Oxide coatings were obtained on VT1-0 and VT5 titanium alloys under the influence of fast pulsed actions of the micro-arc oxidation (MAO) process. To form MAO coatings, a pulsed mode of the process was used with an anodic current pulse duration of 250 ± 25 μs; the cathodic current pulse duration of 5 ± 0.5 ms; pause between anodic and cathodic current pulses 250 ± 25 μs; repetition rate of anodic and cathodic pulses 50 ± 0.5 Hz. Alkaline solutions were used as electrolytes. Fluoroplastic and epoxy resin solutions were used to seal the oxide coatings. The obtained MAO coatings have 4.4 – 7.5 % porosity on the VT1-0 alloy and 5.4 – 12.1 % on the VT5 alloy. The average diameter of oxide coating pores varies from 0.1 to 0,5 µm. X-ray phase analysis showed titanium dioxide in anatase and rutile modification in the oxide coatings composition. Tests performed in a 24 % solution of sulfuric acid at 40 and 75°C showed that the coatings on the VT1-0 alloy, both oxide and oxide-polymer, are more corrosion resistant than similar coatings on the VT5 alloy. All types of coatings produced on VT1-0 alloy are corrosion-resistant at a test temperature of 40 °C. Consolidation of MAO coatings with polymeric materials improves corrosion properties.

Microstructure and Mechanical Properties of Titanium Alloy VT6 and VT20L Diffusion Joints

Microstructure and Mechanical Properties of Titanium Alloy VT6 and VT20L Diffusion Joints

Composition of surface layers of titanium VT6 alloy after implantation of tantalum ions

The paper presents the results of the investigation of the surface layer composition of titanium alloy VT6 obtained after ion implantation with tantalum ions. It is shown that tantalum ion implantation can lead to a significant reduction in surface roughness, as well as a beneficial effect on the corrosion properties of the titanium alloy.

Влияние состава электролита на процесс электролитно-плазменного полирования титановых сплавов

Electrolyte-plasma polishing (EPP), also known as electrolyte-plasma treatment (EPT) has become widespread in industry as an alternative to traditional chemical, electrochemical and mechanical methods of improving the surface quality of products made of metallic materials. EPP is an innovative technology used to obtain metal surfaces with low roughness and a high gloss. Electrolyte-plasma polishing is widely used in aerospace, biomedical, precision instrumentation and other. This work is devoted to the study of the effect of the electrolyte composition on achieving the effect of polishing titanium alloys during the implementation of the EPP process. The studies were carried out on the example of polishing a titanium alloy VT6 (Ti – 6 Al – 4 V) in a three-component aqueous electrolyte containing NaF, NH2OH·HCl and KCl. It was shown that, depending on the concentration ratio of NaF and NH2OH·HCl protolyte salts, either the formation of oxide films or their anodic dissolution in the presence of a ligand can be observed on the treated surface, with the production of a clean, non-anodized metal surface, accompanied by a decrease in roughness (polishing effect). It is established that the polishing effect is achieved at a certain ratio of NaF and NH2OH·HCl, which ensures the formation of hydrogen fluoride in it in an amount sufficient to dissolve the oxide films formed on the treated surface.

ХАРАКТЕРИСТИКИ ПРОЧНОСТИ И ВЫНОСЛИВОСТИ ПРУТКОВ И ШТАМПОВОК ЛОПАТОК ИЗ СЕРИЙНЫХ ЖАРОПРОЧНЫХ ТИТАНОВЫХ СПЛАВОВ И НОВОГО ТИТАНОВОГО СПЛАВА ПСЕВДО-α-КЛАССА

Presents the microstructure and mechanical properties of bars and blade forgings made of new heat resistant titanium alloy. A typical microstructures of studied industrial alloys were demonstrated. The main clue of the article is noted to fatigue stability of bars and forgings material. The analysis of strength and impact toughness of bars and blade forgings made of industrial titanium alloys VT3-1, VT8, VT8M-1, VT9, VT20 were carried out in comparison with new heat-resistant titanium near- alloy.

