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The results of a 20-year-long longevity bench testing of nineteen full-size thermosyphons (TSs) made of steel 20 at a steam-water medium temperature of 240–265°C are presented. For the manufacture of TSs, various methods for processing the inner surface and different compositions of filling aqueous solutions have been used. The thermosyphons were periodically removed from the tests and cooled for monitoring the conditional relative vacuum $${{p}_{{{\text{vac}}}}} = 1 - {{{{p}_{0}}} \mathord{\left/ {\vphantom {{{{p}_{0}}} {{{p}_{{{\text{atm}}}}}}}} \right. \kern-0em} {{{p}_{{{\text{atm}}}}}}},$$ where $${{p}_{0}}$$ and $${{p}_{{{\text{atm}}}}}$$ are the absolute pressure in the steam-gas volume of the thermosyphon and the atmospheric pressure, respectively. The value of $${{p}_{0}}$$ was determined using a thermal method described in this paper, which does not require thermosyphon depressurization. After the last inspection of pvac, four TSs were removed from the tests. The solution contained therein was taken for the chemical analysis of its composition. For the inspection of the inner surface, samples were cut out of the pipes. For the samples of one thermosyphon, metallographic studies were performed to assess changes in the structure and mechanical properties of the pipe metal in the course of hydrogen diffusion through the pipe wall. It was revealed that 16 of 19 TSs exhibit a decrease in pvac less than 6% during the test period. A high performance was also obtained for TSs manufactured according to the economical technology reported in this paper. The oxygen-free environment inherent in the thermosyphons provide self-passivation of the thermosyphon internal surface with the formation of a protective layer of magnetite. This layer reduces the corrosion rate with releasing hydrogen up to the rate of hydrogen removal via diffusion through the wall of a carbon steel pipe. Retaining the initial vacuum, reducing the wall thickness of the thermosyphon less than by 0.1 mm, and the positive results of metallographic studies confirmed the potentialities of long-term thermosyphon operation with retaining high heat-transfer characteristics and with the absence of hydrogen influence on the structure and mechanical properties of the thermosyphon metal.

Experimental study results for thermal fatigue fracture of sand-glass specimens from a ZhS32 single-crystal alloy with different crystallographic orientations are presented over a wide range of maximum and minimum cycle temperature variations. Crystallographic, fractographic, and finite element data were used to identify crystallographic and noncrystallographic fracture modes of a single-crystal alloy. The noncrystallographic mode is realized at high maximum cycle temperatures and comparatively narrow temperature ranges. It is characterized by mode I crack growth. The crystallographic mode is realized at lower maximum temperatures and a wide range of cycle temperature variations. It is characterized by combined I–II mode crack growth in crystallographic plane {111}. The chart of fracture mechanisms in the maximum temperature-temperature range coordinates is proposed. The boundary between the regions permits of approximation, corresponding to the Arrhenius equation.

A large number of parametric methods were proposed to calculate the characteristics of the long-term strength of metals. All of them are based on the fact that temperature and time are mutually compensating factors in the processes of metal degradation at high temperature under the action of a constant stress. The analysis of the well-known Larson-Miller, Dorn-Shcherby, Menson-Haferd, Graham-Wallace, and Trunin parametric equations is performed. The widely used Larson-Miller parameter was subjected to a detailed analysis. The application of this parameter to the calculation of ultimate long-term strength for steels and alloys is substantiated provided that the laws of exponential dependence on temperature and power dependence on strength for the heat resistance are observed. It is established that the coefficient C in the Larson- Miller equation is a characteristic of the heat resistance and is different for each material. Therefore, the use of a universal constant C = 20 in parametric calculations, as well as an a priori presetting of numerical C values for each individual group of materials, is unacceptable. It is shown in what manner it is possible to determine an exact value of coefficient C for any material of interest as well as to obtain coefficient C depending on stress in case such a dependence is manifested. At present, the calculation of long-term strength characteristics can be performed to a sufficient accuracy using Larson-Miller’s parameter and its refinements described therein as well as on the condition that a linear law in logσ–Р dependence is observed and calculations in the interpolation range is performed. The use of the presented recommendations makes it possible to obtain a linear parametric logσ–Р dependence, which makes it possible to determine to a sufficient accuracy the values of ultimate long-term strength for different materials.

The structure and properties of carbon-containing single-crystal alloy ZhS32 and carbonless single-crystal alloys ZhS36, VZhM4 and VZhM5U are studied after 500 – 3000-h aging at 850 – 1100°C. The resistance to elastoplastic strain, creep and fatigue and the characteristics of long-term strength of the alloys are determined. It is shown that the expected values of long-term strength and creep resistance of the single-crystal alloys should be corrected with allowance for the changes in their initial structure after long-term operation.

