Технологические процессы и материалы. Рубрика в журнале - Сибирский аэрокосмический журнал
Статья научная
The microstructure of a layered polymeric composite material used in the construction of a metal composite over- wrapped pressure vessel is investigated. The purpose of this work was to evaluate the parameters characterizing the structure of a laminate polymer composite material. Due to their technological and structural features, laminated polymer composite materials have a number of operational disadvantages that lead to a reduction in the overall level of strength characteristics. From the different zones of the nine-layer composite shell of the metal composite overwrapped pressure vessel, four vertical flat samples of the composite material for the manufacture of thin sections were cut out. The method of electron-scanning microscopy was used. The analysis of the percentage confinement of fibers in the ma- trix was carried out. The structure of the layered polymeric composite material is uniform with the presence of a dis- persion of distances between the fibers. The analysis of porosity in a composite material was carried out. The analysis of the structure of composite materials with different porosity has shown that with increasing pore area and their num- ber, the strength characteristics of composite tapes and reinforcing fibers decrease. Using the “mixture rule” and “polydispersity model”, the values of the effective modulus of elasticity of the composite material are estimated. It is determined that the modulus of elasticity of the composite material in the zone of the flange of the composite shell is less than at the equator. A complex evaluation of the quality of a laminate polymer composite material used in the structure of a metal composite overwrapped pressure vessel was carried out. The obtained results of inhomogeneity of the me- chanical properties of the composite shell are necessary for design calculation of the stress-stain state of metal over- wrapped pressure vessels.
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Approach to optimization of the magnetic circuit of a three-phase induction plant
Статья научная
The article describes an approach to optimization of the electromagnetic regimes of an induction metallurgical plant, designed to mix liquid aluminum under the influence of a running magnetic field. To improve the properties of the molten metal in the furnace, short pole linear magnetohydrodynamic machines with copper windings and a steel core are used. The open configuration of the magnetic circuit and the magnetic coupling between the windings of the inductor lead to asymmetry of the magnetic field. As a rule, a low-frequency transistor inverter is used in the power supply system of metallurgical machines intended to affect non-ferrous metals. Asymmetrical currents in the phases create specific modes of the frequency converter, close to emergency, and a two-phase, three-phase or multi-phase power supply system may become unbalanced. To calculate the integral magnetic fluxes in the toothed zone of an induction installation, it is convenient to apply a multiphase nonlinear model of a magnetic circuit. As a result of the iterative calculation, vector magnetic flux diagrams are obtained and the tractive forces in the melt are estimated. The best conditions for the impact on the melt are obtained with a given objective function when searching for options during optimization of the magnetizing forces of the windings.
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Balancing small engines-flywheels
Статья научная
When you create a small spacecraft there is the problem of redressing the imbalance of the rotor-flywheel of the small engine flywheel with the selection of weights, while the mechanical contact method leads to elastic deformation in the supports of rotation, which has a negative impact on their work especially at high speeds of rotation of the flywheel. From this perspective, there is a need to study other ways of balancing of rotors, flywheels, namely contactless bal- ancing of rotor of flywheels with the help of concentrated energy fluxes of laser and electron-beam evaporation of the metal. The technology of balancing with an electron beam has a number of advantages over the laser technology of bal- ancing for the realization of balancing of rotors of flywheels. For example, it is possible to implement the process of redressing of imbalance in the vacuum that brings the balancing conditions to real operating conditions. Also the reflectance of energy in the processing of electron beam is much lower than during laser processing, which demon- strates the efficiency of the process. The dependences of the intensity of evaporation from the settings of the laser and electron beam are defined. Contactless balancing of rotors of flywheels with the help of concentrated energy fluxes evaporation of metal is cur- rently possible, but it is necessary to have special equipment with the required capacity of operation.
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Computerized test stand for investigation of strain waves in composite constructions
Статья научная
The paper presents a test stand for investigation of ramp loading of composite constructions such as beams and plates. This ramp loading was performed using a striker with a piezoelectric force transducer. The velocity of the striker is up to 40 mps. The registration of the measurements results is carried out using a computerized measurement system. The experimental results of contact shock force acquisition are stated with appropriate calculations of nonstationary bending and shearing strain waves in glass-fiber-reinforced plastic beams and plates.