ИЗНОСОСТОЙКИЕ ДЕТОНАЦИОННЫЕ ПОКРЫТИЯ НА ОСНОВЕ КАРБИДА ВОЛЬФРАМА ДЛЯ АВИАЦИОННОЙ ТЕХНИКИ

. The paper presents the results of a systematic study of detonation spraying of wear-resistant coatings from composites based on tungsten carbide used for hardening parts of aircraft vehicles. Using the LIH computer code the spraying modes were optimized and coatings from powders of domestic and foreign manufacturers were sprayed by the CCDS2000 plant. We measured the hardness, porosity, wear resistance and adhesion of obtained coatings and made a comparative characterization of residual stresses. The influence of spraying distance in the range from 50 to 400 mm and the angle of inclination of the treated surface up to 60 degrees on the quality of the coating was studied. Coatings with adhesion not less than 180 MPa and wear resistance characterized by specific wear less than 1.0 mm3/1000 rpm by ASTM G65 standard have been obtained which exceeds ten times the abrasion resistance of the VT20 titanium alloy.

Dynamic Strength of VT6 Titanium Alloy Manufactured by Laser Metal Deposition

Dynamic Strength of VT6 Titanium Alloy Manufactured by Laser Metal Deposition

Исследование стойкости пластин из сплава ВТ6 с линейно изменяющейся градиентной структурой к направленному высокоскоростному воздействию

The study results of the protective (barrier) properties of oxide and nitride coatings against the penetration of hydrogen during the thermal hydrogen treatment (THT) are summarized and the formation regularities of the linearly changing gradient structure of the VT6 titanium alloy are established. It has been found out that the finely dispersed (α + β) — structure on the surface formed as a result of THT provides increased strength properties, and the large-lamellar structure in the center provides high impact strength. It is shown that plates made of VT6 alloy of 12.5 mm thick with the linearly varying gradient structure demonstrate good dynamic resistance when fired with 5.45 mm and 7.62 mm jacketed bullets with a steel core.

Research of the structure and mechanical properties of microplasm porous coatings for biomedical purposes

The purpose of this work is to justify the feasibility of using the technology of microplasma sputtering from wire materials to obtain porous coatings for biomedical purposes, the modulus of elasticity of which is close to the corresponding characteristic of human cortical bone tissue. Analyzed the influence of the technological parameters of the microplasma sputtering regime on the degree of porosity of the coating. As a result, it was found that a decrease in current strength and consumption of plasma-forming gas, as well as a decrease in the speed of feeding the sprayed wire into the plasma jet lead to an increase in the porosity of the coatings. Even though these parameters are interrelated, for each individual material are limited by certain limit values, in case of nonobservance of which the stable process of melting and dispersion of the sprayed wire in the plasma jet becomes impossible. Established the limit parameters of the microplasma sputtering process for titanium alloy VT1-00 and zirconium alloy KTC-110, which allows obtaining a coating with maximum porosity. Conducted studies of the adhesion strength of the obtained coatings, formed through a low-porous sublayer, with the maximum degree of porosity according to the ASTM C633- 13 (2017) method which proven that the indicators of the adhesion strength of the coatings to the VT6 titanium alloy base at normal separation meet the requirements of the international quality standard ISO 13179- 1:2021.

Application of a universal system of epitesis fixation in the rehabilitation of patients with maxillofacial defects

The aim of the study was the creation of a universal epithesis fixation system that increases the reliability of its functioning in prosthetics of patients with maxillofacial defects of various genesis. After the surgical preparation of patients, in accordance with the indications of the underlying disease, epithesis was made from rigid silicone elastomers using CAD/CAM technologies. For the production of attachments, the VT1-0 titanium alloy common in medicine was used. A universal epithesis fixation system was used for prosthetics of various parts of the patient's face. Depending on the clinical situation and the size of the prosthetics area, an intermediate lattice plate (mesostructure) of the appropriate size and configuration was selected. Two types of attachments were used to fix epithets: magnetic with a counterpart and non-magnetic mushroom-shaped. The universal epithesis attachment system is distinguished by the possibility of using each hole of the lattice, both for attaching it to the bone structure and for installing attachments, which makes it easy to fix the lattice to residual bone fragments and center the position of the transition elements and attachments depending on the aesthetic and functional needs of the structure in whole. The success of prosthetics largely depends on the epithesis attachment system. The proposed universal epithesis fixation system allows its use in various clinical situations and also reduces the cost of prosthetics for patients with maxillofacial defects.

