High-temperature Composite Materials Research Articles

Research on High Temperature Friction and Wear Characteristics of H13-Cr2C3-CaF2 Self-lubricating Materials

Based on the service environment and requirements of hot working die,we proposed a H13-Cr2C3-CaF2 self-lubricating material formula system and powder metallurgy process parameters, and prepared the high temperature composite materials. The phase composition and distribution of H13-Cr2C3-CaF2 samples were analyzed by energy dispersive spectrometer. The friction coefficient, wear rate, wear morphology and spectrum of samples with different contents of CaF2 were tested and compared by ball-on-disc high temperature tribometer under the conditions of test temperature 600 °C, disk rotation speed 200 r/min and friction for 15 min,and the mechanism of high temperature friction and wear was described. It will support the green manufacturing and sustainable development of forging industry.

Design, structure and properties of organomorphic composites as new materials

Reinforcing basis of high-temperature composite materials conventionally consists of derivatives of multifilament fibers: fabrics, rods, plaited yarns, etc. Another example of an appropriate preform is a biomorphic preform (BP) obtained by pyrolysis of wood. On the one hand, organomorphic preforms (OP) are prepared based on filaments of organic precursors of carbon, silicon carbide, and carbonitride fibers – polyacrylonitrile, polycarbosilane, and polysilazane, respectively. On the other hand, nonoxidizing pyrolysis of densified bundles of such fibers is used as in the case of BP. Autohesion interaction occurring upon contact of compressed polymer filaments during the initial stage of pyrolysis inherits at compression kept up to OP transition into inorganic state. As a result, uniform dense (0.4–0.5 of ρfiber) strong preforms are formed with narrow and very small equivalent diameter of pores: from few to 30–40 µm. Reinforcement in preforms can be uni-, bi- or three-directional. Subsequent densification of OP by vapor or liquid phase methods allows obtaining organomorphic composites (OC) with improved properties, some of which (gas permeability, surface roughness, capability of making articles with thickness of no more than 0.3 mm) are unattainable for existing high-temperature structural composites.

Methods for the Simulation of the Aerodynamic Heating Conditions of the Structural Elements of Space Shuttles

The paper considers the problem of creating and operating products of reusable space-rocket hardware, in particular with respect to ensuring the integrity of structural elements and safe return to Earth under aerodynamic heating conditions. This problem has two aspects, which differ in specificity of the approaches to designing the elements of space shuttle systems (SSS). The first aspect is associated with ensuring the reliable functioning of the most thermally stressed elements of the re-entry glider, which are structures with large angles of attack, such as fuselage nose and leading edge, wing loading edge, elevators and air intake edges. The second aspect mainly concerns ensuring the allowable temperature level of the spacecraft pressure shell on all flight path segments, especially during re-entry in the Earth’s atmosphere. In view of this, one of the main goals in creating SSSs is to develop a reliable heat shield having acceptable size and weight parameters, and cost. The successful solution of these problems is determined in many respects by the optimal choice of appropriate classes of materials: special high-temperature alloys, structural ceramics, highmelting-point metallic and polymeric composite materials. For the modern structures of SSSs, the use of structural metallic materials is worth-while in many respects. Rig test procedures are proposed. A complex of gas-dynamic test rigs was used as the basic equipment, whose fundamental design features and methodological solutions ensure the complete rig test cycle for the solution of problems in both directions. The methodological basis of rig tests is a set of specialized procedures for the simulation of thermally stressed states of the material and the intesity of the external action of the environment, which provide the equivalence of material damage processes and the limit state of the structural element under investigation under model and full-scale conditions. The fundamental basis of these approaches is the classical similarity and dimensional theories, the main postulates of which have been transformed and adapted to the problems of the study of the strength of materials and damageability of structural elements under thermal cyclic loading in corrosive environments. The developed procedures and experimental means allowed the modeling of aerodynamic heating processes of the structural elements of space shuttles. It has been shown that the implemented methods enable the evaluation of functional characteristics, determination of a set of properties and refinement of the technology for the formation of structural elements of aerospace vehicles operating under the conditions of aerodynamic heating to extremely high temperatures.