The features of the integrated diagnostics of the discs of gas turbines of gas-compressor units using eddy-current and dye-penetrant testing are considered. The effectiveness of the detection of the crack-type defects in HPT and LPT discs under the first tooth of the fir-tree slots of the discs along the contact line of the teeth of the comb and blade butt are demonstrated. The calculations of the stress–strain state allowed the estimation of the occurrence of cracks in the fir-tree slots of discs, as well as the service life of discs up to crack formation at extraordinary operating temperatures. Integrated quality control by eddy-current and color capillary nondestructive testing provides reliable crack detection in details without serious costs for mechanical preparation of items for inspection along with a substantial reduction of the labor-intensiveness and depth of the inspection.

The lifecycle of modern industrial gas turbines can reach hundred thousand hours and usually the turbine blades need to be replaced. The use of super alloys and application of advanced coatings makes the cost of turbine lifecycle rather high. The methods for blade rejuvenation and life extension are based on the analysis of the main defects which can considerably reduce blade strength. The effect of long operation and typical defects in turbine blades has been studied in correlation with HCF. The decrease of blades HCF under the effect of operation has been considered as the result of influence of mechanical and thermal factors. The influence of FOD on the blade HCF strength is studied. Some random defects in turbine blades which resulted in HCF decreasing and blade failure are considered. The rejuvenation heat treatment for the blades of ZhS6K and EI893 and its positive effect on metal properties is demonstrated. The ultrasonic shot peening for operated blades have been considered. It is demonstrated that HCF strength of blades after shot peening is about 25–30% higher. Relaxation of compressing stresses in operation is shown as not essential. The remaining life of operated blades can be estimated using the correlation of endurance limit and run time.

We propose using the method of holographic microscopy to detect fine morphologic changes in living cells. An “LSM 510” laser confocal scanning microscope is modified to allow recording digital microholograms which can be used to reconstruct the amplitude and phase of the radiation transmitting through the sample. Measuring the phase increment of the object beam in cells and the intercellular space yields information on the optical length of the ray path in the cells (spatial dimensions and the refractive index), which in turn contains information on changes in the morphology and intracellular contents. Calcium activity is studied by means of fluorescent microscopy which makes it possible to detect minor variations in the intracellular concentration of calcium ions. By studying the dynamics of calcium oscillations and variations in the optical thickness, conclusions are made about the interrelation of functional and morphological variations, and comparative analysis of these variations is performed.

We present the concept of combining the holographic and localization fluorescent microscopy. The ways to optimize the optical schemes and image recording regimes in the process of combining such interferometric and statistical methods are developed, which makes it possible to study the dynamics of the internal cell structure with transverse and longitudinal superresolution.

The problem of continuous spin detonation in a supersonic flow in a flow-type annular combustor is considered in a two-dimensional unsteady formulation. The dynamics of the detonation wave in a hydrogen-oxygen mixture with isentropic and shock-wave compression of the flow in the input diffuser is studied. It is shown that the mass flow rate of the mixture through the combustor decreases as continuous spin detonation is formed, and a steady regime with a “detached” shock wave is observed at the entrance of the supersonic diffuser. For a contoured combustor, the limit from above is obtained for the Mach number of the incoming supersonic flow at which a continuous detonation regime is obtained.

A mathematical model of continuous spin detonation for hydrogen-oxygen and hydrogen-air mixtures is developed within the framework of a nonstationary gas-dynamic formulation. An OpenFOAM package is used to carry out numerical calculations in an annular cylindrical combustor in order to compare the main solution parameters with experimental data for geometric dimensions of combustors 40 mm and 306 mm in diameter corresponding to the experiments for hydrogen-oxygen and hydrogen-air mixtures. Regimes with a single continuously rotating transversal detonation wave are obtained for given fuel mixtures. It is shown that the solution significantly depends on the coordinate along the radius. The results for the hydrogen-oxygen mixture are in good agreement with an experiment in terms of a wave velocity and satisfactory agreement relative to a front height and the number of waves (a 1.5- to 2-fold difference). The results for the hydrogen-air mixture are in satisfactory agreement with an experiment for the wave velocity and front height and significantly differ from it on a minimal flow rate of the mixture, in which the existence of continuous spin detonation is possible in the combustor.

Results from studies of factors due to which fatigue damage is inflicted to the turbine and compressor blades of stationary gas turbine units operating at the compressor stations installed on gas mains of Russia are considered.

The methods and results of the technical state inspection of gas pipelines in the Far North environment are considered. The stress-strain state calculations for gas pipelines in operation as well as metallographic and strength investigations of metal after operation have been performed.