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Development of SEM method for analysis of organ-containing objects using inverse opals
Статья научная
The purpose of this study is to test the possibility of using inorganic macroporous structures of inverse opal in sample preparation for scanning electron microscopy of biological objects. As an absorbent substrate we used silica inverse opals prepared by a sol-gel method to study the biological objects. The process of manufacturing the inverse opal involves a complex multi-stage technological process. First, we synthesized submicron spherical particles from polymethylmethacrylate by the method of emulsifier-free emulsion polymerization of methylmethacrylate in an aqueous medium in the presence of a diazoinitiator. This method can be used to obtain an ensemble of particles with high monodispersity, the average size of which can vary in the range from 100 to 500 nm. Then, by self-assembly technique, we deposited the beads of polymethylmethacrylate into ordered matrices (templates), mainly with a face-centered cubic lattice. The resulting mesoporous structures, called artificial opals or colloidal crystals, had lateral dimensions of about 10 × 10 × 2 mm. Then we heat-treated the opals to 120 °C to harden the template before being impregnated with the precursor. Further, we impregnated the opals with silica sol with a particle size distribution from 1 to 5 nm, obtained by hydrolysis of tetraethoxysilane in the presence of hydrochloric acid, and then, after curing and drying the impregnating composition in air at room temperature, we multi-stage fired them up to 550 °C at normal pressure in the air atmosphere to remove all organic components. As a result, the macroporous metamaterial (the so-called inverse opals) with an open system of pores up to 400 nm in size, occupying about 80 % of the volume, were obtained. We studied lactic acid bacteria of cucumber brine and human red blood cells with TM4000 Plus, SU3500 and S-5500 scanning electron microscopes. Auxiliary substance for the sample preparation was ionic liquid VetexQ EM (Interlab LLC). We showed that it is possible to use the inverse opal as an absorbent substrate for sample preparation and rapid analysis in scanning electron microscopy without pre-drying, chemical treatment, or temperature exposure. To improve imaging in the electron microscope, we used sputter coater to cover the inverse opal surface with a thin film of platinum. The use of ionic liquid in combination with the absorbent porous medium allows preserving an original shape of the biological structures. Using the human red blood cells and lactic acid bacteria, we showed that it is possible to carry out of the morphological analysis of the cells using various scanning electron microscopes. We found that on the basis of the inverse opal, there is a fundamental possibility of creating the absorbent substrate suitable for repeated use in the study of the biological objects. At the same time, trace remnants of previous samples remaining after annealing the plate do not introduce significant distortions when conducting new series of observations. In this study, we obtained high-quality electronic micrographs of the biological objects with high resolution and contrast. At the same time, due to the use of the inverse opals as the absorbent substrate, time and financial costs for research are reduced.
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Статья обзорная
Aluminum-based alloys are widely used in many branches of modern industry (aviation, mechanical engineer- ing, shipbuilding, instrument-making, energy and medicine, etc.). The promising method for further expanding the scope of these alloys is surface treatment based on the use of concentrated energy fluxes (laser beams, plasma flows, powerful ion beams, continuous and pulsed electron beams). The purpose of this paper is to establish the possibilities of integrated electron-ion-plasma modification of the structure and properties of the surface layer of technically pure aluminum A7. The surface alloy was formed in a single vacuum cycle using the “KOMPLEX” facility (ISE SB RAS) by spraying a titanium film with a thickness of 0.5 μm and the subsequent irradiation with an intense pulsed electron beam in the aluminum melting mode. After 20 “spraying/irradiation” cycles, nitriding (540 °C, 8 h) of the formed surface alloy was performed in a low-pressure gas discharge plasma using the plasma generator “PINK”. Surface alloy studies were carried out applying the modern materials science methods (scan- ning and transmission electron diffraction microscopy, X-ray phase analysis, determination of hardness and wear resistance). The choice of elements alloying the surface layer of aluminum was based on the analysis of binary state diagrams of Al-N, Al-Ti, Ti-N systems and the isotermal section of the ternary system Al-Ti-N. It has been shown that formation of an entire series of binary and ternary compounds, including MAX-phases of the composi- tion Ti2AlN and Ti4AlN3, is observed under equilibrium conditions in the Al-Ti-N system. The carried out research has allowed to state that an integrated method of electron-ion-plasma modification of technically pure A7 alumi- num by nitriding (540 °C, 8 h) of the surface alloy formed by pulsed melting in vacuum of the Al-Ti system (20 “spraying/irradiation” cycles with an electron beam with parameters 10 J/cm2; 50 μs; 10 pulses; the titanium film thickness in each cycle 0.5 μm) leads to formation of a multiphase multielement submicro-nanocrystalline surface layer up to 20 μm thick. It is shown that the mechanical (microhardness) and tribological (wear resistance and friction coefficient) properties of the formed surface layer exceed manifold the properties of the original commercially pure aluminum A7.
