№7 2022
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1
The article is devoted to the development of technology for smelting and deformation of VNS-74 (05Kh16N5AB) corrosion resistant steel with an increased nitrogen content (more than 0.10 % by weight). The structure and its influence on the hardness and strength characteristics of calibrated bars (different sections from 6 to 16 mm), made of steel VNS-74 by cold and hot deformation, are considered. The high technological plasticity of thin rods in the cold state, which is necessary for carrying out the operation of cold upsetting of the bolt heads, is shown. The mechanical properties and stress corrosion resistance of cold and hot heading bolts with 8° misalignment under the head and under the screw-nut and without misalignment were studied.
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2
The paper defines two groups of defects characteristic of single crystals of NGC: substructure and blockiness. The most common causes of their occurrence are considered. The comparison of the main methods of substructure control: visual, swing and Laue and the results of determining the disorientation of the substructure by the method of swing relative to the longitudinal axis of the casting and the complete disorientation of the substructure determined by lauegrams is given. Based on the comparison, a conclusion is made about the limits of sensitivity during visual inspection of the structure.
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3
Properties of not modified fenolformaldegidny adhesives, their structure and assignment are shown. Examples of adhesives on the basis of fenolformaldegidny resins, modified by polyvinylacetals are given. Improvement of properties of adhesives after their updating in such a way is shown. Strength characteristics of the adhesives joints executed with use of phenolopolyvinylacetal adhesives of brands VS-10T-U and VS-350 in initial condition and after artificial factors, simulating the operational are provided. It is shown that adhesives VS-10T-U and VS-350 provide operability of high-temperature tenzorezistors.
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4
This paper presents the technological features of the processing of glass-reinforced plastics based on PMR-type polyimide binders. The main approaches to the manufacture of polymer composite materials (PCM) samples based on glass fillers and polyimide melt binders are demonstrated, taking into account their physicochemical features. It was shown that PCM based on melt-type polyimide binders can be processed according to different modes, providing different levels of characteristics.
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5Part 2
Polymer composite materials (PCM) are increasingly replacing traditional materials. New PCMs are constantly being developed, which are more economical and at the same time provide high-quality manufacturing of parts and structures from them. The infusion process has a well-established position among such processes as automated winding and automated prepreg lay-up followed by autoclaving. However, when using autoclave technology, there are restrictions on the dimensions of the molded parts, in addition, this method is quite expensive to operate. Therefore, the infusion process is increasingly used in the manufacture of parts in aircraft and shipbuilding, the construction industry, etc.
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6
Presents the results of a study of the resistance to oxidation of various types and manufacturers carbon fibers by exposure to a given temperature for a certain time. High-strength carbon fibers with standard and intermediate Young’s modulus were investigated. The obtained results of short-term and long-term tests correlate with the results of thermogravimetric analysis. It is shown that among the studied fibers, high-strength carbon fibers with intermediate Young’s modulus have the greatest thermal oxidative resistance.
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7
The article describes the most technologically advanced methods of preparation of the surface of aluminum alloy 1163-AT samples before the application of electrolytic coatings. Information about the influence of the selected methods of sample surface preparation on the adhesion strength of the electrolytic nickel coating to the substrate is provided. It is shown that the use of a sublayer can affect the smoothing of the microtopology and cause a decrease in surface roughness after the deposition of an electrolytic nickel coating 12 μm thick.
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8
In mechanical engineering, coating by cold gas-dynamic spraying (CGN) is most often used to eliminate mechanical damage (cracks, scratches) and defects, as well as to provide corrosion protection on steel parts. Improving the effectiveness of protective coatings applied by the CGN method by creating new powder materials is the main task of research in this area.
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9
The article covers the problem of transformation of hydrophilic-lipophilic properties (HLP) of various surfaces as a way to improve the functionality and increase the duration of their maintenance. A quantitative assessment of the relevance of the topic according to the Internet platform sciencedirect.com is presented. The main provisions and concepts related to HLP materials are briefly described. The types of amphiphilic molecules, types and classes of systems for hydrophobization are considered. A predictive analysis of the modern market was performed.
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10
The content of impurities of 33 elements (Li, Be, B, Na, Mg, Al, P, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb , Sr, Zr, Mo, Cd, Cs, Ba, Re, Tl, Pb, Bi, Th, U) in a praseodymium sample by inductively coupled plasma mass spectrometry (ICP-MS). The technique of sample dissolution and its preparation for analysis is given. Spectral interferences are eliminated by applying mathematical correction equations, a reaction-collision cell, and by adjusting the plasma power.
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11
Estimation of impact damages area in CFRP specimens after impact is described at the article. It is shown that nondestructive testing and damages sizes estimation can be carried out by ultrasonic through transmission, echo and mechanical impedance analysis techniques. A comparative analysis of the estimation of impact damages areas by these techniques was carried out. The best accuracy in estimation of impact damages sizes can be obtained by using an automated ultrasonic echo technique in combination with focused transducers, as well as ultrasonic phased arrays.
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12
Presents the results of studies of the fire safety parameters of high-temperature carbon fiber reinforced plastics made on the basis of various heat-resistant polymer binders, conducted in order to determine the possibility of their potential application in the designs of aircraft products, from the point of view of compliance with the requirements of regulatory documents in the field of aviation fire safety. It is shown that the considered carbon plastics have high values of fire safety characteristics and can be used in aircraft products.
