International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The subject of the article is the planning and comprehensive preparation of an experiment for monitoring the condition of a satellite’s structure under vacuum conditions modelled using a space environment simulator. Simulating the space environment is essential for verifying the performance of materials, structural components and equipment prior to their actual launch. Such testing makes it possible to confirm the correctness of material selection, the accuracy of engineering calculations and the validity of technical decisions made during the design phase. The behaviour of materials under vacuum, extreme temperatures, sharp thermal fluctuations, and exposure to cosmic radiation may differ significantly from their performance under standard operating conditions on Earth.

The influence of external factors (heat treatment, high pressure) on the optical properties of the samples was analyzed. It was established that samples of pure PTFE4 after the specified external influence increase their throughput, while the largest increase in throughput is observed for samples that were obtained under high pressure, and for samples that were subjected to heat treatment during synthesis, an increase in throughput is characteristic ability with increasing synthesis temperature. For PTFE-4 composites from 5 wt. % CNT (film thickness h=200 μm) samples become opaque in the wavelength range λ=320-1000 nm and regardless of the method of their production, which indicates the possibility of using such materials as absorbing coatings.

In this paper, the tensile strength of the composite material made of onyx and carbon fibers was investigated. Onyx is a material manufactured by the company Mark Forged, which is used for 3D printing of composite materials. It is a thermoplastic filled with carbon fibers used for printing solid and rigid parts. The tensile test according to the standard ISO 527 was carried out experimentally and the numerical results were obtained by numerically modelling the test specimen and simulating the test in Ansys, after which the results obtained experimentally and numerically were compared.

X-ray diffraction analysis of the Fe-35%FKh800-(0.38-2.2%)TiB2 system samples showed that a multiphase composition of materials is formed during the sintering process. The basis of the sintered composite is the ferrite α-Fe phase, which is a metallic ironchromium matrix, with γ-Fe, complex iron-chromium carbide (Fe,Cr)7C3, and carboboride phases in small amounts: borocementite – Fe3(B0.7,C0.3) with a rhombohedral lattice and carboboride Fe23(C,B)6 with a cubic lattice and a number of carbides (Cr7C3, Cr3C2). The research established the non-monotonic nature of the effect of the TiB2 additive content on the lattice parameters of the ferrite α-Fe and austenitic γ-Fe phases, as well as on the change in the intensity of the 111 line of the austenitic phase. According to the phase composition data and studies of the fine structure (substructure) of the sintered samples of the Fe-FKh800-TiB2 system materials, it can be noted that the components of the TiB2 alloying additive take an active part in the formation of the phase composition, as well as in the process of alloying the matrix phase, which is reflected in the numerical values of the substructure parameters.

The properties of an array of carbon nanostructures or a material containing its is differ from the properties of individual components. For bulk array of carbon nanostructures it is unknown to what extent the electrons of each layer participate in conductivity, the role of defects is not defined. properties. So, this work presents some answers to these questions.

The electrical and mechanical properties of nanocomposites based on carbon nanostructures has been studied. It is sown that a t a concentration of carbon nanotubes of 15-30 wt. %, the electrical resistance of the samples decreases to 1 order, while its mechanical properties change insignificantly, which is due to the transfer of free electrons from the metal to the CNT, which is comparable to the number of electrical contacts between the constituent elements of the composite and the competition between the numbers of tu nneling and ohmic contacts.

The influence of high-carbon ferrochrome on the features of structure formation and properties of chromium carbide steels based on the Fe-FKh800 system was investigated. It was shown that the optimal combination of hardness and tensile strength with sufficient crack resistance has a carbide base of 65% Fe – 35% (wt.) FKh800. A typical microstructure of sintered carbide is a metal matrix composite consisting of chromium steel of composition close to Kh17 and double carbide (Cr0.799Fe0,201) 7C3. The effect of TiB2 additive on the structure, phase composition, mechanical and tribotechnical properties of materials based on the Fe- 35 (%,wt.) FKh800 system was also investigated. Additions of titanium borides in the amount of 0.38-1.48 (% wt.) leads to some increase in hardness, noticeable increase in the flexural strength and leads to increase wear resistance of carbidosteels.

Heat-resistant composites with a layered niobium-based matrix reinforced with single-crystal sapphire fibers have been obtained. The fibers were grown from the melt by the modified Stepanov method. The composites were prepared by solid-phase technology by diffusion welding of multilayer packages of foils of the Nb–0.1% C and aluminum alloy, interlaid with sapphire fibers in layers of a suspension mixture of Nb powder. The production of fibers, their structure and strength testing procedure are described. The formation of multilayer packets, the structure and results of bending strength tests of composites are presented

The work is devoted to the development of a solid-phase technology for obtaining high-temperature layered composites from Nballoys. The following are presented: one of the options for the formation of the initial multilayer package and its diffusion welding (1), the microstructure of the obtained composites (2) and the results of testing composites (3) for strength at room temperature and temperatures up to 1350°C, taking into account the structure anisotropy, crack resistance and tests for creep with two options for processing the obtained experimental data.

The effect of TiB2 additives on the sintering temperature, structure, and mechanical properties of materials based on the Fe-FeCr800 system is investigated. It was shown that the introduction of titanium diboride additives leads to the activation of compaction and to a 50–70ºС decrease in the sintering temperature of the pressed composites based on iron. It has been studied that the addition of titanium diboride in the range of 0.38-0.74 (% wt.) provides, with a slight increase in hardness, an increase of 20-25% of the flexural strength of the composite 65Fe-35 FeCr800800 (% wt.), and also provides the formation of a multiphase, microheterogeneous structure of the matrix-filled composite type, which consists of chromium steel of the X6Cr17 type, double iron-chromium carbides M7C3, M3C and complex carboborides of the Me3(CB) type.

The influence of temperature of sintering on structure formation, phase composition, microhardness of components of powder composite 65 % wt. Fe – 35 % wt. FH800 were investigated. It has been established that the increase in the temperature of sintering from 1050 ºС to 1250 ºС leads to some increase in volumetric shrinkage, density and decrease in porosity of samples of material which was made from coarse-grained source powders of industrial production components. It was found that the sintering of green compacts in the range of 1000-1300 ºС causes significant changes in the chemical and phase composition of the carbide component of the composite, which are described by a series of phase transformations: M7C3 → M3C (1000-1150 ºС) → M7C3 (1200 ºС) → M3C (1250-1300 ºС)

Although molding of thermoplastics is very productive method of machinery manufacturing, pure plastics are almost not used in so much quantity. Particle reinforced composites are more popular, because presence of solid inclusions reduces volume of organic matrix and usually improve strength and stiffness. Final properties are strongly influenced by manufacturing process which affects inner material structure. In composites where fibers are continuous in one direction or placed in layers, i.e. the fibers do not end inside the composite and it`s length is close to the dimension of machinery parts, elastic [1] [2] and thermal properties [7] can be predicted quite easily by Halpin-Tsai equations or derived simplified methods [2] with high accuracy. This paper is focused on prediction of density and material stiffness of composites, which are reinforced with very short glass fibers in thermoplastic matrix. In the first part we define the field of problem. Then we present simplified analytical calculus in compare to finite element method. We focus on ABAQUS 2018 and its features, which can be used for solving those problems. Estimation approaches such as representative volume element method and mean field homogenization are also studied. After this presented methods are confronted with selected material datasheet of Ultramid® A3WG6 [9] and Zytel® 70G35HSLRA4 [12] composite material. The effect of fiber randomization on material stiffness is introduced [4]. At the end of thesis we use previously calculated material data for modal analysis of real parts which are made from molded thermoplastic with short glass as well.