Articles

 


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1.
category: Testing of materials and structures
УДК 629.7.018.4:669.245
FRACTOGRAPHIC RESEARCH OF LOW-CYCLIC FATIGUE FAILURE OF TURBINE DISK BY METHOD OF SCANNING ELECTRON MICROSCOPY
Fractographic research of the mechanism of development of fatigue crack in the turbine disk of alloy ЭП742 in combination application of numerical and analytical methods of calculation intense the deformed condition of alloy in top of crack has allowed to determine by method of scanning electron microscopy the speed of low-cyclic fatigue failure of disk in use.
Keywords: fraktografiya, scanning electron microscopy, low-cyclic fatigue, factor of intensity of tension, nickel-base superalloy EP742, kinetic model of fatigue failure.


2.
УДК 669.295
BEHAVIOUR THE PSEUDO-ALPHA OF TITANIUM ALLOYS AS A PART OF THE STEAM-ELECTRIC EQUIPMENT AT SUPERDESIGN LOADS
Designing of power equipment supposes, as a rule, its behavior under over calculated loaded conditions at a short time. For details and assemblies of steam turbine units, made by high strength weldable pseudo-alpha-titanium alloys, it is necessary to calculate their specific properties for saving serviceability.
Keywords: pseudo-alpha-titanium alloys, power-machine equipment, overloaded conditions.


3.
УДК 669.295
Influence of the corrosion and active environment on fracture toughness of titanium al-loys pseudo-β-class
Results of researches of phase composition, structure, corrosion and mechanical properties of the titanium pseudo-β-alloy ВТ22 forgings are presented. Influence of a microalloying by ruthenium on above-mentioned characteristics of the alloy, including fracture toughness in the corrosive environment is considered.
Keywords: titanium alloys, mechanical properties, corrosion resistance and mechanical strength, microalloying, microstructure.


4.
УДК 669.2:669.131
Development of manufacturing techniques of semi-finished products of alloys of the titanium, excluding defect formation and raising material inspectability
This article generalizes existing experience in production of critical parts of titanium alloys. It gives main approaches to maximum reduction of defectiveness level and increase in homoge-neity of final products. It is shown that quality of charge materials and subsequent remelting are of great importance. A rational approach to material conversion process allows increasing controllability. In this regard process parameters are of paramount importance as well as a correct selection of part geometry by a designer for nondestructive testing. It is also pointed out that a correct selection of a material grade influences structural homogeneity and a result-ing complex of mechanical and service properties.
Keywords: titanium alloys, charge materials, ultrasonic inspection, remelting, deformation.


5.
category: Testing of materials and structures
УДК 621.785.532
Analysis and prognostication of operating failures of the gearbox of the gas turbine engine units after ion nitriding
Analysis of the causes of the typical failures of gears is presented in this paper, and also the method of ion nitriding with hollow cathode effect (HCE) to prevent them is offered. The influence of the ion nitriding with HCE on the microhardness and growth of the hardened layer was investigated.
Keywords: ion nitriding, hollow cathode effect, chemical heat treatment, gear.


6.
УДК 669.245'1:620.178.38
STRUCTURAL CHANGES IN ALLOY EK-61 IN THE CONDITIONS OF CYCLIC DEFORMATION AT ELEVATED TEMPERATURE
It has been shown that at high cyclic deformation at elevated temperatures in high-alloyed iron-nickel superalloy EK-61are forming crystallographically oriented lamellar preciptations identified as -phase Ni3Nb. Generation of -phase precipitates occurs at grain boundaries and incoherent interphase boundaries of carbides (Nb, Ti) C. Revealed that more -phase observed in samples with a high content of niobium within the brand EK-61. Fatigue tests and subsequent structural studies have proofed a decrease of fatigue limit in samples with a high content of -phase.
Keywords: ageing, instability of structure, over ageing, cyclic deformation, fatigue limit.


7.
category: Testing of materials and structures
УДК 621.873:539.4
Destruction of the load gripping device in use
A diagnosis of the technical state of weight-handling straps in operation and those rejected in case of unacceptable damages is completed. A comprehensive study of mechanisms’ and causes of accidental destruction of the strap bracket has been conducted. The results of experiments and calculations are provided.
Keywords: weight-handling straps, diagnosis, safety, damages, defects, destruction, durability.


8.
УДК 620.193
Choice of materials for closing valves in the conditions of oil refining
The material choice for the equipment working under the influence of hostile environment, pressure and temperatures assumes integrated approach to tests. In this work steel 20Х13 researches for the purpose of assessment of possibility of its application for manufacturing of valves maintained in the conditions of oil refining are conducted.


9.
category: Composite materials
УДК 620.197
Maksimov V.G.1
  • [1] Federal State Unitary Enterprise All-Russian Scientific Research Institute of Aviation Materials State Research Center of the Russian Federation
  • HIGH TEMPERATURE CERAMIC HEAT INSULATION (review)
    Keywords: Ceramic composite oxide-based materials last years more and more use in environments where metal materials exhibit a tendency to creep and oxidation. Aluminum oxide is one of the most promising ceramic materials for a wide range of applications in extreme conditions thanks to its combination of high hardness, heat resistance, chemical inertness, with its accessibility and efficiency. However, the use of alumina-based materials in loaded conditions is limited for the low impact resistance, typic