Горячий обжим крупногабаритных трубных заготовок

The generalized results of breaking-down modeling process of large-format pipe stocks made of titanium alloy VT6 are presented. Based on the simulation results of this operation, a static study has been undertaken, according to its results regression dependencies have been obtained, which contribute to assess the impact of a various parameter complex of this technology on the efficacy of the process.

Determining rational process parameters for selective laser melting of powder titanium alloy VT6

The current pace of development seen by the aerospace industry requires manufacturing techniques that would enable to make parts in the shortest possible timeframe and at minimum cost. Additive manufacturing technology, which is applied in blanking operations, should be described as an innovative area that ensures reduced labour intensity and manufacturing costs. Additive manufacturing technology allows to obtain blanks that are close to the geometry of the final part, i.e. near net shape parts. Additive technology makes it possible to produce unique hollow parts with sophisticated cooling channels of any shape, as well as mesh filter elements with the cell size determined by the size of the powder granules. Thus, printing of parts using metal powders would be of special interest for the aerospace industry. Selective laser melting (SLM) as one of the additive manufacturing areas is of relevance for the aerospace industry as it enables to obtain parts with a more sophisticated geometry in comparison with conventional technology. One of the key stages in the SLM process design that defines the mechanical properties of the synthesized material includes identifying rational parameters of scanning. This paper describes the results of a study that attempted to determine rational scanning parameters for powder titanium alloy VT6. Rational parameters of scanning were established through statistical processing of experimental data. Thus, they include the laser power of 275 W, the scanning pitch of 0.12 mm, the scanning speed of 805 mm/sec, with the layer thickness of 50 μm. The paper describes the results of a uniaxial tensile test carried out with cylindrical specimens produced at 0o, 45o and 90o to the dosing unit and at 0o, 45o, 60o, 90o to the base platform.The research work described in this paper was carried out by the staff of the Shared Knowledge Centre on its equipment using CAM technology; Agreement No. RFMEFI59314X0003.

Research of properties of AlB<sub>12</sub>-Al electric spark coatings on VT1-0 titanium alloy

Research of properties of AlB<sub>12</sub>-Al electric spark coatings on VT1-0 titanium alloy

TECHNOLOGY FOR RESTORATION AND REPAIR OF AIRCRAFT ENGINE PARTS

Problems of increasing the service life of compressor blades of aircraft gas turbine engines using detonation spraying technology are considered. The simulation of the parameters of the velocity and temperature of the particles of the sprayed material in the barrel of the detonation unit and in the flooded space to the substrate was carried out, followed by the choice of the optimal technological parameters of the spraying process. The control system of the detonation unit has been modernized. An experiment was carried out on the deposition of the Al2O3 coatings on the samples of a substrate made of titanium alloy VT3-1. Based on the results of the experiment, technological recommendations were developed concerning both the parameters of the spraying process and the parameters of the preparation of the substrate surface before spraying. The equipment for brazing the blades of the guide vanes is described and a device for spraying coatings on the end surfaces of the compressor blades is proposed. Thus, a complex technology has been developed for restoring the end surfaces of titanium alloy compressor blades by deposition of Al2O3 coatings.

Ускоренная оценка влияния технологических факторов на прочностные характеристики Ti-6Al-4V И Al-Cu-Mg

