Articles

 


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1.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-3-11
УДК 669.017.165:669.245
Sevalnev G.S., Gromov V.I., Eliseev E.A., Leonov A.V.
INFLUENCE OF HEAT TREATMENT ON THE FORMATION OF STRUCTURE AND PROPERTIES IN THE NICKEL-BERYLLIUM ALLOY 97NL-VI

The object of investigation is the intermetallic dispersion-hardening nickel-beryllium alloy 97NL-VI. The purpose of this work is to analyze the changes in the structure and properties of the intermetallic dispersion-hardening nickel-beryllium alloy 97NL-VI, depending on the type and temperature of the heat treatment. The paper considers the change in structure and properties as a function of the heat treatment of the 97NL-VI intermetallic alloy. With electron microscopy a strengthening phase of NiBe is determined, which forms throughout the volume of the solid solution. The effect of beryllium content on the content of the intermetallic phase of NiBe in the structure of the alloy and further dissolution in the matrix with a change in the quenching temperature is analyzed. It is shown that at the quenching temperature above the eutectic transformation it almost completely dissolves the intermetallic phase, but forms an undesirable eutectic. In this regard, the best is hardening with

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2.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-12-21
УДК 669.295
Alexeev E.B., Nochovnaya N.A., Novak A.V., Panin P.V.
WROUGHT INTERMETALLIC TITANIUM ORTHO ALLOY DOPED WITH YTTRIUM. Part 1. Research on ingot microstructure and rheological curves plotting

The article contains the results of microstructure investigations in the cross section of an ingot from wrought intermetallic titanium ortho alloy doped with yttrium. It has been shown that microstructure along the generatrix of the ingot surface doesn’t differ greatly depending on the site of samples cutting and is introduced by elongated β-grains with occasional fine precipitates of α2 phase located both inside and along β-grain boundaries. In this case, an increased amount of dispersed α2 phase particles is observed in the central part of the ingot. The effect of heat treatment in a two-phase (β/В2+α2)-area on microstructure of the yttrium doped ortho alloy ingot has been studied. Heat treatment results in appearance of zones enriched and depleted with dispersed α2 phase particles in the form of disoriented plates which are observed in the central part of the ingot. The presence of such zones indicates about intragranular inhomogeneity which forms during the ingot crystallization. Intensified precipitation of α2 phase particles occurs in interdendritic spaces, the spaces being enriched by easily-melted elements (in this case – aluminum). Thermal analysis has been performed with differential scanning calorimetry (DSC) curves plotting which help to specify phase transformation temperatures of the yttrium doped ortho alloy. It has been observed that the transition from a three-phase (О+β/В2+α2)-area into a two-phase (β/В2+α2)-area takes place at a temperature of 922°С, while the transition from a two-phase (β/В2+α2)-area into a single-phase β/В2-area occurs at 1068°С. Rheological curves for the upset cylindrical samples have been plotted which revealed the deformation strain level reduction from 740 to 84 MPa with an increase of the test temperature from 850 to 1050 °C: &

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3.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-22-29
УДК 669.295
Nochovnaya N.A., Shiryaev A.A.
EFFECT OF HEAT TREATMENT ON MECHANICAL PROPERTIES AND STRUCTURE OF HIGH-STRENGTH METASTABLE β-TITANIUM ALLOY WITH EXPERIMENTAL COMPOSITION

Information is given concerning commercial use of the best-known foreign and domestic metastable b-titanium alloys in industry. The role of research in the field of hardening heat treatment for providing a high complex of physical and mechanical properties of semi-finished products and items from the mentioned class of alloys is considered. The main world tendencies in heat treatment of high-alloyed titanium alloys have been summarized.

The modes of hardening heat treatment have been chosen and the effect of various modes and technological parameters thereof on mechanical properties and structure of sheets from an experimental composition of a high-strength metastable b-titanium alloy doped with rare-earth element (REE) yttrium  have been studied.