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Статья научная
The paper describes materials based on solid solutions GdxMn1-xS and GdxMn1--xSe, which in the future can be used in aerospace industry as sensors, detectors, and information writer-readers. In solid solutions GdxMn1-xA (A = S, Se) (x ≤ 0.2), capacitance and tangent of the dielectric loss angle were meas- ured at the frequency of 10 kHz without a magnetic field and in the magnetic field of 8 kOe in the temperature range 100-500 К. The growth of the dielectric permittivity and the maximum of dielectric losses in the low-temperature region were observed. The displacement of the temperature of the maximum of the imaginary part of the permittivity in the direction of high temperatures is found with increasing concentration. For two compositions, a magnetocapacitance effect was observed. The magnetocapacitance effect δεН = (ε(Н,T)-ε(0,Т))/ε(0,Т)) was determined as a result of inves- tigation of the complex dielectric permittivity. The synthesis of new chalcogenide compounds in the cationic substitution of manganese by gadolinium in the MnS and MnSe systems will make it possible to clarify the effect of the anion system, as a result of studying its magnetoresis- tive properties with concentration in the gadolinium ion flux region along the x ≤ 0.2 lattice. Dielectric losses are described in the Debye model with the freezing of dipole moments and in the model of orbital- charge ordering.
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Статья научная
Numerical values of factors of viscosity, elasticity and plasticity of a media are established. Experimental dependences of viscosity and elasticity of environment on degree of its filling and granularity of abrasive grains are revealed.
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Factor analysis of inelastic electron scattering cross section spectra of iron monosilicide FeSi
Статья научная
The inelastic electron scattering cross-section spectra of FeSi silicide were calculated from the experimental re- flected electron energy loss spectra as the product of the average inelastic mean free path and the differential cross section of the inelastic electron scattering. To inelastic electron scattering cross-section spectra study, factor analysis was used. This method allowed us to quantitatively separate the surface and bulk contributions to the spectra, and de- termine the energy of the bulk plasmon more accurately than it is possible using traditional methods. Inelastic electron scattering cross-section spectra (Kλ-spectra) are the products of the average inelastic mean free path λ and the differential inelastic scattering cross-section K (E0, E0 - E), where E0 and E are the energies of the pri- mary and reflected electrons, respectively. The advantage of inelastic electron scattering cross section spectroscopy is that, unlike the reflected electron energy loss spectra, the Kλ-spectra exclude losses due to multiple excitations, and the intensities are determined in absolute units. These spectra are also more sensitive to changes in the energy of the pri- mary electrons and the angle of emission. Inelastic electron scattering cross-section spectroscopy allows to determine the element composition with much greater accuracy than the traditional method of reflected electron energy loss spec- troscopy. In this work, factor analysis is used to study the inelastic electron scattering cross section spectra of the FeSi sili- cide. This method allowed to solve the actual problem of separating spectra into contributions of a different origin, quantify them and determine the energies of a bulk plasmon more accurately compared with traditional methods. The study of electron energy loss processes by isolating contributions of different origin in the inelastic electron scattering cross section spectra is one of the urgent problems of electron spectroscopy, which can be used to assess the effect of surface excitations in REELS, XPS and AES.