Studying the Possibility of Obtaining High-Temperature Composites via Mechanochemical and Electron-Beam Treatment

Mechanochemical and electron-beam treatment allow new high-temperature composites to be obtained faster and with less consumption of energy. Model experiments on obtaining the high-temperature composite materials are performed using a combination of tungsten and titanium diboride powders.

Utilizing blast furnace slags (BFS) to prepare high-temperature composite phase change materials (C-PCMs)

Blast furnace slag (BFS) is a typical solid waste generated in the steel production. Most of previous investigations have reported that the BFS has been used as traditional construction materials (cement, roadbed filling, concrete). In this study, a novel use route for BFS was proposed to prepare high-temperature composite phase change materials (C-PCMs) for thermal energy storage. Three typical inorganic PCMs (NaNO3, Al and Na2SO4 with different operating temperature) were blended with the pre-ground BFS to fabricate BFS-based C-PCMs by means of a mixing and sintering process. The results showed that NaNO3 had excellent chemical compatibility with BFS and the prepared C-PCMs had perfect phase change performance. The enthalpies of NaNO3/BFS C-PCMs was 65.53 J/g with melting point 300.5 °C and the super-cooling was only 0.1 °C. Furthermore, the NaNO3/BFS C-PCMs could retain good thermal reliability after 100 thermal cycles, which presented a potential application in the thermal energy storage system. In addition, the morphological structure, thermal reliability and heat transfer property of the NaNO3/BFS C-PCMs were characterised by using SEM, TGA and TG-DSC.

ВЫСОКОТЕМПЕРАТУРНЫЕ МЕТАЛЛОМАТРИЧНЫЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ, АРМИРОВАННЫЕ ЧАСТИЦАМИ И ВОЛОКНАМИ ТУГОПЛАВКИХ СОЕДИНЕНИЙ

ВЫСОКОТЕМПЕРАТУРНЫЕ МЕТАЛЛОМАТРИЧНЫЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ, АРМИРОВАННЫЕ ЧАСТИЦАМИ И ВОЛОКНАМИ ТУГОПЛАВКИХ СОЕДИНЕНИЙ

ИССЛЕДОВАНИЕ ТЕРМОХИМИЧЕСКОГО ВОЗДЕЙСТВИЯ ПОТОКА ВОЗДУШНОЙ ПЛАЗМЫ НА ВЫСОКОТЕМПЕРАТУРНЫЙ КЕРАМИЧЕСКИЙ КОМПОЗИЦИОННЫЙ МАТЕРИАЛ

ИССЛЕДОВАНИЕ ТЕРМОХИМИЧЕСКОГО ВОЗДЕЙСТВИЯ ПОТОКА ВОЗДУШНОЙ ПЛАЗМЫ НА ВЫСОКОТЕМПЕРАТУРНЫЙ КЕРАМИЧЕСКИЙ КОМПОЗИЦИОННЫЙ МАТЕРИАЛ

ВЫСОКОТЕМПЕРАТУРНЫЕ РАДИОПРОЗРАЧНЫЕ КЕРАМИЧЕСКИЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ ДЛЯ ОБТЕКАТЕЛЕЙ АНТЕНН И ДРУГИХ ИЗДЕЛИЙ АВИАЦИОННОЙ ТЕХНИКИ (обзор)

ВЫСОКОТЕМПЕРАТУРНЫЕ РАДИОПРОЗРАЧНЫЕ КЕРАМИЧЕСКИЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ ДЛЯ ОБТЕКАТЕЛЕЙ АНТЕНН И ДРУГИХ ИЗДЕЛИЙ АВИАЦИОННОЙ ТЕХНИКИ (обзор)

Experimental study on the transient thermal characteristics of an integrated deflector under the periodic impingement of a supersonic flame jet

