Nº 8 (2024)

In this paper, the possibilities of using a non-destructive acoustic method to determine the degree of hydrogenation of titanium alloy VT1-0 are investigated. The features of the use of various acoustic parameters for the construction of engineering techniques for determining the structural state of a titanium alloy at various stages of its hydrogenation are analyzed. A number of computational and experimental methods for determining the mass fraction of hydrogen in a titanium alloy are proposed, based on the use of its acoustic characteristics, which increase the accuracy and stability of the algorithms underlying the calculation part of the methods. The sources of errors of the proposed methods, the limits of their applicability, as well as the requirements for hardware and software for their implementation are analyzed. The results of acoustic measurements carried out on samples from the VT1-0 alloy are compared with the ideas about the patterns of its structural changes during its hydrogenation. The possibility of creating engineering algorithms for assessing the state of the material of products subjected to hydrogenation on the basis of experimental data obtained in order to prevent dangerous degradation of its operational properties is shown.

In this work, to obtain layered materials with the inclusion of hydrogen, Nb/Zr films with different numbers of layers from 50 to 100 were used. The films were sputtered onto a silicon substrate using the vacuum-magnetron method in a specialized installation. The film thickness was varied from 10 to 50 nm. The resulting material was hydrogenated with protons on a TPU electrostatic generator with an energy of up to 1,2 MeV. The optimal modes for deposition of nano-sized metal multilayer Zr/Nb systems have been determined: for a Zr target, the specific power of the sputtering system is 37,9 W/cm², for a Nb target — 26,4 W/cm². A coating with clear boundaries between the individual layers of zirconium and niobium was obtained. It is shown that the optimal modes for studying nano-sized Zr/Nb layers are pressure 700 Pa, power 40 W, frequency 2 kHz, plasma fill factor 12,5 % for coatings with a thickness of individual layers of 100 nm. For coatings with individual layer thicknesses from 10 to 50 nm, the optimal pressure is 650 Pa, power 40 W, frequency 1 kHz. To control properties, the thermopower method is used. It was revealed that after proton irradiation there is an intensive accumulation of hydrogen atoms near the interfaces, which entails a change in the thermopower up to an inversion of its sign. The hydrogen distribution is predominantly bimodal, with local maxima in hydrogen concentration observed at the Nb/Zr interface, and the accumulation at the Zr/Nb interface is significantly lower. Hydrogen localization near the interfaces occurs predominantly in the vicinity of zirconium.

A new method for detecting subsurface solid objects buried in farmlands, such as plastic bottles, wasted cans, etc., has been proposed by applying the technique of infrared (IR) thermography to monitor the temperature of soil surface subjected to solar irradiation. Through both experimentation and simulation, this study parameterizes the influence of environmental factors on IR images and validates the detection capabilities of the method. To verify the feasibility of IR thermography testing, the experimental section of the work is devoted to monitoring aluminum and polyethylene terephthalate cans buried in sand with varying grades of moisture. The dependencies between the efficiency of foreign object detection and their depth are derived. A restoring pseudothermal flux algorithm was used to reduce the impact of lateral diffusion on IR thermographic detection of foreign objects buried in soil. Variations of soil temperature caused by varying solar radiation during multiple day-night cycles are used to improve the detectable diameter-depth ratio. The described technique is efficient and provides no harm to human beings.

The paper is devoted to designing a finite-element model of the eddy current probe for testing the degree of soldering of lap soldered joints of conductive busbars. The method for finite-element model designing is developed, which parameters provide calculations error of signals of finite-element model of eddy current probe below 1.5%. The test results confirm the performance of the eddy current probe, the measurement range for soldered joints defect size from 0 to 100 % and provision of the declared basic absolute error of the degree of soldering measurement of 5 %.

The paper is devoted to the improvement of the method of inverse calculation of elasticity moduli of layers of motorway pavements in the dynamic setting, which involves the analysis of deformation characteristics in the time domain. To solve this problem, the mathematical model of a layered half-space is adapted to the calculation of amplitude-time characteristics of deformation on the surface of the layered medium, and the construction of the corresponding bowls of maximum values of vertical displacements. Adjustment of the calculated values of vertical displacements with respect to the registered experimental displacements in the field was performed. The correspondence between the final values of maximum vertical displacements, amplitude and time characteristics on the surface of the layered medium, and the shapes and areas of dynamic hysteresis loops on the surface of the investigated medium, achieved by adjusting the calculated characteristics relative to the experimental ones, has been demonstrated. For the first time in solving the problem of determining the mechanical parameters of a layered medium, it was proposed to consider dynamic hysteresis loops as one of the parameters characterising them and the correspondence of their calculated and experimental areas as a criterion of the adequacy of the achieved result.

The paper describes the process of carburizing and hardening of 45 and 09G2S steels for the production of samples for the development of a technique for eddy current testing of the quality and thickness of hardened layers on ferromagnetic cores. Structural analysis of samples in the initial state, in the hardened state, as well as after carburizing and hardening was carried out. As a result of metallographic studies it was obtained that the depth of the cemented layer of steel 45 was equal to 250 microns, and in case of steel 09G2C it is in the range of 550-800 microns.

The issues of ensuring the reliability of automated electric spark testing of the continuity of dielectric coatings on metal pipes with diameters up to 1.5 meters in the context of in-line manufacturing are addressed. A simulation of the “high-voltage pulse source – electrode – dielectric coating – metal substrate” system has been conducted. Experimental studies have been conducted to evaluate the load capacity and voltage stability of the Corona 2.2 holiday detector using an improved generator at high capacitive loads.