It has been shown the possibility of wide variation within mechanical properties (ultimate tensile strength (UTS) from 820 до 1510 MPa, elongation from 21,0 to 2,6%) as well as in structural constituents parameters and morphology of the experimental alloy composition.

The research results have revealed that the experimental alloy composition can be more efficiently hardened by means of low-temperature thermo-mechanical treatment (LTMT) in comparison to conventional heat treatment.

Long-term low-temperature ageing makes it possible to provide high level of strength characteristics (UTS≈1500 MPa) while maintaining the elongation level in the range of 2–4% and satisfactory values of impact toughness. Variation in the quenching temperature (b- or (α+β)-area) didn’t have a significant effect on strength level. The quenching from (α+β)-area provided a higher level of elongation.

The application of the experimental multistage heat treatment mode gave the opportunity t

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4.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-30-38
УДК 621.74:669.715
Levchuk V.V., Trapeznikov A.V., Pentuykhin S.I., Leonov A.A.
CASTING METHODS FOR A THIN-WALLED PART FROM SILUMIN (review)

In the article the differences in the two methods of casting are described - in cold-hardening mixtures and in the case of melted models using the example of thin-walled casting "Housing" with overall dimensions 490×90×90 mm and wall thickness of 3 mm.

Shaped details with long thin walls are most rational to receive by casting with the subsequent machining. Other ways of production and production of parts – stamping, welding, cutting, additive technology – at a cost more expensive than casting. Casting in cold box process and waxed models is one of the most common methods of casting. Thus, the task of obtaining such a detail is topical.

The work involved the use of plastic equipment, obtained by 3D printing technology. The use of plastic tooling reduces casting time, but severely limits the ability of casting for investment models. It is difficult to use such a tool when machine is pressed, and when free casting, there are problems with the choice of the model mass because of its strong adhesion to the mold.

The mechanical properties of the alloy were tested on separately cast specimens in cold box process and on cut samples from cast billets over the fusible models. According to the test results, it was revealed that the properties of the AK7h alloy depend on the thickness of the billet on the cut samples. When the thickness of the workpiece is more than 12 mm, the properties are unsatisfactory. With a workpiece thickness of 10 mm, the properties of the alloy on the cut specimens are approximately equal to each separately cast.

Thus, it turned out that in order to obtain a quality casting «Housing» the most rational method of casting is casting in cold-hardening mixtures.

10.10. «Energy-efficient, resource-savi

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5.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-39-47
УДК 678.8
Petrova G.N., Perfilova D.N., Malyshenok S.V., Kuznetsova K.R.
INFLUENCE OF THE LARGE-SCALE FACTOR ON LEVEL OF PROPERTIES OF FOAMED POLYACRYLIMIDE

Until recently in elements of designs of blades of helicopters the three-layered panels consisting of two thinwalled panels from glass - or carbon fiber-reinforced plastic and cellular filler were used.

But cellular filler has number of technological and operational shortcomings (labor input of manufacturing; difficulties at formation of details of difficult configuration; high moisture absorption of three-layered panels, etc.) which can be eliminated at its replacement by alternative filler – frothed rigid plastic.

However for this purpose industrially let out foam plastics on the basis of PS, by PE, software, PU, phenolic, epoxies cannot be used, etc.: their mechanical properties strongly depend on specific weight, they are combustible, possess low warm and frost resistance.

Abroad find broad application cellular foam on the basis of thermoplastics of new generation – the polyimide possessing unique operational properties thanks to rigid structure: fire safety, high strength properties, corrosion inertness, funginertness, working capacity in the range of temperatures from -196 to 250÷350°C, etc.

Results of researches on impact assessment of large-scale factor are given in article on level of the physicist – mechanical properties rigid foamed polyacrylimide sheet VPP-5 brands.

Relevance of the conducted researches is that possibility of this or that use cellular foam in three-layered panels of constructional assignment for elements of designs of blades of helicopters is defined not only compounding of initial semi-finished product – prepolymer and structure of the foam received from it, but also stability, and size of such indicators as the apparent density and durability at compression.

