In this article the inspection of technological characteristics in Si content brazing alloys: VPr27 and VPr50 in a cast form and a powder made by gas dispersion was carried out. . Structure and a phase composition of brazing alloy characteristics such as spreading area and melting uniformity were researched.

The reasons of unsatisfactory results of VPr27 spreading area tests are presence of large silicides of (WMo)₅Si₃ type in structure, that interference to a normal brazing alloy spreading. More over in brazing alloys with satisfactory spreading characteristic were also founded smaller particles of silicide types Me₅Si₃, that shows the general doping system instability. The factor that determines dimensional parameters of particles were not founded consequently as a spreading characteristic of brazing alloy.

In VPr50 brazing alloy, made with a technical purity Cr – «X99H4», were discovered the presence of phases based on Cr–Mo with cubic based or similar morphology cell with an accurate facet that conflict with formation in double diagramme Cr-Mo. The established phase chemical compounds are not allowed to refer it to one of the known type. In brazing alloy VPr50 that made from high purity materials in a laboratory arc furnace, revealed a Cr and Mo segregations with variable structure, that can be easily revealed by the composite contrast. Formation of Cr–Mo based phases revealed in metal after vacuum induction meting method, probably could be connected with such segregations and destabilized doping system by impurity intercalation, such as the oxygen, that can be imported during the melting with a technical purity Cr – «X99H4». As a result it forms a connections of various (at least two) lineage ratios based on Cr–Mo, that are not common for casting materials.

The object of development is a new heat-resistant steel for bearings of aviation GTE gearboxes of airplanes and helicopters.

The aim of the work is to develop a new heat-resistant bearing steel, which is not inferior in performance characteristics to the foreign analogue M50 and is superior in domestic carbide uniformity and workability during hot plastic deformation to EI347 steel.

The paper discusses the principles of doping new heat-resistant bearing steel. The effect of the main carbide-forming elements Cr, Mo, W, V, providing the secondary hardness of steel during tempering, is shown. The influence of non-carbide-forming elements (Ni, Mn and Si) on the processes of hardening and processability of steel has been determined. An alloying system was selected that improves the processability of steel under plastic deformation by reducing carbide heterogeneity and providing heat resistance to new steel up to 500°C (hardness 61–63 HRC).

The effect of non-metallic inclusions in steel on the reduction of bearing performance is analyzed. As a result, the use of vacuum technologies in the smelting of new heat-resistant bearing steel achieved a significant reduction in metal contamination by non-metallic inclusions (up to 1 point according to State Standard 1778).

The carbide heterogeneity of rods of different sections of new steel for bearings is investigated. It is shown that with an increase in the diameter of rolled products, the carbide heterogeneity score increases, which is explained by a lower ingot reduction. Therefore, in addition to optimizing the composition of the bearing steel, one of the effective methods for reducing the carbide heterogeneity is the use of high weight ingots for the production of semi-finished products of bearing steel.

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Three-layer honeycomb panels, which are still used in the interiors of airplanes, developed in the 1980s by FSUE “VIAM”, consist of claddings made of glass fiber laminates based on FP-520, FPR-520, EP-2MK binders, etc. and honeycomb core polymersotoplast PSP-1, on the binder BFOS. All of these binders contain organophosphorus flame retardants Fosdiol A or Fospoliol II.

In recent years due to the restriction of production methylphosphonic acid dichloride, which is a raw material for the flame retardants Phospoliol II and Fosdiol A, has a problem with their production.

In the course of this work, the effect of 15 samples of organophosphorus flame retardants provided by the FSUE “GosNIIOKHT” on the physicochemical and technological indicators of the FP-520 binder and BFOS and materials based on them was investigated.

The obtained experimental batches of the FP-520 binder with new fire retardants are storage-stable transparent solutions of red-brown color without mechanical inclusions with a density from 1,123 to 1,132 g / cm3, kinematic viscosity from 73.9 to 184 mm2 / s, and non-volatile content 67.2 - 70.3%.

The effect of flame retardants on the physicomechanical properties of the resulting glass fiber textolite ST-520-15 based on the modified binder FP-520 was investigated.

