Archive - Электронный научный журнал "ТРУДЫ ВИАМ"



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1. 10.18577/2307-6046-2018-0-12-3-13
УДК 66.017
Aslanyan I.R., Rassokhina L.I., Ospennikova O.G.

The modern model compositions for investment casting represent the complex the mixes, possessing diverse properties that is caused by availability of the big numbers of initial components in their structure. In this regard identification of the general patterns of change of technical characteristics on model compositions in dependences on quantitative structure even basic components, and, therefore, and development of modern model compositions, the models of casting intended for manufacturing of responsible details, represents quite complex challenge quantitative and qualitative choice of initial components.

In this work this task decided by means of mathematical methods of planning of experiment that has allowed to establish the influence of basic components (mutual solvent, the polymer, strengthening component and filler) on some technological properties of model compositions.

Use of the full factor experiment when developing model compositions with the set technological by properties has allowed to determine the extent of influence of quantitative factors (the main components which are a part of model compositions) on dropping temperature and heat stability of model structures. As a result of the carried out experiments it is established that on dropping temperature the main influence renders strengthening component and polymer, and on heat stability temperature the main influence renders polymer and mutual solvent. With increase quantities of strengthening component and polymer in model compositions of its dropping temperature will decrease. Temperature of heat stability of the model compositions will decrease with increase in amount of polymer and mutual solvent in its structure. Thus maintenance of filler, as separate factor, does not make considerable impact on dropping temperature and heat stability of model compositions, but infl

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2. 10.18577/2307-6046-2018-0-12-14-24
УДК 669.293
Kuzmina N.A., Svetlov I.L., Zaysev D.V., Zavodov A.V.

The interface in natural Nb-Si composites is analyzed for three structural modifications of Nb5Si3.On the basis of the crystal-chemical analysis of the phase conjugation surfaces, using the concept of the lattice of matching nodes, the value of the discrepancy in the interatomic distance of the mating planes is determined and the conclusion is made about the mechanisms of compensation of the lattice mismatch, the degree of deformation of the crystal lattices and the possibility of diffusion processes on the interface for Nb–Si composites with different modifications of the silicide.

Based on the crystal-chemical analysis of the interfacial boundary in the composite Nb–α-Nb5Si3 using the concept of a lattice of coincident nodes, the value of the discrepancy between the interatomic distances in the mating planes is determined: it is 3.8% in a series of atoms perpendicular to the direction of growth, and an order of magnitude less – 0.4% - along the direction of growth. At small (less than 10%) mismatch values, compensation at the interface can occur due to elastic deformations of the mating re-grids, without defects in the crystal structure.

In the composite Nb–β-Nb5Si3 based on the difference of average interatomic distances in the matrix of Nb and the silicide β-Nb5Si3, the value of the dimensional mismatch of the adjacent lattices is at 7.8%. For interphase boundaries with a mismatch of less than 10%, compensation can be achieved by elastic deformation and the formation of an average lattice with a period of ~3Å without defects in the crystal structure.

Crystallochemical analysis of the planes of the interfa

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3. 10.18577/2307-6046-2018-0-12-25-36
УДК 669.017.165
Evgenov A.G., Bazyleva O.A., Golovlev N.A., Zaysev D.V.

This paper is a work of investigating the structural features of VKNA-type Ni3Al-based alloys, made by selective laser melting (SLM) in several conditions: directly after synthesis, thermal and gas-static treated. The main features grain structure formation are shown depending on the content of carbon in the alloys. In previous scientific research it was established that crystallization for VIN5 and VKNA-1VR alloys obey the normal crystallization law. Right after the melting, matrix for VIN5 and VKNA-1VR is a g-solid solute, and dispersed pieces of the γ′-phase are uniformly distributed in the grain volume. Type VKNA25 (VKNA 25R) alloy has another crystallization mechanism: the distribution of  alloying elements changes. γ′-phase is now the matrix after synthesis.

The carbon influence and the amount of carbides on the recrystallization process and the formation of grains in the synthesized metal in the process of HIP are considered. It is shown that VKNA25 ( HIP) has practically equi-axed grain formation. Some grains contain twins, as the cause of the formation of which can be both the recrystallization process and micro strain in the process of comprehensive compression at the HIP. VKNA25 (R) has the preferred orientation of the elongated grains in the [001] direction. VIN5 and VKNA25 alloys after the HIP have the γ′-phase particles with a predominantly cubic morphology. VKNA25 (R) has irregular shapes of the γ′-phase parts.

