Articles

 


№1 | №2 | №3 | №4 | №5 | №6 | №7 | №8 | №9 | №10 | №11





1.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-3-11
УДК 669.721.5
Duyunova V.A., Molodtsov S.V., Leonov A.A., Trapeznikov A.V.
APPLICATION OF COMPUTER MODELING METHODS IN THE MANUFACTURE OF COMPLEX-CONTOURED SHAPED CASTING

The purpose of this article was to demonstrate the advantages of computer-aided design (CAD), the example modeling casting details for its production of Ml5pch alloy by sand casting.

The model casting was developed with the help of program complex SolidWorks. For the resulting model casting was designed core boxes and tooling for the manufacture of sand molds. Also, as the configurations of the model was provided for the three most optimal variant of connecting the metal to casting.

 For the part were calculated in the software package of computer simulation of casting processes ProCast to determine the best variant of the Gating system. According to the calculations were selected Gating system to ensure the absence of casting defects.

After the full model calculation, the selected method of manufacturing a casting, was printed using additive manufacturing equipment, manufactured and assembled sand cores and mold halves. Then, magnesium alloy ML5pch casting was carried out.

The analysis of the geometry of the resulting castings showed that the use of CAD when designing castings and snap prevented the probable defects (nonfill, deviations from geometric dimensions, Shrinkage depression, etc.). Also, the using of CAD has reduced the cycle time to manufacture the part and to reduce the likelihood of marriage.

The obtained castings have been tested on radiographic non-destructive testing. According to the results of decoding of x-ray images of microremote and other defects were detected.

In the progress of the work was demonstrated the main advantages of CAD, namely the visibility of the design and calculations, the possibility of changes to the model casting and tooling at any stage of the design process.

Read in Russian

2.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-12-21
УДК 669.017.165:669.245
Rodionov A.I., Efimochkin I.Yu., Samokhin A.V., Sinayskiy M.A.
THE INFLUENCE OF THE SPHEROIDIZATION PROCESS ON THE FRACTIONAL COMPOSITION AND MORPHOLOGY OF ALLOY VKNA-4U IN A PARTICLE-REINFORCED SHEATH Al2O3–Y2O3

This article discusses the influence of the spheroidization process on the morphology, microstructure and fractional composition of the VKNA-4U alloy reinforced with Al2O3-Y2O3 particles.

For the study, the matrix alloy VKNA-4U reinforced with nanosized powder Al2O3-Y2O3 was used. The matrix alloy was melted from the initial charge blanks for VKNA-4U alloy in an induction furnace. Obtaining powder matrix alloy VKNA-4U carried out by the method of gas atomization. Nanosized oxide Al2O3-Y2O3, was obtained in the plasma torch at the Institute of Metallurgy and Materials Science named A.A. Baykova RAS. Mechanical alloying of the powder alloy VKNA-4U and the hardener Al2O3-Y2O3 was carried out in an attritor. The powder processing of the alloy VKNA-4U reinforced with dispersed particles Al2O3-Y2O3 was processed in a plasma-chemical installation.

Plasma processing when creating spherical composite cermet powders allows to correct machining defects - to make the shape of particles more round and smooth, thereby improving the fluidity of the material, due to the melting of the matrix material and for better contact of the particles of cermet powder with further compaction.

During the experiment, it was found that the process of spheroidization significantly affects the morphology of the particles. Studies show how the morphology of particles changes. After machining, the particles have a fragmentation shape. Due to the process of spheroidization, the particles take a rounded shape, which affects such a parameter as fluidity, which is necessary for use in plants for additive manufacturing.

When analyzing the microstructure, it was found that the particles of the reinforcing f

Read in Russian

3.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-22-36
УДК 678.8
Kolpachkov E.D., Petrova A.P., Kurnosov A.O., Sokolov I.I.
METHODS OF MOLDING AVIATION PRODUCTS FROM PCM (review)

The basic methods of molding PCM products are considered. For a more detailed analysis of the distinctive features, advantages and disadvantages, it is proposed to consider methods for obtaining products from PCM in accordance with the classification:

– prepreg methods – methods of molding products from polymer composite materials in which prefabricated semi-finished products are used – prepregs, reinforcing fillers, impregnated with a binder; among these methods, the article examined: pressing, autoclave molding, the automated strip laying method (ATL – Automated Tape Laying) and the automated fiber laying method (AFP – Automated Fiber Placement);