Introduction of new fire retardants allows to obtain glass fiber laminate with strength characteristics comparable to those of ST-520-15 on FP-520 binder with Fosdiol A. For fire safety, samples of two-layer fiberglass ST-520-15 and a three-layer panel based on FP-520 containing new flame retardants AP-25 requirements are self-extinguishing and low smoke.

The properties of the samples of phenolic binder BFOS containing new&

The effect of resorcinol modifying additive on technological and thermo-mechanical properties of epoxy resin system based on tetra-functional resin and its mixtures with DER-330 epoxy bisphenol A resin was studied. The effect of resorcinol additives on viscosity, flexural strength, dry and wet glass transition temperature of epoxy resin system cured with asymmetric urea is shown. The effect of the amount of asymmetric urea on the thermo-mechanical properties of modified and unmodified epoxy resin systems was also determined.

Traditionally, epoxy resins occupy the leading positions in the field of high-performance thermosets. Characteristics of based on epoxy resins plastics have good performance, which is enough to solve most problems. However, often the heat resistance of epoxy binders is insufficient, so the development of polymers with improved characteristics remains relevant. Benzoxazines can be presented as the special type of aminobenzaldehyde resins. The strength of benzoxazinones system is comparable to epoxies, while the work temperature of benzoxazinones is at the level of work temperature of bismaleimides. This fact means that benzoxazines can provide high competitiveness to existing resins. The advantages of benzoxazine binders include: absence of volatile compounds during curing; excellent mechanical strength; high compressive strength and modulus of elasticity; low water absorption; almost zero volume shrinkage/expansion during curing; excellent resistance to chemically aggressive compounds and to the ultraviolet radiation; high glass transition temperature (Tg); high coke residue during decomposition; excellent fire safety performance; the possibility of copolymerization with other monomers.

Polymer benzoxazines are the class of polymers in the structure of which there are oxazine rings. Such compounds contain at least two oxazine groups and are able to harden (polymerize) under the influence of temperature to form a cross-linked spatial matrix. As a rule, high-molecular benzoxazines have difference in compares to low-molecular ones by better thermal and mechanical characteristics due to the formation of a more perfect polymer mesh with a greater degree of cross-linking. An important addition is the ability to process them as thermoplastics.

Oligometastasis could be allocated as a separate class that has the difference with monomers and polymers. From the point of vi

Sealing materials (sealants) are used in various areas of technology, largely ensuring the performance of structural elements and assemblies of airplanes, helicopters, space technology, fuel compartments and the caisson - tanks, watertight partitions, pipelines, chemical devices, etc. The article examines changes in the technical characteristics of sealants after they are kept in a free state in various climatic zones: temperate climate of the MSCI; temperate warm climate of the seaside zone GCCI, desert (Arizona), subtropical (Florida) climate of the USA and tropical climate (climatic stations of Vietnam). Sealants of various chemical structures were studied: VITEF 1B polysulphide sealants, TU 1-595-53-633–2001 and VGM-L, TU 1-595-28-934–2009 – siloxane sealant WIKSINT U-20-99, TU 1-595-53-614–2000 and fuel resistant fluorsiloxane VGF-2M sealant TU 1-595-28-1099–2009. The nature of aging of sealing materials after exposure to climatic factors is determined. According to the results of the conducted research, it was established that - the nature of changes in the properties of sealants after exposure in the climatic zone of the MSCI and GCCI is identical. The clinical picture of the aging of sealants after aging in the climatic zones of the United States of America is similar for materials of close chemical aging. After aging of sealing materials in the climatic zones of Vietnam, the aging of sealants has a complex characteristics. An increase in surface hardness up to 42% of the initial value is observed; tensile strength increases to 43% for VGM-L and decreases to 36% for VGF-2M; elongation at break for VITEF-1B is reduced by up to 70 %. Thus, all of the selected sealing materials showed significant deterioration in properties after aging in a tropical climate in an open area.