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Features of electroactivated water production at a coaxial electrode location
Статья научная
Important characteristics of any product are quality and reliability. One of the factors affecting product reliability is the surface cleanliness provided by flushing with liquids. Electroactivated water and aqueous solutions can be used as liquids. On the basis of domestic and foreign experience, leading experts have developed methodological instructions for the widespread implementation of electro-activated water and aqueous solutions in instrument-making and mechanical engineering. For the production of electrochemically activated water and solutions, non-flowing and flow- through modular elements, as well as universal installations, have been developed. Analysis of the structures of these devices has shown that flat metal plates are used as electrodes, therefore there are volumes of water that are subjected to uneven electrical effects. As a result, the specific energy consumption for obtaining activated water is significant. The purpose of the work is to reduce the specific energy consumption in the production of activated water and aqueous solu- tions. Coaxial arrangement of the electrodes leads to reduction in energy consumption. The study of the electroactiva- tor of water with a coaxial arrangement of electrodes allowed us to establish the optimal ratio between the volumes of anolyte and catholyte and the time of electrolysis of water and an aqueous solution of sodium chloride. A new indicator of efficiency (the specific energy consumption per unit of change in the pH of water or an aqueous solution) objectively reflects the perfection of the design of electroactivators. The research results can be used in instrument and mechanical engineering.
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Features of synthesis of composite material based on silicon dioxide and carbon nanotubes
Статья научная
Today, there are many papers showing the effectiveness of the use of carbon nanotubes as additives to composites. Their use in polymers is especially successful, but the efficiency of their use in ceramics poses many questions. The aim of the work was to study the effect of the addition of carbon nanotubes on the properties of ceramics. For this purpose, pure silica, obtained by the hydrolysis of tetraethoxysilane in an alkaline medium, was taken as a model. The obtained granules of the material were well sintered at 900 ° C and it was decided to compound this material with carbon nano- tubes. Depending on the method of introducing, the result turned out to be diametrically opposite. Nanotubes intro- duced during the synthesis of silica played a role in the formation of silicon dioxide grains and effectively compacted the material, increasing its hardness. On the contrary, nanotubes grown in ceramic pores wedged the grain of silicon dioxide, making the material softer. In the first case, it is important to note that the synthesis of ceramics is not affected by the synthesis of nanotubes. In turn, nanotubes always affect the process of forming ceramics. This influence leads to a change in the structure of the grains of ceramics, and as a consequence of the mechanism of interaction between them, which in turn changes the density and strength of the ceramics. In the second case, in order to grow nanotubes in the pores and cavities of the ceramic material, one must first im- pregnate the ceramic material with a catalyst. Thus, there is a requirement for a precursor of the catalyst - the absence of its interaction with ceramics. The second requirement is for inertness of the ceramics, both to the catalyst and to the entire synthesis process. In addition, it is necessary that the structure of the pores does not change during the synthesis, i.e. they did not close during the synthesis of nanotubes, but provided transportation of the starting materials and reac- tion products. Therefore two mechanisms that affect the formation of a composite ceramic material have been described. The described composite can be used in the rocket and space industry for compounding ceramic fairings and thermal insu- lation.
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![Formation features of the central layers of the alloy Fe - 3 % Si (110)[HKL] rolling textures](/file/thumb/148321932/formation-features-of-the-central-layers-of-the-alloy-fe3-si-110-hkl.png "Formation features of the central layers of the alloy Fe - 3 % Si (110)[HKL] rolling textures")
Formation features of the central layers of the alloy Fe - 3 % Si (110)[HKL] rolling textures
Статья научная
The fields of solid-state physics, metallurgy, plastic deformation, mathematics and continuum mechanics are engaged in the studies of texturing of metals and alloys and their influence on the operational properties of products. As a rule, the most significant results are expected at the interface between these sciences. The technologies of obtaining textured materials by metal forming processes occupy a special place in the metalworking sphere. This is due to promising directions in technologies for producing semi-finished and final products with improved structure-sensitive properties, by regulating the texturing, taking into account initial crystallographic orientation of the workpiece. The first issue to note is the formation of an ideal, one-component crystallographic texture in anisotropic metallic materials. The second issue is to obtain semi-finished and final products with more specific service properties: crystallographic texture with specific predetermined components. For instance, due to the crystallographic texture, it is possible to increase the resistance of metals and alloys against corrosion and hostile environment. Considering textured materials as composite, we must note that directionally oriented crystallites with crystallographic direc- tions relative to the laboratory direction perform as reinforced elements. The initial texture in the processing plane is especially important. The materials, which possess unique structure-sensitive properties acquired through pressure treatment, are very promising for a widespread use in the sphere of aerospace technology. Obviously, the properties and means of their achievement are diverse and require setting a specific task. Therefore, further research in this sphere is especially promising. The article presents the research findings, considering the effect of initial crystallographic orientation and deformation modes on the rolling texture in the central layer of Fe - 3% Si (110)[ hkl ] single crystals. Several groups of single crystal samples underwent rolling under laboratory conditions. The groups of samples were classified according to the final deformation rate, the ideal crystallographic orientation of the rolling plane and deflections of the ideal orientation plane direction from the rolling direction. The methodology of the experiment took into account the compression rate value during one rolling. We analyzed the results of rolling, using the radiographic method. The next step was to superimpose the radiographic data on a stereographic projection and to construct straight pole figures. The results of straight pole figures decoding revealed differences in the texture formation from the previously obtained data. The research shows the manifestation of the one-component deformation texture in the central layer.