– direct process (direct process) – methods of forming products from polymer composite materials, which do not require preparation of the prepreg, due to which the molding takes place in one technological cycle, in the amount of forming equipment; among these methods, the article examined: infusion, pressure impregnation (RTM – Resin Transfer Molding), film binder impregnation (RFI – Resin Film Infusion);

– other methods – this class of processing methods includes methods in which the use of prepregs is not mandatory, and with certain technological features with these methods, the molding of a product can be carried out in one technological operation; also, molding methods were assigned to this class, the use of which to obtain PCM products for use in the aviation industry is not advisable, due to insufficient control of the parameters of the molded product during production and, as a result, the high probability of obtaining the final product, with properties not satisfying product requirements; among these methods, the article examined: winding method and contact molding methods (manual calculation method and calcu

Read in Russian

4.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-37-43
УДК 678.8
Kovalenko A.V., Sidelnikov N.K., Sokolov I.I., Tundaykin K.O.
SPHEROPLASTIC WITH ADJUSTABLE VISCOSITY FOR FILLING SECTIONS OF HONEYCOMB STRUCTURES

The use of polymeric spheroplasts on the basis of new high-strength binders in the composition of multilayer structures with carbon or fiberglass casings with a high level of physicomechanical, dielectric and thermal characteristics in various operating conditions, including when exposed to high temperatures and in conditions of high humidity, opens broad prospects. In addition to ensuring the process of combining the elements of honeycomb structures, spheroplast during operation participates in the perception and transmission of acting loads, while maintaining the specified level of strength and durability of the joint. To obtain a spheroplastic filler, the study of the rheological behavior of a polymer base based on epoxy oligomer and the effect of dispersed fillers on the viscosity of the material is required. Epoxy oligomer should have a reduced viscosity at temperatures up to 100 ° C for the smooth introduction of dispersed fillers and reduce the load on the equipment during the synthesis of the polymer base. The paper presents 2 methods for regulating the viscosity of spheroplasts: the first method is to change the ratio of the content of hollow glass microspheres, the second is based on the addition of a highly dispersed component of aerosil. This method is very effective in those cases where high requirements for weight and improved compressive strength properties are imposed on the cured spheroplasty.

As a result of the work carried out, the choice of parameters was made and the ratios of the components of aggregate-spheroplastic brand VZ-21 were calculated. Samples of the polymer base and spheroplastic filler brand VZ-21 were manufactured and investigated.

The spheroplastic filler of the brand VZ-21 is designed to fill sections of multi-layer honeycomb structures in order to improve the physicomechanical characteristics of aircraft wing mechanizati

Read in Russian

5.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-44-52
УДК 666.7
Sidorov D.V., Shavnev A.A., Solodkin P.V., Kirilin A.D.
QUANTUM CHEMICAL CALCULATION OF INTERMOLECULAR INTERACTION METHYLSILANE MOLECULES DURING THE PYROLYSIS PROCESS

The article is assigned at improving methods and technologies for the manufacture of composite with high technical characteristics. This is facilitated by the acquisition of new knowledge in the field of physicochemical processes, the mechanisms of chemical reactions and the causes of their occurrence, the reactivity of substances, the spatial structure of molecules by quantum chemical calculation of molecules. In literature, the process of pyrolysis of methylsilane to silicon carbide is described from the point of view of intramolecular interaction and the formation of intermediate compounds. However, there are many methylsilane molecules in the system that can also interact with each other.

The aim of this work was to estimate the possibility of intermolecular interaction of methylsilane molecules by the method of non-empirical quantum-chemical calculation and determine the most preferred reaction pathway. In the interaction of two methylsilane molecules in the gas phase, three main variants of intermolecular reactions with the evolution of molecular hydrogen and the formation of the following compounds can be considered: 1,2-dimethyldisilane, (2-silylethyl)silane, methyl(silylmethyl)silane.

For the proposed compounds, a quantum chemical calculation was performed non-empirically using the basic set 6-311+G (d) and the second-order Moller–Plesset perturbation theory, the geometry of molecular structures was optimized, and thermodynamic data were calculated.