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6.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-48-58
УДК 669.018.95
Serpova V.M., Grishina O.I.
STUDY OF FORMATION OF INTERMETALLIC MATRIX STRUCTURE BASED ON HEAT-RESISTANT NICKEL ALLOYS

In the article the authors show the results of studies of the formation of a matrix of metal composite materials based on Nickel intermetallic, reinforced with single-crystal aluminum oxide plates.

The article consists of four parts.

The introduction shows the need to create heat-resistant composite materials for use in gas turbine engines of the new generation. In the framework of the comprehensive directions 12 and polimetrica metal-matrix composite materials investigated the samples the microstructure of the metal composite material, carried out x-ray diffraction and microstructure analysis.

Materials and methods are described in detail. In this work, samples for research were obtained by the method of reaction impregnation. The matrix of the composite material was synthesized by impregnating the frame consisting of monocrystalline aluminum oxide plates with matrix-like nickel powder containing 10, 15 and 20% of the buffer material by melting aluminum.

Microstructure studies, x-ray phase analysis and microhardness determination were carried out to identify intermetallic phases. It was found that all samples have phases NiAl, Al3Ni, Al3Ni2, AlNi3. Free Ni is not detected, which indicates a complete reaction in the preparation of the composite material.

In the discussion and conclusion, the general conclusions of the research are given. It is established that with increasing content of buffer material decreases the amount of low-melting phases and the stoichiometry shifted in the direction of NiAl, which is confirmed by studies to determine the percentage of each phase in the volume of the matrix. It is also noted in the work that with an increase in the matrix of Nickel nanoparticles, the number of fusible p

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7.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-59-67
УДК 620.193.2:629.7.023
Kuznetsova V.A., Zheleznyak V.G., Silaeva A.A.
INFLUENCE OF MECHANICAL CHARACTERISTICS OF PRIMING COVERINGS ON STABILITY TO CYCLIC MECHANICAL LOADS OF SYSTEMS OF THE EROSION RESISTANT DISPERSE REINFORCED COATINGS

To develope the system of coverings intended for protection of products of aviation engineering from erosive damages in addition to directly erosion resistant disperse reinforced covering special attention is necessary to be given to properties of priming coverings as durability of operation of coating system is provided by adhesion interaction of first coat with material of substrate and subsequent coat.

Results of research of influence of mechanical characteristics of different priming coverings on resistance of systems of paint coatings to erosive influence and cyclic deformation tests are given in this work. As objects of research the serial first coats which are widely applied at coloring of aviation engineering – EP-0214, VG-28, EP-076, EP-0215, have been chosen; as the erosion resistant disperse reinforced covering the paint and varnish material on the basis of the epoxy oligomer modified by rubber than cured by organic silicon ammine and filamentary crystals of ZnO as disperse reinforcing filler has been chosen.

Mechanical characteristics have been defined (εр, σр) for free films of first coats. It was revealed that the primer EP-0214 is the most elastic. Investigated the adhesive durability and erosion resistance of systems of coverings on the basis of the specified materials. Results have shown that the greatest adhesive durability and erosion resistance of coating systems with the most elastic first coat EP-0214 is possess. Data analisis received at research of adhesive durability of coating systems with different first coats after cyclic bending tests, have revealed considerable superiority of systems of coverings with more elastic first coats over systems of coverings with more rigid first coats.

We assumed that mechanical properties of priming coverings influence operati

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8.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-68-76
УДК 667.64
Kuznetsova V.A., Zheleznyak V.G., Baranova N.V., Lebedeva N.N.
INFLUENCE OF HARDENER ОS-17 ON EXPLOITING PROPERTIES OF THE VARNISH COVERING UR-231

For protection of functional assemblies of radio-electronic equipment and printed circuit boards use paint and varnish materials. Coatings on the basis of such materials have to show the increased values of moisture resistance and certain electric insulation characteristics. Among such materials in Russia the greatest distribution have polyurethane coverings, in particular epoxy urethane varnish UR-231.