The flow deflector effectively facilitates thermal spreading and the split of high-temperature gas flow from jet impingement. In this study, we developed two samples of integrated deflectors with four layers. The first sample consisted of a composite of silicon carbide reinforced with carbon fiber (C/SiC), carbon aerogel, silica aerogel, and a sandwich corrugated plate. The second sample replaced carbon aerogel with lithium fluoride (LiF), a high-temperature composite material of phase change. Under the periodic impingement of a supersonic flame jet, the transient thermal response of the two deflectors was investigated experimentally. The thermal image of the impinged surface was obtained by an infrared camera. After four periods, the periodic temperature variation in this surface stabilized. The thermal disturbance propagated and attenuated gradually from the impinged surface to the corrugated plate back surface. The back surface temperature of corrugated plate increased monotonically with impingement period without any fluctuation. The entire temperature of the deflector was effectively controlled in the range from 3400K (the total gas temperature) to 480K at the centerpoint of the back surface of the sandwich corrugated plate without incurring thermal damage. The deflector temperature level and the ablation rate of the impingement surface were lowered further using LiF as a thermal shield layer because of its high storage of latent energy.

Research on Expanded Graphite/Nitrate High-Temperature Composite Phase Change Materials

In order to enhance the thermal conductivity of high-temperature phase change materials (PCMs), expanded graphite (EG) /NaNO3-LiNO3 composite was prepared by the method of eutectic aqueous solution infiltration porous structure of EG. The composites with an EG amount of 10%, 20% and 30% were prepared in the similar way. The results proved that the eutectic was an excellent PCM, for its melting (solidification) temperature was 193.7 (191.7) °C, and its latent heat was 272.6(262.6) kJ/kg. With the increasing in graphite amount, the thermal conductivity of the composite was found to progressively increase with intensifications up to 10. We can conclude that the saturated water solution method was a simple and effective way to strengthen the thermal conductivity of the eutectic.

ИССЛЕДОВАНИЕ МИКРОСТРУКТУРЫ ВЫСОКОТЕМПЕРАТУРНОГО ЕСТЕСТВЕННО КОМПОЗИЦИОННОГО МАТЕРИАЛА НА ОСНОВЕ НИОБИЯ, УПРОЧНЕННОГО ИНТЕРМЕТАЛЛИДАМИ СИЛИЦИДА НИОБИЯ

ИССЛЕДОВАНИЕ МИКРОСТРУКТУРЫ ВЫСОКОТЕМПЕРАТУРНОГО ЕСТЕСТВЕННО КОМПОЗИЦИОННОГО МАТЕРИАЛА НА ОСНОВЕ НИОБИЯ, УПРОЧНЕННОГО ИНТЕРМЕТАЛЛИДАМИ СИЛИЦИДА НИОБИЯ

A micromechanical approach for the fatigue failure prediction of unidirectional polymer matrix composites in off-axis loading including the effect of viscoelasticity

A novel micromechanical approach is used to study the fatigue failure of unidirectional polymer matrix composites subject to off-axis loading. The main advantage of the present micromechanical model lies in its ability to give closed form solutions for the effective nonlinear response of unidirectional composites and to predict the material response to any combination of shear and normal loading. The fatigue failure criterion is expressed in terms of the fatigue failure functions of the constituent materials. The micromechanical model is also used to calculate these fatigue failure functions from the knowledge of the S–N diagrams of the composite material in longitudinal, transverse, and shear loadings; thus, eliminating the need for any further experimentation. Unlike previous works, the present study accounts for the viscoelasticity of the matrix material rendering it the capability of modeling creep damage accumulation in high-temperature composite materials. The results are found to be in good agreement with the literature. In particular, for higher off-axis angles, the results are seen to be in better concurrence with the experimental data compared to when the effect of viscoelasticity is overlooked. The present approach is also capable of accounting for the strain evolution due to viscoelasticity of the matrix material.

Promising High-Temperature Composite Materials and Coatings for Aerospace Technology

The problems of developing high-temperature composite materials for aerospace engineering and methods for obtaining them as well as their advantages over the technologies widely used abroad are examined.

Surface treatment and adhesive bonding techniques for repair of high-temperature composite materials

Adhesive bonding of structural aircraft materials depends upon a thorough understanding of factors that affect bond strength and durability. It is well known that surface preparation is critical to adhesive bond performance. However, little information is available regarding the effect of surface preparation procedures on adhesive bonding of high-temperature polyimide composites. Mechanical treatments such as hand sanding are commonly used for composite materials, and in general are known to improve the wettability of the surface as well as effect contaminant removal. Less is known about the influence of mechanical treatments on the surface chemistry. This article discusses the effects of mechanical surface preparation on the adhesive bond strength, durability, and failure mode of several high-temperature polyimide-based composites and adhesives.