Analyzing the calculated thermodynamic data of chemical reactions, it was found that the formation of 1,2-dimethyldisilane and (2-silylethyl) silane is endothermic. The formation of methyl (silylmethyl)silane by a chemical reaction is exothermic. According to the results of calculations of thermodynamic characteristics, we can

Read in Russian

6.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-53-59
УДК 669.018.95
Nyafkin A.N., Loshinin U.V., Kurbatkina E.I., Kosolapov D.V.
INVESTIGATION OF INFLUENCE OF SILICON CARBIDE FRACTIONAL COMPOSITION ON THERMAL CONDUCTIVITY OF COMPOSITE MATERIAL BASED ON ALUMINIUM ALLOY

The work is devoted to the development of technology for the manufacture and research of thermal properties of samples of metal composite material based on aluminum casting alloy brand AK7 system Al-Mg-Cu-Si with a content of 64 to 66 percent volume of silicon carbide and different fractional composition of powders grades F60 (particle size 320–250 microns), F120 (particle size 125–100 microns) and F220 (particle size 63-50 microns). Measurements of the characteristics of thermal properties: heat capacity, thermal conductivity and thermal conductivity, in the temperature range from - 100 to 400 °C, a composite material with different fractional composition. The thermal conductivity of the composite material based on powder grade F60 190,4 W/(m·K) with a particle size of 320–250 microns, F120=184,2 W/(m·K) with a particle size of 125–100 microns and F220=150,0 W/(m·K) with a particle size of 63–50 microns. It is found that with increasing particle size fraction thermal conductivity increases by 15–20% at 20°C, due to the low content of interfacial boundaries heterogeneous structure of the composite and thus decreases the volume content of the pores. The increase in the specific weight of the workpiece can be achieved, as is known, due to the denser packaging of the briquette under a high pressure press, either using a polyphonic powder mixture, or using both of these methods. The dependence of the influence of the deformation effect on the formation of the workpiece of a given porosity depending on the size of the carbide phase particles, as well as the influence of the size of the carbide phase particles on the impregnation of the porous workpiece matrix alloy melt by vacuum-compression impregnation. Methods of determination of a complex of thermophysical properties are fulfilled: heat capacity, thermal conductivity and thermal conductivity, in a temperature range f

Read in Russian

7.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-60-67
УДК 537.622.4
Koplak O.V., Kunitsyna E.I., Valeev R.A., Korolev D.V., Piskorsky V.P., Morgunov R.B.
FERROMAGNETIC MICROWIRES α-Fe/(PrDy)(FeCo)B FOR MICROMANIPULATORS AND POLYMER COMPOSITES

Presents results of a study of magnetic properties of ferro-magnetic microwires a-Fe/(PrDy)(FeCo)B, which contains the core α-Fe and the surface layer of the amorphous phase (PrDy)(FeCo)B. extraction Method hanging drop of melt (PrDy)(FeCo)B was used to obtain microwires with a homogeneous surface and cylindrical geometry. The optimal values of the share of the amorphous magnetic phase and the length of the microwire are found that meet the conditions of magnetic bistability, which opens the possibility of their use as micromanipulators and polymer composites. In this paper, the rare earth alloy was used in the ultrafast cooling mode, when the phases are separated into a core of transition metals and an amorphous shell with almost zero coercive force. By doping Pr and Dy and forming an amorphous phase, fine-tuning of the maximum energy product becomes possible. Microwire, as a rule, contained a core of polycrystalline phase α-Fe (52% ) and amorphous alloy shell (PrDy) (FeCo)B (~48 vol. %). This distribution of the chemical composition of the phases in the microwire is caused by the high cooling rate of the melt ~106 К/c. micro-Dimensional structures, where the polymer matrix acts as a dielectric medium and the microwires as sensing elements, demonstrate excellent magnetic impedance characteristics and high microwave absorption. Local magnetic hysteresis loops obtained by Kerr microscopy show a symmetrical loop close in shape to the rectangular loop in the center of the microwire and an asymmetric loop similar to that obtained in the SQUID magnetometer when shortening the microwire of less than critical length. This confirms the applicability of the classical concepts of the domain structure of magnetic microwires as single-domain objects with multi-domain regions at the ends of the microwire.