This varnish represents two-packaging paint cured by polyisocyanate hardener with trademark diethylene glycol urethane (DGU). One of shortcomings of this varnish is the long time of forming of covering after drawing – 19 hours at 65°C Decrease in time of drying of paint coatings is desirable as leads to considerable power saving, manpower and to reduction of technological process. It is possible to solve this technological problem using hardener with the increased functionality, without changing thus basis material. In this work possibility of application as hardener interaction product toluiolendiisocyanate with OS-17 trimethylolpropane is considered. Exploiting properties of paint polymer coating can be defined substantially by properties and hardener structure, moreover at increase in functionality of hardener, degree of cross-linking of polymer in coating can increase that can be reflected in the  physicomechanical properties of coating. Authors have carried out tests of operational properties of coverings and have carried out the comparative analysis of the received results.

Authors assumed reduction of technological stage of drying of varnish UR-231 with use OS-17. For research of process of drying of coverings determined the hardness of varnish and have established that the maximum hardness of varnish with hardener OS-17 is reached in 4 days while for varnish with DGU hardener in 5 days, it has thus appeared that varnish hardness with OS-17&

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9.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-77-98
УДК 629.7.023:66.017
Solovyanchik L.V., Kondrashov S.V., Nagornaya V.S., Melnikov A.A.
FEATURE OF RECEIPT ANTI-ICING COATING (review)

Recently, an intense research to create new functional materials is carried out. In aircraft constructing area, special attention is paid to anti-icing surfaces.

It is known that icing is a non-stationary process that occurs when an aircraft enters the clouds with tiny drops of supercooled water that rapidly crystallizes on the surface of the aircraft. Currently used de-icing methods require additional energy and increase in the weight characteristics of the aircrat by 1–1,5%. Therefore, anti-icing coatings are extremely promising.

In a number of cases, superhydrophobic coatings are used  as passive anti-icing coatings. Such coatings possess high mobility of liquid droplets on the surface and low ice adhesion. Main disadvantages of superhydrophobic coatings are an increase of wettability with decreasing temperature and humidity and low icing-deicing cycles’ and operational sustainability.

Low ice adhesion and high icing resistance and hydrophobic properties may be obtained by the impregnation of a structured surface with a layer of a lubricant that forms a thin smooth film repelling water («SLIP»). The disadvantage of this approach is the need for continuous renewal of the lubricant layer during operation.

Smooth coatings based on elastomeric compositions also provide anti-icing properties. Ice adhesion in such coatings is influenced not only by low surface energy provided by a structure of a polymer matrix, but also by elastic properties of the compositions that change the ice removal mechanism from the surface of the coating. The main disadvantage of such coatings is their low abrasion resistance.

A promising approach to produce anti-icing coatings is the use of organogels and surfaces that contain a layer of water that do

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10.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-99-109
УДК 620.171.2
Ilichev A.V., Gubin A.M., Akmeev A.R., Ivanov N.V.
DEFINITION OF AREA OF THE MAXIMUM SHEAR DEFORMATIONS FOR CFRP SAMPLES ON IOSIPESCU METHOD, WITH USE OF OPTICAL SYSTEM OF MEASUREMENTS

Within FTsP «Development of civil aviation engineering of Russia for 2002-2010 and for the period till 2015» the PCM (Polymeric Composite Materials) complex on the basis of epoxy molten binding is developed for application in design of motor-engine nacelle of aviation gas turbine engines.

There are become widely used structural composite materials in the elements of the nacelles of modern aircraft engines. But they have strongly marked properties anisotropy of the orientation-dependent reinforcements. In the paper, the question of the change character of localization area of maximum shear strain during testing of samples of carbon-fiber plastic in four planes according to standard ASTM D5379 (GOST R 56799) was considered. In the frames of this research two brands of structural carbon fiber based on carbon equivalent fabric and carbon rowing were considered.