The properties of the short-term strength of intermetallic alloys are determined in comparison with each other in different conditions (even casted). The values of the long-term strength of the synthesized materials right after melting and subsequent HIP are determined. It is shown that the long-term st

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4. 10.18577/2307-6046-2018-0-12-37-45
УДК 669.295
Alexeev E.B., Nochovnaya N.A., Novak A.V., Panin P.V.
WROUGHT INTERMETALLIC TITANIUM ORTHO ALLOY DOPED WITH YTTRIUM. Part 2. Research on heat treatment effect on rolled slab microstructure and mechanical properties

Microstructure of a rolled 35 mm thickness plate (slab) from wrought intermetallic titanium ortho alloy doped with yttrium has been shown, the microstructure being characterized by primary b-grains stretched along rolling direction, and fine precipitations of ordered intermetallic a2 phase located both inside the grains and in grain boundaries.

The influence of two-stage heat treatment (in particular the 1st stage heating temperature) on microstructure and mechanical properties of the rolled plate has been investigated. The first stage heating temperature varied in the range from 890°С to 1010°С with the step of 30°С. All other parameters (process duration, heating and cooling rates) of the two-stage heat treatment remained unchanged. Aging of the samples was performed in a two-phase (О+b/В2)-area with a subsequent cooling in a furnace at a rate of 150°C per hour.

According to the microstructure analysis results, it was observed that the samples from a rolled plate after being subjected to the selected heat treatment modes possess microstructure which is characterized by plate-like O phase particles and globular a2 phase particles in the b/B2 phase matrix. The complete transformation of a2 phase into the O phase does not occur due to the lack of diffusion mobility of atoms upon the selected aging temperature and duration.

It has been shown that the 1st stage heating temperature increase from 920°C to 980°C leads to the dissolution of large primary O phase plates and to the growth of fine secondary lamellar O phase plate-like precipitated within b-grains.

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5. 10.18577/2307-6046-2018-0-12-46-53
УДК 678.072
Zharinov M.A., Shimkin A.A., Akhmadieva K.R., Zelenina I.V.

Today among most widely used polymer resins for high-temperature composites are polyimide resins. Despite the significant successes achieved over recent decades in the field of optimization of polymerization type polyimide resin compositions, the problems of improving the processability, as well as increasing the working temperature and strength values remain urgent pressing.

The objects of the research are solvent-free polymerization type polyimide resin VS-51 (TU 1-595-12-1682-2017) developed in FSUE “VIAM” and carbon reinforced plastic. Selected monomers and synthetic conditions allowed us to achieve near solvent-free imide-forming mixture of components. The use of ethyl alcohol as a component makes it possible to significantly reduce the toxicity of polyimide resin VS-51. It should also be noted that due to the increased concentration of the  resin, the shelf life at -10 °C increases to at least 6 months.

Properties of the cured resin samples are investigated by thermal analysis. The glass transition temperature is 363 °C, the onset temperature of intensive thermal-oxidative degradation is 514 °C, and the mass loss at 500 °C is 3.0%. The heat resistance of cured resin is at the level of foreign and domestic analogues. Samples of carbon reinforced plastic based on the VTkU-2.200 carbon fabric were manufactured and investigated. Samples of carbon reinforced plastic are characterized by the following values of physical parameters: density 1.575-1.592 g/cm3; binder content 36-39%, porosity 0.4-0.6%.

The heat resistance of the obtained samples of carbon reinforced plastic was evaluated using DMA method. The glass transition temperature was 377 ° C, the temperature of the peak of the tangent of the angle of mechanical loss – 409 ° C.

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6. 10.18577/2307-6046-2018-0-12-54-61
УДК 678.84
Evdokimov S.A., Shchegoleva N.E., Sorokin O.Ju.

Increasing demand for powerful gas turbine and propulsion engines leads to harsher operational conditions (i.e., higher temperature, speed, more tension, aggressive environments, etc.) which in turn require complex processing decisions. Increased efficiency of aircraft engines has been achieved by new design scheme, development of advanced materials and technologies.

The use of ceramic thermal barrier coatings enabled to increase the temperature in hot areas of gas turbines to the maximum value of higher than 1500 °C thus resulting in superior engine performance and efficiency. Although ceramic matrix composites (CMCs) are still prospective materials for the use in gas turbines, their implementation is around the corner due to their improved toughness compared to monolithic ceramics, higher temperature and lower density compared to superalloys.

CMCs are likely to be envisaged for middle and large-sized gas turbine engines as structural material for simple-shaped and thin components like burner linings, sealings, shrouds, etc.

This article highlights the studies on ceramic materials with the «self-healing» effect. It was shown that the use of CMCs with a «self-healing» ability enables elimination of small defects originating during the engine work, thus there is no necessity for landing, emergency engine stops, repairs, etc. In the beginning «self-healing» effect took around 1000 hours, but then researchers shortened the time to a minute at 1000oC by adding a small amount of Mn which in their understanding helps to promote such an ability.