Read in Russian

8.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-68-74
УДК 678.745.32
Timoshkov P.N., Sevastyanov D.V., Usacheva M.N., Khrulkov A.V.
EXISTING AND PROMISING TECHNOLOGIES FOR PRODUCING PAN FIBERS (review)

To create carbon fibers, raw materials, polyacrylonitrile fibers, are needed. Fiber production is expensive and environmentally unsafe due to the use of a large amount of volatile organic solvents.

Polyacrylonitrile is obtained by polymerization of acrylonitrile or by copolymerization of acrylonitrile with unsaturated monomers (from 15 to 65% by weight).

There are several copolymerization methods: in solution, in emulsion, in suspension or melt. Each of the methods has its advantages and disadvantages.

It is advisable to carry out copolymerization in a solution in a solvent that dissolves both the polymer and the monomer; the production technology is continuous and simple.

During emulsion copolymerization, the polymer has a wide molecular weight distribution, the method is used to obtain copolymers.

With suspension - it is possible to vary the composition of the copolymers in a wide range, the polymer does not have low molecular weight residues.

The method for producing PAN in the melt is affordable, but limited due to the autocatalytic nature of the process and high viscosity.

The fibers are formed by three methods: wet, dry (and its type of electrospinning), dry-wet and melt. All of them (except for electroforming) are based on the production of polymer filaments by forcing liquid polymer through the holes of the die into a solution that causes the polymer to coagulate, after which the filaments solidify.

In the dry method, the filament is formed in a spinning mill, where, under the influence of temperatures, the solvent evaporates from the fibers. During electroforming, fibers are formed by electric forces.

<p style="text-align: j

Read in Russian

9.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-75-84
УДК 66.017
Davydov D.M., Titov V.I., Letov A.F., Lutsenko A.N.
COMPARATIVE EVALUATION OF METHODS FOR DETERMINING THE CONTENT OF HYDROGEN IN METAL MATERIALS

In this work, we evaluated three methods for determining the hydrogen content in metallic materials: optical emission, heating in a carrier inert gas with a conductometric end and vacuum heating with a mass spectrometric end. Also, we consider the optimal field of application of each of the considered methods for solving specific tasks aimed at determining the hydrogen content with different binding energies (total, diffusion-mobile, strongly bonded) in metallic materials.

The optical emission method is sufficiently productive, but has the lowest accuracy and sensitivity of those considered. Another disadvantage of this method is that it is applicable only to the analysis of alloys based on titanium. The advantage of the method is the high locality and the ability to analyze the samples studied in layers. Therefore, it is indispensable in determining the degree of hydrogen absorption of the surface of the titanium alloy after the etching process.

The method of heating in a stream of inert gas carrier to determine the hydrogen content is the most productive in terms of the number of samples studied. It has a satisfactory level of accuracy. The disadvantages of the method include the high cost of consumables and mediocre sensitivity in the case of analysis, for example, aluminum alloys. It is recommended for the serial analysis of a large number of metal samples on one basis.

The most difficult to master is the method of vacuum heating with a mass spectrometric ending. At the same time, it has the highest accuracy and sensitivity, but the lowest performance. Allows you to analyze any inorganic materials and separate hydrogen by bond energy. This is important for the study of the dependences of the effect of different hydrogen contents with different binding energies on the structure o

Read in Russian

10.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-85-94
УДК 620.193:669.715
Abramova M.G., Goncharov A.A.
CRYSTALLINE CORROSION DEFORMABLE ALUMINUM ALLOYS DURING NATURAL AND NATURAL ACCELERATED CORROSION TESTS

Operation of structural elements made of aluminum alloys in an aggressive atmosphere, which are environments with a high content of chloride ions in combination with high humidity, is associated with the risk of corrosion damage, which, if invisible to the naked eye, can lead to loss structural bearing capacity and the occurrence of failures due to mechanical failure.

The most dangerous types of corrosion failure of aluminum alloys are intergranular corrosion (IGC), which develops along the grain boundaries (crystallites) deep into the metal. The center of intergranular corrosion is most often the center of failure upon application of mechanical stresses. Reducing the propensity for aluminum alloys to IGC is one of the priority tasks in the development of materials, and is achieved mainly due to the selection of the heat treatment mode, while maintaining a high level of mechanical properties is an indispensable condition.