The article presents the results of the analysis of operation of working blades made of cast nickel alloys applied in gas turbines for power. Russian alloys having equiaxial crystallization, i.e., TsNK-7, ChS-104, ZMI-3U, ChS-70U, ChS-88U, ZhS6K, and one foreign alloy IN738LC (for comparison) are considered.

Results from thermocyclic tests of nickel- and cobalt-based alloys used to manufacture blades for modern gas turbines are presented.

Results from studies on analyzing the state of materials and protective coatings of gas turbine blade systems subjected to the sulfide-oxide corrosion are presented, and factors causing its occurrence are described. Data obtained from studies on analyzing the effect of doping on the resistance of nickel alloys to corrosion are given, as well as data obtained from studies of the corrosion longevity of thermo barrier coatings.

We present the results obtained from a comprehensive study of the plasma metalloceramic coating applied on the external surfaces and diffusion coating applied on the internal surfaces of rotor blades and guide vanes used in stages 1–3 of a GTE-65 gas turbine unit.

Results obtained from exposure of nickel-based heat-resistant alloys to thermal fatigue tests carried out for several years are presented. A methodology of carrying out tests in vacuum is used, which makes it possible to observe incipience of microcracks and their propagation rate. Results obtained from a calculation of sample strain conditions are analyzed.

Specific features of thermal fatigue fracture of a monocrystalline alloy used in manufacturing of rotor blades of gas-turbine units are investigated. The dependences of the number of cycles to failure on the crystallographic orientation of the material, maximum temperature in a cycle, temperature range, and stress concentration are established. The effects of the pores and processes of recrystallization on the degree of thermal fatigue damage are analyzed.

The special features of diagnostics of turbine discs of ΓTK-10-4 gas compressor units tested by the dye penetrant flaw detection method are considered. It is shown that disc blades must be dismantled and carefully mechanically cleaned, the spots in discs where such flaws as cracks are generated most often being analyzed, thereby reducing the searching and detection time.

The mechanical properties of LPT moving blades of the 4th and 5th stages of GT-6-750 turbine produced from 12% chromium steel EP428 (20Kh12VNMF) are studied after serving for 100,856 h. The microstructure of the steel is studied by methods of light metallography and analytical electron microscopy with the use of EDX and EELS spectrometers. The phase composition of the metal of moving blades and the chemical composition of the Me23C6, Me2(C, N), and Me(C, N) phases after long-term operation at 350–500°C are determined. The phase and structural transformations occurring in the steel under such conditions are investigated.

Physicochemical phase analysis is used to investigate carbide phases in a high-temperature nickelbased alloy ZhS32 after the alloy has been subjected to various heat treatments and aging regimes within a temperature range of 850–1250°C. The MC, M23C6, and M6C carbide phases have been identified.

When defining the stress-strain state (SSS) and evaluating safety factors for turbomashinery components operating at high temperatures under creep conditions, deformation and fracture characteristics obtained during tests of as-heat-treated materials are usually used. At the same time, if the change in material properties during long - term service is taken into account, then the SSS of companents and, consequently, the real safety factors can significantly differ from design values which have been calculated without accounting for these changes. In this report the changes in material structure and deformation characteristics, stress-rupture and creep-rupture properties, and thermal fatigue for a number of materials of different types (perlitic and austenitic steel, nickel-base alloys) are analyzed based on the results of long-standing studies were performed for the materials both in the original state and after long-term aging (to 10000 hour and in some cases up to 50.0000 hour and up) at high temperature (400-900 °C). The greatest changes in properties were found for 20Ch23N18 austenitic steel and EP99 nickel-base alloy (22%Cr) after long-term aging, resulting in topologically close-packed o- and μ-phases precipitations. Thus, EP99 alloy plasticity is decreased to about zero at 20 °C, number of cycles to failure is hundred times reduced thermal fatigue tests. The rate of creep for 20Ch23N18 steel 20X23H18 is 150 times increased.

Results of the investigation of thermocyclic strength of flat corset-type specimens (hour-glass-shape) (Getsov, L. B. et al., Industr. Lab., 1982, 7, 44)* from nine heat resistant alloys on a nickel base with protective coatings: electron-beam, i.e. single-layer system M—Cr—Al—Y, multilayer, dual-layer, diffusion, slurry and plasma spray coatings are represented. It is shown that the service life of electron-beam coatings is considerably higher than that of the pack cementation and slurry alumosilicide coatings. Dual-layer overlay coatings with an external ceramic layer have the optimum characteristics. Regularities are established for microcrack initiation and propagation in coatings and high-temperature alloys, depending upon the technology of the coating's deposition and test conditions.