Of all the climatic zones studied in this work, the greatest degree of degradation of seali

Materials based on refractory metals (molybdenum, tungsten) are widely used in various fields of technology. However, the manufacture of blanks and products from them is not an easy task, since molybdenum and tungsten have high melting points, are easily oxidized in air, are low-plastic and hard-to-deform metals.

In this work, materials based on the Mo-W system obtained by powder metallurgy technology were investigated. To consolidate the powders, a promising method was chosen — electric-spark plasma sintering.

At the initial stage, the effect of mixing time in a ball mill on the homogeneity and properties of molybdenum-tungsten powder mixtures was investigated. To obtain a homogeneous molybdenum- tungsten powder mixture, the optimum mixing time of 10 hours was established using a drum mill. The selected mixing parameters (time and ball load) make it possible to destroy the agglomerates and to achieve good homogeneity of the powder mixture, without having a significant effect on the particle size distribution, bulk density.

Mechanical properties are directly dependent on the content of tungsten. Strength values increase with increasing sintering temperature. The fractures of the samples after mechanical tests were investigated and it was established that the material breaks down intercrystalline brittle, which is associated with the segregation of impurities along the grain boundaries. The analysis of the microstructure of materials was performed using optical and scanning electron microscopy. Energy dispersive microanalysis was used for the distribution of elements over the cross section of the samples also the chemical composition of nonmetallic inclusions and phases were determined.

Due to the diffusion of carbon from the graphite matrix into the material, the refining of the boun

The article is devoted to the peculiarities of the technical standard basis for polymer composite material test methods. The large-scale work of the Technical Committee TC 497 is noted, under the authority of this TC over 450 standards have been developed in recent years, of which about 350 have already been put into effect.

This work considers such a particularity as a variety of standards with similar names in a single type of test, which is a consequence of harmonization simultaneously with ISO and ASTM standards. Comparative tables with lists of standards for tensile and compression testing of elementary specimens with indication of the scope, as well as equivalent standards and their names are given.

Also in this work shows nuances that cause difficulties when non-specialists choosing a standard for testing due to that in addition to the name, the scope of application in standards are similar. In many standards bright line fades between composites and plastics and even adhesives. However, it is noted that such an approach is acceptable, but these particularity must be taken into account when working with standards.

The problem of designation of national standards is shown on an example of ISO 6721 series for dynamic mechanical testing. A table of correspondence between the ISO standards of this series and GOST R is given.

It also presents one of the actual problems – disagreement in designations of determinable indicators of the polymer composites, a comparative analysis of the designations of the same indicators according to various standards is given.

The particularities noted in the article do not affect the quality of the tests results, but refer to the ease of use the standards, search process, relation between standards, etc.

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The antifriction organoplastics Orgalon AF-1MR-260 and Orgalon AF-1MR-500 on the basis of reinforcing fillers, which are a combined fabric of two types of fibers - polyteh-rafluoroethylene and aramid fibers were developed and investigated. Aramid fibers play the role of a reinforcing component of a fabric filler, and polytetrafluoroethylene fibers give antifriction properties. The materials are intended to form a self-lubricating antifriction polymer coating on the metal surface of friction knots operating at high loads.

Organoplastics Orgalon AF-1MR are developed by analogy with serial materials Orgalon AF-1M, whose fabric filler contains polyimide and polytetrafluoroethylene fibers in its composition. The purpose of the development of new antifriction materials is to reduce their cost and increase the load capacity compared to the standard organoplastics Orgalon AF-1M.

It is shown that the use of aramid fibers instead of polyimide fibers in the reinforcing fabric allows reducing its cost by 30–40 %, increasing the strength properties by 30–50 %, and also improving the adhesive interaction of the antifriction coating with the metal. For organoplastics Orgalon AF-1MR the strength when exfoliate from structural steel is 25-30 % higher compared to organoplastics Orgalon AF-1M.

It has been established that the developed antifriction organoplastics Orgalon AF-1MR have a high load capacity - they resist pressure up to 250-300 MPa. The friction coefficient of organoplastics (with a contact pressure of 30 MPa and a speed of 0.2 m / s) is 0.10 in a friction pair with structural steel.