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Статья научная
The use of thermal-cycle processing improves the mechanical properties of boat screws of aluminium-silicon alloy АК12.
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Статья научная
The paper presents the results of the introduction of a coding system for violations of technological discipline in the organization by making a statistical analysis of violations. Compliance with technological discipline is a necessary condition and basis for ensuring the required quality of manufactured products. Breaking the discipline leads to the production of defective goods, to a decrease in product quality, to deterioration of working conditions, and to accidents and breakdowns of technological equipment. In this paper, we present the procedure for analyzing recurring violations based on the collected data from 12 production departments of one organization. For the implementation of the coding system the authors collected, processed and analyzed data using statistical methods such as a checklist, a histogram, a Pareto chart, a diagram of the causes and results. The use of statistical methods does not require large expenditures and makes it possible to judge the state of the phenomena (objects, processes) with a given degree of accuracy and reliability. An important feature of the application of the presented methodology is the ability to predict and regulate problems at all stages of the product life cycle and, on the basis of this, to develop optimal management decisions. Sta- tistical methods are effective tools for collecting and interpreting data, as well as analyzing quality information. Coding violations of technological discipline makes it possible to identify recurring violations, develop corrective and preventive actions, both at the level of the production department and at the level of the organization as a whole. The results obtained are of considerable interest and can be used both at enterprises of space industry and at other engineering enterprises.
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Статья научная
In this work, the effect of ZrO 2 nanoparticles prepared in a low-pressure arc discharge plasma on magnetic flux pinning of granular YBa 2Cu 3O 7-y/nanoZrO 2 composites has been studied. It has been shown that the ZrO 2 nanoparticles do not change the superconducting transition and the microstructure of superconductors. At a temperature of 5 K, the addition of 0.5 and 1 wt % of ZrO 2 nanoparticles may lead to the additional effect of magnetic flux pinning and the increase in the critical current density J c. The J c value for composites with 1 wt % is two times larger than that for the reference sample. The fishtail effect is observed for YBa 2Cu 3O 7-y/nanoZrO 2 composites at the temperatures of 20 and 50 K. The problems associated with the additional effect of magnetic flux pinning of granular YBa 2Cu 3O 7-y/nanoZrO 2 composites and the appearance of the fishtail effect have been discussed.
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Статья научная
The modern solar arrays for the most spacecrafts consists of solar cells which are formed by the thirty nano- and micro-dimensional epitaxial layers based on AIIIBV materials forming triple junction InGaP / InGaAs / Ge. This article presents the results of a study of experimental samples of thin single-crystal epitaxial InxGa1-xP layers with different indium and gallium concentrations (x = 38 to 53 %) that were grown on Ge - substrate by MOCVD industrial equip- ment. The theme of present investigation is the influence of epitaxial growth parameters on the crystal structure charac- teristics. The ratio of the components of the third group in the gas phase were calculated from the specified technological parameters. The rocking curves obtained by high-resolution two-crystal X-ray diffractometry were investigated. The lattice parameter and the ratio of indium to gallium in the solid phase were calculated. A high perfection of a single- crystal structure with an insignificant broadening of the X-ray diffraction peaks was observed in the range from 45 to 53 %. It is shown that the broadening of the diffraction peak of the structure can be the criterion of estimation of the quality of the grown structure in addition to the mismatch of diffraction maximum. Also the In / (In + Ga) ratio in the solid phase was calculated using the method of photoluminescence effect measuring. It was shown in comparison of data of x-ray diffraction with photoluminescence method the composition determination by photoluminescence method should be considered only as estimated.