The present work is devoted to summarizing the results of climatic tests under conditions of a moderately warm climate of aluminum alloys with the study of the influence of the degree and nature of the development of IGC on the change in the mechanical properties of sheet semi-finished products depending on the alloy system. Typical MKK images are given that are characteristic for alloys of Al-Cu-Li systems; Al-Cu-Mg; Al-Mg-Si; Al-Zn-Mg-Cu; Al-Mg. Based on the analysis of the available volume of the results of assessing the tendency to IGC and the corresponding loss of mechanical properties, the dependences of the change in the tensile strength and relative elongation depending on the depth of the IGC for sheets of aluminum alloys with a thickness of 2 mm are obtained. It is also shown that the depth of the IGC is directly dependent on the geometric dimensions of the grain, while the standard deviation characterizing the dispersion of grain siz

Read in Russian

11.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-95-103
УДК 620.179
Golovkov A.N., Kulichkova S.I., Kudinov I.I., Skorobogatko D.S.
ANALYSIS OF EXISTING TEST PIECES FOR TESTING OF SENSITIVITY OF FLAW DETECTION MATERIALS DURING PENETRANT TESTING (review)

Penetrant testing is one of the most common and sensitive methods of non-destructive testing of surfaces. The sensitivity of penetrant testing is conventionally determined by the smallest values of disclosure, depth and length reliably identify real or artificially initiated by defects in their flat track.

To assess the sensitivity of flaw detection materials in penetrant testing, test pieces are used, which are metal plates with a certain surface roughness and normalized artificial defects applied to them. The manufacturing technology of such pieces consists in obtaining surface cracks of a given depth, the width of which is close to the sensitivity threshold of the penetrant testing method used, while ensuring the stability of the crack sizes and material properties during the specified service life, the resistance of pieces to corrosion when exposed to flaw detection materials. On the basis of the analysis it is established that the most common are the pieces made of sheet alloy steel with cracks in nitrided layer.

Abroad, paired chromium-Nickel test panels are used to study and compare sensitivity. The panel is a brass plate with a Nickel-chrome coating of a given thickness, on which very small transverse cracks with a precisely specified depth are created.

According to the results of the review, it was found that checking the flaw detection kit for sensitivity using existing test pieces, it is impossible to say that the same sensitivity of penetrant testing will be guaranteed during the given technological process. As standards, it is advisable to use pieces of the same material as the test parts, taking into account the nature of the flaw formation, material and surface treatment of the test part (roughness), with defects whose disclosure value is close to the sensitivity threshold of the applied method of penetrant tes

Read in Russian

12.
dx.doi.org/ 10.18577/2307-6046-2019-0-11-104-112
УДК 582.288.4
Krivushina A.A., Bobyreva T.V.
PROPERTY PERSISTENCE OF «KEROSENE» FUNGUS HORMOCONIS RESINAE STRAINS DURING LONG-TERM STORAGE IN THE LABORATORY

The species Hormoconis resinae or «kerosene fungus» is known for its ability to cause biodeterioration of aviation fuel and fuel system materials. Cultures of this fungus are actively used to test the fungal resistance of fuels and biocide additives to fuel according to State Standard 9.023–74 « Unified system of corrosion and ageing protection (USCAP). Fuel oil. Method of laboratory testing biostability of fuels protected by antimicrobial additive». The collection of FSUE «VIAM» contains 7 strains of the Hormoconis resinae species, isolated from different climatic zones and of interest for extended testing and comparative studies. Until recently, the method of subcultivation on nutrient media was used for their storage, the disadvantages of which include a rather high probability of losing the necessary physiological properties of the culture. The aim of this study was to test the physiological properties of «kerosene fungus» strains after years of storage on nutrient media for their transfer to a long-term duplicate collection of lyophilization and cryogenic freezing methods.

Physiological activity of micromycetes was assessed visually, according to the characteristic signs of growth described in State Standard 9.023. The results of inoculation of two types of aviation fuel RT and TC-1 by Hormoconis resinae 7strains (№viam44, viam57, viam58, viam59, viam79, viam179, viam180) for 3 months showed that all strains retained their ability to grow due to aviation fuel hydrocarbons. However, the lag phase increased significantly, or the time required to starting active growth in fuel, it ranged from 1 to 3 months. Re-isolated cultures showed signs of growth in the first two weeks, thus, the activity of the cultures was fully restored.

Since the fungal resistance tests duration according&

Read in Russian