Criteria for remaining life estimation and methods for enhancing fatigue resistance of heavy-duty gas turbine bucket metal are based on the analysis of changes in the structure and properties of metal after long-term operation. High-cycle fatigue (HCF) resistance is shown to be a decisive characteristic in the residual life estimation of turbine buckets after operation over 100,000 hours. The tests of the buckets from cast and wrought nickel-based alloys after long-term operation demonstrated decreasing of fatigue strength by up to 25%. The metal structure in operation undergoes notable deterioration mainly in phase redistribution. The size and configuration of metal phases are changing also. It caused the changes in metal properties. The decrease of the bucket fatigue strength correlates with the decrease of metal ductility. The reconditioning heat treatment resulted in restoring mechanical properties of metal. The fatigue resistance also increased nearly to the initial level. The influence of operational factors on bucket fatigue strength deterioration has been established. The mechanical damages on bucket airfoil may decrease the fatigue resistance. We found the correlation of endurance limit and damages depth. The procedures for metal properties recovering and buckets service life substantial extension have been developed. It has resulted in the extension of the buckets service life by up to 50% over the assigned life in gas turbines operated by Gazprom.

Damage to multilayer coatings under thermal cyclic loading is investigated. The mechanisms of crack formation are established and studied as a function of the composition of the coatings, the base metal, and the form of cycle. On the basis of these results, we suggest a composition of multilayer coating with high heat resistance.

The method of physicochemical phase analysis is used to study the carbide phases in heat-resistant nickel-base alloy ZhS-32 after different variants of heat treatment and aging in the temperature range of 850 – 1250°C. MC, M23C6 and M6C carbide phases are detected.

A computational‐experimental approach to analysis of long‐time processes of mass transfer of aluminum in metallic MCrAlY coatings of gas‐turbine blades and to prediction of their service life is proposed. The approach is based on the mathematical model describing the oxidation and diffusion processes in the coating and in the alloy of a blade, the parameters of which are identified by the data of short‐time experiments. The results of theoretical and experimental determination of the aluminum‐concentration distributions in the coating and in the basic alloy of a gas‐turbine blade and the results of prediction of the service life of the coating are presented. It is shown that this approach allows one to perform analysis of long‐time processes of mass‐transfer in metallic coatings of gas‐turbine blades and predict their service life with a high degree of accuracy.

An experimental and calculation procedure has been developed to determine the corrosion service life of the covering coatings that allows for (a) the relationship between corrosion rate and coating composition, (b) diffusion redistribution of elements in the coatings that takes place during a long stay at high temperatures, and (c) alternation of the oxide film A12O3 under the layer of ceramics ZrO2 + Y2O3. The procedure makes it possible to calculate the coating longevity using an arbitrary operational model. The experimental part of the research involves the study of the coating elements distribution depending on time and temperature and the determination of general rules governing the growth of the oxide film A12O3 and its critical value loading to fracture of ceramics at thermocyclic loading.

Apparatus has been developed and assembled to obtain holograms of a living cell culture by methods of digital and analog holography. The setup demonstrates the advantages of both methods and provides convenient adjustment and monitoring of its parameters for recording a series of digital holograms. Software processing of the results makes it possible to obtain information concerning the total optical thickness of the test samples and to visualize and measure changes in living neuronal cultures. Variations of the structure and manifestations of vital activity of a primary culture of brain cells have been investigated and compared.

1. Microalloying of ZhS6K with 0.01–0.8% Y leads to formation of yttrium oxide Y2O3, which precipitates in the form of "chains" and "placers", and of intermetallic Ni3Y localized both within grains and along their boundaries, and leads to a reduction in coalescence rate for γ'-phase particles and retardation of the process of M6C carbide formation of acicular form during aging. 2. Structural changes in the alloy, caused by introducing small amounts of yttrium, lead to a reduction by a factor of 1.5–2 in the short-term ductility and impact strength.

Kinematic circuits and static characteristics of curvature transducers for curves,contours,and surfaces are provided. Equations which represent the dynamic properties of transducers have been derived, amplitude-phase frequency characteristics of transducers have been plotted, and on their basis transfer functions have been derived. Transient processes due to sudden variations of the tested curvature are cited. The transducers' dynamics have been investigated on the assumptions that the angular dimensions of the surface segments are small within the measurement base of transducers.

Emission spectrum analysis was used for measuring the levels of such trace elements as copper, manganese, zinc, nickel and silver in blood serum and tissues of the diseased organs in female patients with certain precancerous and precursor lesions of genital tract. It was found that such changes as an increase in serum copper, a decrease in zinc concentration in blood cells and a rise in the levels of zinc and silver in the affected tissues were more pronounced in cases of precancerous lesions than in those of precursor pathology.