Thus, the developed antifriction materials are highly effective for use in the construction of high-loaded self-lubricating friction knots and can be used in many engineering areas, such as aircraft, engi

Identification of damage and defects in the fiber reinforced plastics (FRPs) today are an integral part when building on-board monitoring systems. The need for practical implementation of such systems is associated with the importance of estimating the actual load, which, as a rule, is very different from that planned when determining the resource of an aircraft.

One of the important stages in the identification of detected defects in FRP is their classification and division into groups, which will allow you to make the most complete picture of the types of defects and apply general approaches to analysis, prevention, development control and repair of detectable damage for groups of defects.

From the gradual shift and broadening of the peak in the spectrum of the FBG response, it can be concluded how the stress concentration in FRP, which varies with increasing applied load, affects the strength and redistribution of the applied force in the material.

One of the ways to identify damage and determine the direction of the applied external action is the method of scanning a FRP structure with Lamb waves of ultrasonic frequency. As a rule, for a clearer separation of asymmetric and symmetric Lamb wave modes, the FBG integration is carried out in such a way that the axes of the FBG and the source of propagation of Lamb waves are angled to each other.

Studies of methods for identifying defects and damage in FRP to select the optimal method or a combination of them to study the causes, nature and development of damage FRP are used to accumulate experimental statistical knowledge about the state of a structure from FRP. In turn, the use of such data in the design, testing and operation of structures will make it possible to implement new approaches to the operation of aircraft, building structures

Satisfactory adhesion of the metal layer (MS) and the ceramic layer (CL) was ensured by the formation of a thin (about 1 micron) bonding or «adhesive» layer of aluminum oxide at the metal-ceramic interface. To prevent spallation of TBC under conditions of intensive cyclic heating to operating temperatures at which significant thermal stresses occur at the metal-ceramics border due to the difference in thermal linear expansion coefficients (TCLE), the CS should preferably have a special column structure.

The splitting of a ceramic layer of a ceramic layer of a TBC with a columnar structure can occur in the following main cases:

- аs a result of the growth of the thickness of the oxide layer on the basis between the metal bonding coat (BC) and the ceramic thermal barrier coating (TBC). When the thickness is more than 10–15 microns, spalling of the CL BC occurs. This is the main mechanism of spallation of the CL of the TBC under normal operating conditions; The thickness of thermal growing oxide (TGO) grows continuously throughout the time the product develops a resource. Taking into account the fact that the increase in the thickness of the TGO is a result of a chemical reaction, the temperature has a significant influence on the rate of its flow. Thus, by the thickness of the TGO, one can indirectly judge the level of temperatures that acted on the boundary between the CL and BC.

– as a result of sintering the ceramic layer (ZrO₂+(7–8)Y₂O₃) with the full or partial transformation of the columnar structure into a monolithic during long-term (more 50 hours) increase in surface temperature above 1250 °C. Further, under cyclic temperature effects on the blade, spalling of the CL of the BC occurs as a result of the thermal stresses that occur;

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Studies of the formation of porosity at the boundary «of the ZhS26 heat-resistant alloy–a heat-resistant condensation-diffusion coating» – have been carried out. An ion-plasma heat-resistant condensation-diffusion coating of the NiCoCrAlY+AlNiY system (SDP-4+VSDP-16) with different thicknesses of the condensed layer made of SDP-4 alloy (19; 38 and 76 µm) with the same thickness of the layer of alloy VSDP-16 (17 µm). Part of the coated samples was subjected to vacuum thermal diffusion annealing according to standard technology.Investigations of samples in the initial state and samples after vacuum annealing were carried out, their microstructures were shown, and the results of micro X-ray analysis (MRCA) were given.It is shown that on samples of a heat-resistant alloy ZhS26 with a condensed coating SDP-4 with thicknesses of 19 and 38 μm in the vacuum annealing process at the boundary «of the heat-resistant alloy ZhS26–a heat-resistant condensation-diffusion coating» of the system SDP-4+VSDP-16 forms a pore chain. «On sample ZhS26 with a condensed coating SDP-4 76 μm thick, pores are not formed on the «alloy–coating» interface.