scholarly journals Materials and technologies of powder metallurgy in components of aviation and space engineering

2020 ◽  
Vol 65 (3) ◽  
pp. 272-284
Author(s):  
A. Ph. Ilyushchanka ◽  
A. K. Kryvanos ◽  
Ya. Ya. Piatsiushyk ◽  
V. A. Osipov ◽  
S. G. Baray
Keyword(s):  
Phase Composition ◽  
Powder Metallurgy ◽  
High Efficiency ◽  
Component Composition ◽  
High Temperature Synthesis ◽  
Charge Mixture ◽  
Initial Charge ◽  
Transparent Materials ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics

Examples of the implementation of powder metallurgy methods and their individual elements in the processes of producing materials with special properties and products thereof are considered. The possibility is shown and the results of producing radar-absorbing and radar-transparent materials in the form of solid bodies and coatings are evaluated. The addition of technological transitions, traditional for powder metallurgy, providing in general the production of radar-transparent materials, with the processes of mechanically activated synthesis and mechanically activated self-propagating high-temperature synthesis at the stages of preparing powders for molding, makes it possible to make the transition to the production of radar-absorbing materials. The high efficiency of both has been confirmed experimentally. The transition from a single-component composition of the initial charge mixture through the formation of the phase composition of the material due to the inclusion of powder components into the mixed charge, the composition and crystal structure of which remain unchanged at all stages of its preparation, to the synthesis of the required phase composition due to the interaction of powder components at one of the stages of technological conversion makes it possible to synthesize, for example, silicon carbide ceramics directly in practically useful products, particularly, substrates of optical mirrors for remote sensing of the Earth. The technological operations developed in powder metallurgy have become a background for the production of energy-saturated heterogeneous composite materials. Actively developing additive technologies, as a relatively new branch of powder metallurgy, expands its capabilities practically boundless.

The Effect of SiC Content on Pressureless Sintered Si2ON2-SiC Ceramic

2012 ◽  
Vol 562-564 ◽  
pp. 27-30
Author(s):  
Zhu Xing Tang ◽  
Hui Hui Tan ◽  
He Zhang ◽  
Ke Zhou Xu ◽  
Ying Zhang
Keyword(s):  
Silicon Carbide ◽  
Phase Composition ◽  
Silicon Oxynitride ◽  
Pressureless Sintering ◽  
Silicon Carbide Ceramic ◽  
Ceramic Samples ◽  
Sic Ceramic ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics ◽  
Sintering Method

The Si¬2ON2-SiC ceramic was fabricated by pressureless sintering method. In this paper we researched the effect of SiC content (50%, 70% and 90%) on the performance of silicon oxynitride bonded silicon carbide ceramics. Through testing and analyzing the SEM, XRD, density and porosity of the final silicon oxynitride bonded silicon carbide ceramic samples, the results show that: changes in SiC content not only affect the bulk density of the composites but also affect the phase composition and the microstructure of fracture surface. The most compactness experimental product is sintered at1500°C containing 50wt% SiC.

scholarly journals Specific features of formation of bulk porous systems in the self-propagating high-temperature synthesis. Borides

2019 ◽  
Vol 64 (1) ◽  
pp. 14-24 ◽  
Author(s):  
V. V. Klubovich ◽  
M. M. Kulak ◽  
B. B. Khina
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Structure Formation ◽  
Grain Refinement ◽  
The Self ◽  
Synthesis Process ◽  
Temperature Synthesis ◽  
Thermal Factor ◽  
High Temperature Synthesis ◽  
Initial Charge

The effect of ultrasound oscillations (USO) on the combustion velocity and temperature, phase composition and microstructure of compounds produced by the self-propagating high-temperature synthesis (SHS) in the Ti–B system is studied using the earlier developed experimental setup. It is shown that the effect of powerful ultrasound on SHS is connected with the thermal factor, viz. the enhancement of heat removal from the specimen surface due to forced convection, and the physical (non-thermal) factor that consists in the influence of USO on the melt spreading and crystallization of different phases in the SHS wave. It is demonstrated that for multiphase system Ti–B an increase of the boron content in the initial charge leads to grain refinement of the synthesized product and the imposition of USO on the SHS results in a change in the grain morphology: their shape becomes closer to equiaxial. In composition Ti+1.5B, under the action of USO cubic-shape product grains are observed on the inner surface of pores, and in composition Ti+2.0B the synthesized TiB2 grains become more vividly facetted.As a result of imposition of ultrasound on the synthesis process, grain refinement is observed for all the compositions along with the formation of a large number of borides and their redistribution in the volume. The use of ultrasound brings about changes in the quantitative phase composition of the synthesis products and the ratio between the orthorhombic and cubic modifications of phase TiB. The research has shown that the presence of pores in the initial charge plays an important role in the structure formation of the final product, and hence it appears impossible to obtain an equilibrium material by the SHS method. It is found that an optimal USO amplitude exists at which it is possible to obtain uniform fine-grained structure of the material. This permits controlling the structure formation at SHS. 