Introduction. The strength of construction materials when used under cyclic loads is of great importance in design engineering. A significant number of factors that affect the fatigue resistance have predetermined the creation of numerous methods that consider such influence. Nondestructive methods that are based on the connection of the physical degradation of material with strain properties enable evaluating experimentally the fatigue properties of materials. Purpose of study: the analysis of the processes of energy dissipation and strain accumulation during the inelastic cyclic strain of samples, using the VT6 (Ti-6Al-4V) titanium alloy and the D16 (Al-Cu-Mg) aluminum alloy before and after the technological impact. The work experimentally investigates the physical processes of degradation of the VT6 and D16 alloy samples that accompany the process of fatigue failure in materials with homogeneous and inhomogeneous stress-strain states in the concentrator (in the form of a hole and a weld). Typical modes are used to reach the fatigue testing that determine the critical stress in a material sample – the stress at which physical properties (temperature, strain) change without reaching the fatigue failure of samples. Critical stress amplitudes in the cycle, based on the data obtained during the experiment and the results of mathematical simulation, are compared. The effect of stress concentrators on critical loads that a detail can withstand after a unit operation is estimated by the finite-element method (FEM). As a result, the effect of the operational and technological factors on critical stress determined by strain and temperature is estimated. Comparative tests of the VT6 and D16 alloy samples with and without stress concentrators showed that the amplitudes of critical stress decrease by more than 30% in comparison with the ones that are without stress concentrators. The low-cycle fatigue tests of the D16 alloy samples are carried out. Mathematical simulation of the cyclic strain of the samples is carried out using MSC.Marc package. The results of the cyclic loading tests, which show that the characteristics of the technological process reduce the amplitudes of the critical stress of the VT6 and D16 alloys and affect the fatigue properties of the D16 aluminum alloy, are discussed. Mathematical simulation corresponded positively to the experimental data. Such correspondence indicates the possibility of conducting qualitative numerical assessments of the beginning of the inelastic strain accumulation process in structures with stress concentrators under the cyclic stress and the increasing stress amplitude, using the typical sample made of hardening elastoplastic material.

The influence of deformation conditions of titanium alloys on the surface quality of the feather of compressor blades

Purpose of work. Improving the quality of manufacturing of blanks of compressor blades from titanium alloys by precision stamping.
 Research methods and equipment. The research was carried out by precise stamping of blade blanks from the VT8 titanium alloy of the compressor of the D-436 aircraft engine at various temperatures of deformation.
 Precise stamping of parts was carried out in one tool stroke from a preliminary blank obtained by extrusion from a rod with a diameter of 30 mm.
 The research of the surface of the workpiece was carried out after processing by X-ray spectral analysis on a JSM6360LA scanning electron microscope.
 Microhardness was measured on a PMT-3 device at a load of 50 g.
 Investigations by precision stamping were also carried out on blades made of the OTCh-1 alloy of the input guide vane of the HPC of the D-136 helicopter engine and on the rotor blades of the compressor of the D-36 aircraft engine made of VT3-1 titanium alloy.
 The obtained results. It is shown that the conditions of deformation of a titanium alloy blade blank by precise stamping have a significant effect on the quality of its surface (macrostructure and microstructure). The deformation temperature of the metal affects the macrostructure and microstructure of the surface during precision stamping of blades from titanium alloys.
 Scientific novelty. It has been established that during precise stamping of blade blanks from titanium alloys, the deformation temperature has a significant effect on the quality of their surface. The values of the deformation temperature are determined, which provide a significant level of quality of the surface of the airfoil of the blades with precise stamping.
 Practical value. The results obtained made it possible to develop multi-pass stamping of blade blanks from titanium alloys, when fractional deformation in one pass is applied, not exceeding 30%.
 The heating temperature of the intermediate billet for deformation should be as close as possible to Тm within ± 10 °С.

Influence of the Sintering Conditions on the Structure, Phase Composition, and Porosity of Titanium Alloy VT6 Parts Formed by Powder–Polymer Injection Molding

Influence of the Sintering Conditions on the Structure, Phase Composition, and Porosity of Titanium Alloy VT6 Parts Formed by Powder–Polymer Injection Molding

Experience in the application of the non-destructive method of acoustic emission in the production of titanium billets and products of transport engineering

The article discusses the issue of using the non-destructive method of acoustic emission at the stage of blank production. So, due to the violation of the heat treatment modes, various defects are formed in the starting material, which affects the operational properties of the finished products. To eliminate this problem, the stages of production of titanium blanks and products of transport engineering were studied, such as: heat and mechanical treatment, ultrasonic quality control, determination of the level of mechanical properties and control of the structure. In the course of the research, a method of acoustic emission control was developed and tested. The experiment on setting the locations of defects was carried out on ingots of VT22 titanium alloy during cooling. The reliability of the developed method is confirmed by the existing method of ultrasonic flaw detection. It has been established that this method can be effectively used to control workpieces and machined workpieces for the manufacture of particularly critical mirrors for searching for inhomogeneous inclusions and increasing the efficiency of the technological process by eliminating machining of VT1-0 titanium surfaces with inhomogeneous inclusions. In addition, this method can be used to search for defects commensurate with the grain size of the ingot, as well as significantly smaller sizes.