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Interaction of magnetic and dielectric subsystes in a bismuth nodymic ferrite-granate
Статья научная
Bismuth-substituted ferrite garnets possess magneto-optical (MO) properties and are used as spatial light modula- tors and indicators. The paper studies the influence of magnetic and electric fields on the structural characteristics of thin epitaxial films of bismuth-neodymium ferrite garnet (Bi: NIG) deposited on glass and gallium gadolinium garnet (GGG) substrates. Dynamic properties of polarization, relaxation in a magnetic and electric field are considered, which is an important task for getting a deep insight into the mechanisms of electromagnetic phenomena in solids. Dependence of the magnetostriction coefficient on the magnetic field and dependence of a relative change in the length of the film on the electric field at different temperatures are obtained. A change in the sign of magnetostriction constants with respect to temperature was found. The electric polarization in a periodically applied electric field of 400 V / cm with a frequency of 10 MHz is determined for various magnetic field orientations of 12 kOe and in the absence of a magnetic field. Anisotropy of polarization in a magnetic field and a functional dependence of the polariza- tion relaxation on time are found. These materials can be used as sensors of the magnetic field in a spacecraft.
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Статья научная
This paper is devoted to the high-effective process of surfacing by the indirect three-phase arc with covered electrodes. The share of the parent metal in the surfaced one does not exceed 10 % which is infeasible for one-arc surfacing.
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Статья научная
The impact of magnetic fields caused by thermoelectric currents and residual magnetization of the welded parts on the accuracy of an electron beam positioning along the welded joints is a complicated scientific and technical problem to achieve high quality of welds in the aerospace industry, shipbuilding and power engineering. Presented in the article mathematical models of distribution of magnetic fields of interference in the space between the electron beam gun and the surface of a welding workpiece and also inside a workpiece allow to culculate the quantitative characteristics of the electron beam deflection from welded joints. The authors propose to use a deflection system for compensation of mag- netic interference impact. The deflection system must be set to a certain height above the workpiece to be welded. The authors obtained a mathematical model of the magnetic field induction of the deflecting system distribution along its axis which coincides with the optical axis of the electron beam gun. The coordinates of installation of the deflection system concerning the surface of the parts to be welded are determined using the presented mathematical models. Cal- culations showed that the height of installation of deflection system depends on the thickness of the welded components. Using the deflection system installed at a certain height above the workpiece to be welded allows to eliminate the impact of magnetic fields caused by thermoelectric currents and residual magnetization of the welded parts on the quality of welded joints.
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Laboratory separator of bulk materials
Статья научная
New materials for spacecraft radiation screens engineering require a fine classification of powder materials by particle size. The article concerns the construction of powder materials laboratory separator. This type of material separation is related to gravity methods. The Moseley laboratory separator serves as the prototype of the construction with table longitudinal shaking and diametrical vibrations by means of buffers during the separation process. The unbalanced oscillator yields deck separation surface harmonic vibrations in all directions. The unbalanced oscillator DC motor voltage control gradually alters the vibration frequency and supports finer separation of the material. A power pipe enables to conduct perpetual separation process. In prototype, in contrast, up to 100 g weight is processed for up to 5 minutes. To improve the materials fine and small classes separation efficiency, riffles are made on the separation surface, which determine the places of concentration of material particles. As a result of the conducted researches for elimination of the secondary circulation flows, a system of diametrical reefing is worked out: the riffle is approximately equal to the maximum particle size of the separated material and is equal to 0.2 mm in this construction; the distance between riffles is equal to 50 mm, the tilt angle is 80 degrees relative to the deck longitudinal side. The particle motion depends on the inclination angle of the separation surface. Large particles move upwards at angles of up to 5 degrees, and downwards at angles higher than 5 degrees. Vibration frequency and amplitude alteration, as well as adjusting the inclination angle of separation surface enables to move and adjust the speed of different properties and sizes of test material. The laboratory separator work is based on the physical effects, which enable to vary the location of the power pipe. This fact allows the construction to be adapted to a variety of specific conditions and expands the construction sphere. The separator construction is simple for production and operation, and can be quickly reconfigured if necessary. The separator portability allows it to be transported.
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