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This work investigates the effect of carbon nanomodification on the residual stress-strain state (SSS) after molding. One of the ways to reduce residual stresses and deformities is nanomodification. The main objective was to determine the degree of influence of the nanomodification parameters on the residual SSS. Within the framework of this study, 4 slabs were made. Two slabs are made of a conventional binder with laying [010/9010] and [010/4510] and two slabs of a modified binding material with the same layer structure. For the fabricated plates, deflections were measured on each of the four sides, during which residual strains were obtained in the panels of nanomodified carbon fiber for the considered layings with and without modified binding material. To analyze the residual stress-strain state, a numerical and analytical calculation was performed. The numerical calculation was carried out by means of the finite element method for the case when the slab is fixed at the point of the geometric center, with no power load, and the temperature load is a difference of 100 °C. An analytical calculation was carried out for the case when the slab is free from fastening and external power load, and the temperature load is a difference of 100°C. During the study, variants of the physicomechanical properties of the monolayer were obtained using the Digimat software and the Mori-Tanaka averaging method. The results obtained by analytical and numerical methods have a good correlation between each other, and in the course of comparison with the experiment, a method for calculating the characteristics of the monolayer that was closest to the experimental result was determined. On the basis of the obtained results, conclusions were made on the possibility of reducing residual SSS and deformation in structures with asymmetric reinforcement schemes using a matrix containing carbon nanoparticles. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of investigations of degradation processes that occur in the structure promising high-temperature anti-oxidizing of heat-resistant coating of the Si–TiSi2–MoSi2–B–Y system in hypersonic flows of air plasma. The coating is designed to protect a wide range of heat-resistant materials (carbon–carbon and carbon–ceramic composites, coal–graphite materials, alloys based on Nb, Mo, W, etc.). It is found that the coating operating capacity at surface temperatures T w ≤ 1820–1830∘C is provided by the structural-phase state of its microcomposite main layer and formation on the coating surface of a heterogeneous passivating protective film. It is based on borosilicate glass reinforced by rutile microneedles. The mechanism of coating destruction at T w ≥ 1850–1860∘C is erosion loss of oxide film as well as generation and growth of gas-filled cavities at the "coating main layer–oxide film" interface. As the pressure of saturated vapor of gaseous oxidation products (SiO, CO, MoO3 and B2O3) exceeds that of the ambient, the oxide film integrity is disrupted and oxidation process becomes active. The rates of erosion loss and sublimation grow as operating temperature increases and ambient pressure decreases. [ABSTRACT FROM AUTHOR]