卷 511, 编号 1 (2023)

With the help of wire arc additive manufacturing, a HEA of AlCrFeCoNi was prepared: of a non-equiatomic composition, on which a B + Cr film with a thickness of ~1 μm was deposited by plasma-assisted RF sputtering. Subsequent processing consisted in electron-beam irradiation of the surface with the following parameters: energy density 20–40 J/cm², pulse duration 200 μs, frequency 0.3 s^–1, number of pulses 3. A quasi-periodic distribution of chemical elements (at. %) 33.4Al; 8.3Cr; 17.1 Fe; 5.4Co; 35.7 Ni is established. It is shown that at the energy density of the electron beam E_s = 20 J/cm², the microhardness increases by a factor of 2, wear resistance by a factor of 5, and the friction coefficient decreases by a factor of 1.3. High-speed crystallization of the surface layer leads to the formation of a subgrain structure with subgrain sizes (150–200 nm). The increase in strength and tribological properties during electron-beam processing is interpreted taking into account the reduction in grain size, the formation of chromium and aluminum oxyborides, and the formation of a solid solution of boron incorporation into the HEA crystal lattice.

In the expanding Universe, the evolution of quantum black holes with the modified Schwarzschild and Reissner–Nordström geometries is considered. All quantum black holes at definite moments of the cosmological time lose event horizons and are transformed to gravitating objects with masses M.

In this paper presents the results of a study of the behavior of surface plasmon polaritons in the layered structure of VO₂–SiO₂-graphene-based hyperbolic metasurface under the influence of an external magnetic field before and at the beginning of the phase transition of vanadium dioxide. As a result of calculations, it is shown how the Isofrequency contour of surface plasmons changes taking into account the different direction of the external magnetic field. It is also shown how an external magnetic field affects the direction of static magnetization caused by the inverse Faraday effect. This work can offer additional ways to control the behavior of surface plasmons, as well as become the basis for the study of new self-adjusting structures.

In conditions of high-temperature creep, the evolution of the damage of metallic materials is observed. To describe this effect, the damage conception of the Kachanov-Rabotnov is used. The damage parameter is defined as the relative changes of the material density, which is an integral characteristic of the damage. Taking into account this parameter and the law of conservation of mass, interrelated kinetic equations for creep deformation and damage parameter are formulated. Analytical solutions of these equations are obtained for the case of two-stage loading. Experimental studies of uniaxial stress state under conditions of high-temperature creep under two-stage loading of aluminum alloy ENAW 5251 (AMg2) at a temperature of 250°C were conducted. A good agreement of the obtained theoretical curves with the experimental results is observed.

Based on the energy approach to the brittle fracture process, a new energy criterion of fracture is obtained in the case when an arbitrary normal symmetrical load acts on the surface of an isolated crack.

Forced nonlinear oscillations of a gas bubble in a liquid are investigated when the frequency of fluctuations in the external pressure of the liquid is equal to the natural frequency of the bubble (resonance). By the method of averaging, a simple formula is derived for the dependence of the oscillation amplitude of a gas bubble on the amplitude of the external pressure and the thermophysical characteristics of the gas and the viscosity of the liquid. Its good agreement with numerical calculations is shown up to the value of the oscillation amplitude of the bubble radius comparable to its equilibrium value.

This paper presents an approach for designing the compact and miniature infra- and low-frequency vibration isolation systems based on the layered composite elastic elements with adjustable negative and quasi-zero stiffness. New problems of modeling the specified parameters of stiffness and bearing capacity of the elements of a certain geometry under combined mode loading are solved by varying the structure, elasticity and configuration of the layers, and by controlling the local mobility of the binder. The approach is valid with the results of experimental designing and studying the system models. Application of the approach makes a qualitatively change in solving a number of critical issues of vibration and noise control in the aerospace and other promising engineering.

A new architecture of photosensitive elements for the near (0.7–1.4 μm) and short-wavelength (1.4–3.0 μm) infrared regions of the spectrum based on hybrid nanostructures consisting of PbS colloidal quantum dots and functional layers of ZnO and AgNW silver nanowires is proposed. Small-sized (12 × 12 μm) photosensitive elements with an energy barrier at the contact between layers of n- and p-type CQDs have been studied. The current-voltage characteristics, spectral dependences of optical absorption and relative spectral photosensitivity of S_i(λ)/S_i(λ_max) barrier structures at room temperature have been studied. It is shown that the proposed architecture of barrier structures provides photosensitivity in a wide spectral range from 0.4 µm to 2.0 µm. An excess of the average value of the relative spectral sensitivity S_i(λ)/S_i(λ_max) about 1.5 times compared to those previously observed in the wavelength range of 0.9–1.85 μm for barrier nanostructures from PbS CQDs was found.