Effects of Vickers Cracks on the Mechanical Properties of Solid-phase-sintered Silicon Carbide Ceramics

2012 ◽  
Vol 27 (9) ◽  
pp. 965-969
Author(s):  
Xiao YANG ◽  
Xue-Jian LIU ◽  
Zheng-Ren HUANG ◽  
Gui-Ling LIU ◽  
Xiu-Min YAO
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Solid Phase ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics ◽  
Sintered Silicon

Vickers indentation crack analysis of solid-phase-sintered silicon carbide ceramics

2013 ◽  
Vol 39 (1) ◽  
pp. 841-845 ◽  
Author(s):  
Xiao Yang ◽  
Xuejian Liu ◽  
Zhengren Huang ◽  
Xiuming Yao ◽  
Guiling Liu
Keyword(s):  
Silicon Carbide ◽  
Solid Phase ◽  
Vickers Indentation ◽  
Crack Analysis ◽  
Indentation Crack ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics ◽  
Sintered Silicon

scholarly journals Surface Nitridation of Silicon Carbide Ceramics

1989 ◽  
Vol 97 (1131) ◽  
pp. 1348-1353
Author(s):  
Tadahisa ARAHORI ◽  
Nobuya IWAMOTO
Keyword(s):  
Silicon Carbide ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics

scholarly journals High-temperature oxidation behavior of reaction-formed silicon carbide ceramics

1995 ◽  
Vol 10 (12) ◽  
pp. 3232-3240 ◽  
Author(s):  
Linus U.J.T. Ogbuji ◽  
M. Singh
Keyword(s):  
Silicon Carbide ◽  
Weight Loss ◽  
Oxidation Product ◽  
Oxidation Behavior ◽  
Light And Electron Microscopy ◽  
Initial Weight Loss ◽  
Temperature Oxidation ◽  
Carbide Ceramics ◽  
High Temperature Oxidation Behavior ◽  
Silicon Carbide Ceramics

The oxidation behavior of reaction-formed silicon carbide (RFSC) ceramics was investigated in the temperature range of 1100 to 1400 °C. The oxidation weight change was recorded by TGA; the oxidized materials were examined by light and electron microscopy, and the oxidation product by x-ray diffraction analysis (XRD). The materials exhibited initial weight loss, followed by passive weight gain (with enhanced parabolic rates, kp), and ending with a negative (logarithmic) deviation from the parabolic law. The weight loss arose from the oxidation of residual carbon, and the enhanced kp values from internal oxidation and the oxidation of residual silicon, while the logarithmic kinetics is thought to have resulted from crystallization of the oxide. The presence of a small amount of MoSi2 in the RFSC material caused a further increase in the oxidation rate. The only solid oxidation product for all temperatures studied was silica.

Resonant ultrasound spectroscopy of silicon carbide ceramics SiC‒AlN

2021 ◽  
pp. 136-140
Author(s):  
E. G. Pashuk ◽  
G. D Kardashova ◽  
Sh. A. Khalilov
Keyword(s):  
Silicon Carbide ◽  
Elastic Moduli ◽  
Ultrasonic Spectroscopy ◽  
Resonant Ultrasound Spectroscopy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Complete Set ◽  
Resonant Ultrasound ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics

The paper discusses the possibility of using resonant ultrasonic spectroscopy (RUS) as a source of information for the physics and technology of obtaining silicon carbide ceramics by the example of samples of the composition SiC ‒ 25 % AlN, obtained by the method of spark plasma sintering. The possibility of obtaining a complete set of elastic moduli (EM) of samples with an error of less than 1 % is shown. At the same time, the requirements for surface quality are significantly reduced. The revealed functional relationship between EM and porosity makes it possible to create a non-destructive method of porosity control and calculate the elastic moduli at zero porosity (i. e., the elastic modulus of the ceramic matrix EM0). Comparison of EM0 samples obtained at different parameters of the technological process allows determining their optima values..

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