Modeling Damage Growth in Oxidized High-Temperature Polymeric Composites

Thermal oxidation is a major degradation mechanism for polymers and composites operating at high temperatures. Controlling the damage progression in oxidative environments is critical for enhancing the long-term durability of these materials. The surface oxidation of the material and the damage evolution in high-temperature polymer matrix composite materials (HTPMCs) are highly coupled mechanisms. In this article, three-dimensional, finite-element methods are used to simulate both oxidation layer and damage growth in polymers subjected to bending loads and laminated composites subjected to uniaxial tension. An oxygen diffusion–reaction model determines the changes in properties due to oxidation and chemical strains induced by oxidation. The damage growth is simulated using mesh-free extended finite-element techniques and suitable damage initiation laws. The damage evolution observed with simulations is seen to be consistent with experimental observations reported in the literature.

Research on the Flame-Retardant Property of Continuous Basalt Fiber Based on Basic Properties of Advanced Composite Materials

In this paper, Continuous Basalt Fiber (CBF) was used as the raw materials, and then woven by the Digital sample looms. Experimental results show that CBF has a very high limiting oxygen index, even if which more than 69%, was much higher than 27% of the indicators of the non-combustible fiber. In the Vertical Burning Test, there was no burning, smoldering, continued burning phenomenon, which can be clearly seen, and the mechanical properties can remain stability in the before-and-after-test. The CBF, would be bound to play a significant role in future of fire-retardant materials and high-temperature composite materials, exhibited excellent flame resistance and heat resistance.

Glass and ceramics based high-temperature composite materials for use in aviation technology

Promising high-temperature glass-ceramic and ceramic composite materials developed at VIAM, are examined. These materials are distinguished by their capability to retain their properties at high temperatures in an oxidative environment, good durability, excellent corrosion properties, low density, and low thermal expansion. In regards to their performance properties these materials are as good as, and in some respects even surpass, the best foreign analogs, making them the only available materials for use in heat-loaded units and the components of prospective articles.

Thermomechanical coupling analysis of heat-pipe-cooled leading edge thermal protection structure with thermal contact resistance

Using heat-pipe-cooled thermal protection structure is a noval efficient thermal protection method, and thermal contact resistance between the heat pipe and high temperature composite material has a significant influence on the thermal protection performances. The computational model of the heat pipe cooled thermal protection structure is given firstly, then the computational scheme of the thermomechanical coupling problem caused by thermal contact resistance is established based on the sequential coupled method. The thermomechanical coupling analysis of the computational model under different initial gaps is performed after that, with an emphasize on the effect of thermal contact resistance. Results show that using initial gap can greatly reduce the stress level of the structure, while increase the interface thermal contact resistance and stagnation temperature. Structure strength and temperature should be considered simultaneously with the thermal contact resistance in structure safety evaluation of structures with initial gaps.

High-temperature composite materials and coatings on the basis of glass and ceramics for aerospace technics

High-temperature composite materials and coatings developed in the RIAM, specifically construction composite materials with glass, glass-ceramic, and ceramic matrices, for use at 700–1500°C, ceramic composites on the basis of poly-carbosilanes, erosion resistant coatings with the effect of thermal control for heat shield systems of perspective aerospace technics, are reviewed. These coatings combine a complex of properties: high radiating capacity, phase stability, thermal shrinkage resistance, resistance against acoustic, vibration, atmospheric factors, etc. Technological coatings to protect steels and Ti and Ni alloys during heat treatment and isothermal and hot die forging are developed. New type enamels, pasts, thick-film electric heaters, etc., are described.

Production of tungsten-based composite materials from mechanically activated powders

The effects of the composition and metal additives on the compressibility of mechanically activated tungsten-based powder mixtures, the volume changes upon sintering, and the structure and strength of high-temperature composite materials are studied.