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7. 10.18577/2307-6046-2018-0-12-62-70
УДК 620.1:667.621
Petrova A.P., Mukhametov R.R., Shishimirov M.V., Pavlyuk B.Ph., Starostina I.V.

By production of PKM use binding and the fibrous filler, thus the binding carries out number of functions: will define way of receiving composite material and its such properties, as durability, chemical resistance, warm and moisture resistance, climatic firmness, technological conditions of processing, etc.

In this regard it is important to know properties binding and to provide stability in the course of receiving. Therefore it is necessary to carry out control of the main properties  binding both at receiving stage, and in the course of processing in PKM to provide implementation of the guaranteed requirements for their properties.

In article properties binding which are control for carrying out target and incoming inspection thermosetting polymeric binding, and also at stage of tests binding with reference to technology of their processing and receiving PKM on their basis are considered.

At the first stage – receiving binding – important parameters are appearance, the maintenance of flying products, viability, viscosity, gelation time, density. As a rule, these parameters are used at carrying out target and incoming inspection.

At stage of receiving PKM important parameters binding are rheological properties and the curing mode which observance provides obtaining necessary physicomechanical characteristics otverzhdenny binding, thermal effects of transients.

As a part of  PKM important parameters otverzhdenny binding are glass transition temperature, tensile strength, compression, bend, relative lengthening, impact strength, adhesion binding to fibrous filler.

For definition of the resource characteristics necessary for establishment

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8. 10.18577/2307-6046-2018-0-12-71-78
УДК 678.747.2
Timoshkov P.N., Goncharov V.A., Usacheva M.N., Khrulkov A.V.

Abstract of the article "The effect of gaps and overlaps on the mechanical properties of polymer composite materials (review)."

This article discusses the effect of such defects in polymer composite materials as gaps and overlaps, their effect on the strength and rigidity of the material being manufactured.

As is known, the use of polymer composite materials in industry is currently increasing. One of the methods for obtaining parts from composite materials is the automated layout of narrow bands - AFP and the automated layout of wide bands - AFP. Automation is of great importance for the industry, as productivity increases, costs are reduced, waste is reduced. Manual layout can not meet the needs of a developing industry.

However, in the production of complex structures, defects can form - gaps and overlaps, parallel to the direction of the fiber. These defects can reduce the physical and mechanical properties of the material, change the local geometry and microstructure.

Recently, AFP and ATL have been modernized through mathematical modeling, but small gaps and overlaps are still present in the structure of the material and cannot be removed, since these defects are an integral part of the material layout. Gaps and defects of no more than 1.5 - 2 mm in size are allowed.

The results of various experiments showed that the shear strength readings decrease by an average of 5–15%, compressive strength by 12–20%, flexural strength by 12%, and with a combination of several defects, compressive strength can be reduced by 55% .

Since in the manufacture of complex parts it is impossible to remove small gaps and overlaps, it is necessary to reduce their nu

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9. 10.18577/2307-6046-2018-0-12-79-87
УДК 669.017
Morgunov R.B., Piskorsky V.P., Valeev R.A., Korolev D.V.

Many works were devoted to the influence of the magnetic field of 0.05 - 30 T induction and the duration of exposure in the magnetic field from 1 µs to several days on the mechanical properties of polymers, ion crystals, semiconductors, transition metals, fullerites, technological alloys. A brief analysis of the results in the study of magnetoplastic effects (the phenomena of changes in the plasticity and strength of metals under the action of a magnetic field) was done. 

The classification of known and physically justified effects on the basis of thermodynamic analysis of the energy is reported for the systems and the relaxation time of changes induced by the field. Controversial experimental results and their interpretations are discussed. Unified physical mechanisms controlling magnetoplasticity stimulated discussion of magnetoplastic effects simultaneously in nonmetallic solids, where the magnetic field also change structurally sensitive properties.

Most of the magnetoplastic effects, regardless of the type of material, obey a simple rule: transition time decreases with the growth of the magnetic field and the energy transmitted to the crystal lattice. Magnetoplastic effects which, obey this law can be called as "power" effects, i.e. those, which has a value of the magnetic force on the structural elements of the crystal or defects. Another part is characterized by more exotic mechanisms of influence of the field, not limited by the transfer of energy necessary for overcoming potential barriers. It is shown, that the effect of the magnetic field on the subsystem of structural defects is irreversible in many cases, while there are completely irreversible magneto plastic effects. In this case, the system does not return to its original free energy state even if its plastic properties seem to be restored.

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10. 10.18577/2307-6046-2018-0-12-88-96
УДК 678.026
Mukhametov R.R., Petrova A.P., Ponomarenko S.A.