Measurements of strain field were made with optical DIC (Digital Image Correlation) system Vic 3D. Also the question of influence of measured area length on veracity was considered as well for DIC meters and for pasted strain gauges. During the testing process specimens were brought up to maximum load corresponds to fault or strain limit achievement. The strain field at the maximum stress, preceded by the failure or attainment of a 5% shear strain is shown in the figure 1. The strain fields are in the tangential stress plane xy, with respect to the optical view of the sample. So, based on the results of the research, a local zone of maximal shear strains, caused by a complex stress, has been defined. It was found that the localization area of shear strain has a different character depending on the direction of the plane subjected to the shear to reinforcement plane of the material.

The values obtained were compared with the results of strain gauges on the&

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11.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-110-118
УДК 621.742
Yashina S.A., Klyukvina T.D.
THE STUDY OF THE MECHANISM OF SELF-HARDENING MIXTURES FRIABILITY (review)

Sand casting is the most widely used process to manufacture castings. It is used to produce different configuration castings from various alloys. But castings producing with sand casting have low accuracy and surface finish.

At present no-bake processes become more used. These processes have following advantages:

– flexibility to produce different configuration castings from various alloy;

– simplicity to regulate properties of sand molds and cores;

– availability of materials;

– possibility to use simple molding equipment;

– simplicity of knocking out castings.

The mixture consists of sand, binder and catalytic agent.

Resin is the most widely used binder in no-bake processes.

In the article resin of acidic, alkaline molding processes and resins with urethane bonding are analyzed. Advantages, disadvantages and features of work with these resins are given. Understanding of relation between composition and sand mold properties is important for successful work with self-hardening mixtures.

One of the most significant properties of molding mixtures: the friability is discussed in this article. Friability is the tendency of the surface layer of mold to fracture during abrasion. It is found to depend on composition, moisture, water absorption and vitality.

Friability is found to have to be lower than 0,1–0,2%.

The purpose of further investigation is searching for optimal mixture composition to using this composition in Russian foundries.

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12.
dx.doi.org/ 10.18577/2307-6046-2018-0-6-119-127
УДК 620.1:669.715
Morozova L.V., Grigorenko V.B.
RESEARCH OF CAUSES OF DESTRUCTION OF THE IMPELLER AND FAN WHEEL FROM ALLOY AK4-1

The article presents the results of a complex study of two cases of operational destruction of parts of a complex configuration of AK4-1 alloy (impeller and fan wheel). Macro- and microstructures were evaluated to determine the causes of failure by optical and electron microscopy, chemical analysis and mechanical testing, and the chemical composition, mechanical properties, and the nature of fracture of the parts were studied. It is established that the chemical composition of the impeller material and the fan wheel meets the requirements of regulatory documentation, defects of metallurgical origin, both in the metal parts and in the fractures are absent. When analyzing the macrostructure of the impeller, a structural heterogeneity is revealed in the form of heterogeneity, while in the fan wheel the macrostructure is relatively homogeneous, the grain size does not differ significantly. Analysis of the microstructure of both parts revealed no defects and traces of burns. The microstructure of the parts corresponds to the AK4-1 alloy in the quenched and aged state. The mechanical properties of the samples made from the fan wheel meet the requirements of the regulatory documentation, and in the samples cut from the coarse-grained region of the impeller, the mechanical properties are reduced and their compliance with the requirements of the specification at the lower limit. The hub breaks of the fan impeller and the fan wheel blades have a fatigue structure. Fatigue destruction of the impeller developed from a surface on which rough risks from machining are located. The presence of zones with a relief of overload fatigue indicates the development of a crack under the action of high cyclic loads. The destruction of the fan wheel blade occurred at the transition point to the hub, from the side of the trough. Destruction occurred under the action of cyclic loading and has a multi-focal, fatigue character. Foci of failure are associated with&

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