The creation and development of new polymer composites requires continuous improvement of their physicomechanical and performance characteristics. PCMs breakdown begins from their surface often and it is important to provide its solidity and water repellent properties, including for improvement of performance characteristics of materials.

In the aviation industry, hydrophobic compounds are mainly applied at present to tooling processing at molding processes of polymer binders to prevent their adhesion.

Compounds based on organosilicon monomers and oligomers are the most widely used due to their efficiency and availability. One of the essential disadvantages of the use of such compositions is the need for curing to prevent their transfer to material moldable. Therefore, it is important to research the influence of cold curing catalysts on coatings properties and choose optimal ones.

In this work, the anti-adhesive characteristics of several organosilicon compounds – K-21 anti-adhesive lubricant, 136-157M water repellent liquid and GK-10 polymethylphenylsiloxane with hydride groups – were estimated and compared. Coatings were prepared from a solution in hexane by dipping. The best coating was chosen by adhesive strength of materials cured glued together by polyurethane glue PU-2. The completeness of curing of the anti-adhesive coatings was also estimated according to adhesive strength of materials cured before and after extraction with hexane in a Soxhlet device.

The work shows the effective use of catalysts 230-15 and AGM-9 and their optimal content is selected, the optimal composition and concentration of the anti-adhesive coating, as well as the curing mode to achieve the required characterist

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11. 10.18577/2307-6046-2018-0-12-97-106
УДК 669.295
Ospennikova O.G., Naprienko S.A., Lukinа E.A.

In the course of the work, the causes of cracks formation on a large-size item (compressor disk) of VT8 alloy, working as a part of GTU, are investigated. Visual inspection of the disc was carried out. At the rear end of the disk hub there are two cracks that bend around the end of the hub in a perpendicular direction and have an outlet to the inner and outer surfaces of the disk. On the facet, close to a development of cracks are observed in dark areas of the surface. Inspection of the disk surface and microstructural studies have shown that the item was exposed to temperatures above 400°C for a long time. Near the chamfer, the thinning of some parts of the silver coating of the inner surface of the disk hub was revealed. It is most likely that there was mechanical abrasion of the coating in this area. Near the chamfer, the thinning of some parts of the silver coating of the inner surface of the disk hub was revealed. It is most likely that there was mechanical abrasion of the coating in this area.

The study of the fracture surface revealed brittle facets on the fracture and a large number of branching secondary cracks. Multiple cracking found on the microsection made across the failure surface. The material composition of the dark areas on the surface of the chamfer includes silver, oxygen and chlorine.

Samples of the alloy ВТ8 were tested in static loading in a 2% HCl solution according to STO 1-595-30-468-2015. It is shown that the type of the fracture surface of the experimental and operational samples is identical. The results of studies indicate that the development of cracks occurred on the mechanism of stress corrosion cracking in the presence of chlorine ions. Thermodynamic analysis is carried out. It is shown that the reaction of the interaction of silver with chlorine and hydrochloric acid occurs at temperatures of 150-2000&

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12. 10.18577/2307-6046-2018-0-12-107-120
УДК 669.245
Dvoretskov R.M., Baranovskaya V.B., Mazalov I.S., Karachevtsev F.N.

To improve the accuracy of quantitative evaluation of the phase composition of high-alloyed alloys, electrolytic phase extraction is used, which includes anodic dissolution of the alloy sample in a specially selected electrolyte for passivation of the corresponding components, study of the phase and chemical composition of the passivated anodic residue and using the results of these studies for calculating the mass fraction of phases in the sample alloy and distribution of elements between phases. A scheme has been proposed for studying the quantitative phase composition of nickel alloys using electrolytic extraction of phases in which the chemical composition of the anodic residue is determined by the difference in the concentrations of elements in the alloy and in the electrolyte after the extraction. To determine the elements dissolved in the electrolyte, the method of atomic emission spectrometry with inductively coupled plasma was used. The model solutions were used to investigate the interfering effects of the components of five electrolytes in the inductively coupled plasma atomic emission analysis of electrolytes after electrolytic extraction of the phases of nickel alloys. In order to minimize the influence of electrolyte components on the analytical signal of the elements being detected, it is recommended to electrolytically dissolve samples of nickel alloys to a mass of not less than 0.25 g per 250 ml of electrolyte, so that the electrolyte can be diluted. Methods for compensating disturbing influences are chosen - using solutions of standard samples of nickel alloys and internal standardization. An internal standard line Indium 230.606 nm is selected. The suitability of the presented research scheme for evaluation of the quantitative phase composition of samples of ZhS6K and VZh159 alloys using electrolytic extraction and inductively coupled plasma atomic emission analysis of the electrolytes was carried out. A compari

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