The article summarizes the state of the art in carbon-reinforced geopolymers. It takes into consideration various types of matrices and types of carbon fibers (CFs). The article shows the growing importance of this composite in the investigation conducted in recent years. Today, it is one of the most promising modern research areas, taking into account the decrease in the prices of CFs and their appearance on the market waste-based CFs, as well as research on new methods of producing CFs from sustainable precursors. The research methods applied in the article are critical analyses of the literature. The results of the literature analysis are discussed in a comparative context, including production methods and the influence of CFs on geopolymer properties. The potential applications for carbon fiber-reinforced geopolymer composites are shown. Additionally, the current research challenges for geopolymer composites reinforced by CFs are presented.

The existing experience of noise and vibration specialists has shown that the problem of noise reduction is very relevant, especially for the mining industry. Traditional methods of dealing with industrial noise are not effective enough. In solving this issue, it is advisable to reduce the noise level at the source of its occurrence through the use of metal alloys with enhanced dissipative properties. The article presents the results of experimental studies of developing steels with increased damping properties for manufacturing perforator parts: bit bodies and drill rods. In this article, the sound pressure level of alloys dependence on the type of heat treatment has been studied, and the optimal content of alloying elements has been established to ensure the development of the ferrite-pearlite structure. This structure is characterized by an increased dislocation density and is the reason for reducing the noise of the drill rod and the body of the perforator bit by 10–12 dB A. In addition, the article establishes the pattern of noise intensity at different frequency intervals for standard and developed alloys.

Purpose. Research aims to study the influence of alloying elements on the properties of steels contributing to the increased sound energy dissipation and reduced acoustic emission in order to develop alloys for the manufacture of mining equipment parts operating in impact mode (drill string and drill bit housing. Methods. Six alloys were developed during the research based on standard steels. Samples were melted in LPZ-1-67 high-frequency induction furnace at a melting temperature of 1700°C. All the samples were made in the form of 50×50×5 mm plates. KazNTU-2017 setup was used to study the impact noise level. The sound signal was calibrated using a ZG-10 generator. The results were corrected for atmospheric pressure using a PF-101 piston telephone. The temperature and humidity in the laboratory were maintained at a constant level. Acoustic measurements were made five times, with subsequent averaging of the results. Findings. The developed alloys No. 4 and No. 6 have increased dissipative characteristics, which allows them to be classified as “quiet” steels. This is due to the increased graphite and ferrite content in their structure, which promotes effective absorption of sound energy. Alloy No. 3 has medium dissipative properties due to the presence of residual cementite in the structure. Originality. Alloys No. 3, 4 and 6 have been found to have a damping logarithmic decrement (δ) of 2 times higher, relative scattering (ψ) of 3 times higher, and internal friction (Q-1) also 3 times higher than that of standard steel grades used in mining machine parts. Practical implications. The developed alloys No.3, No.4 and No.6 are recommended to be used in the manufacture of mining equipment parts. Their increased dissipative properties reduce the noise level of drill string and drill bit housing by 10-12 dBA, help increase the service life of units, as well as improve the working conditions of workers in the mining industry.

This study examines the effect of silicon and manganese addition on the phase composition and electrical properties of Al-Fe alloys using both experimental methods and thermodynamic modeling with the ThermoCalc software package. This research focuses on the Al–Fe–Si–Mn system, which shows potential for developing conductive aluminum alloys with enhanced performance characteristics. It was found that when silicon and manganese are added in amounts up to 0.6%, the formation of intermetallic phases such as Al₈Fe₂Si and Al₁₅Mn₃Si₂ occurs. These phases significantly influence the electrical conductivity and mechanical stability of the alloy. Thermodynamic modeling proved effective in predicting phase formation, guiding the selection of alloy compositions, and optimizing heat treatment parameters. The optimal composition for a conductive aluminum alloy includes up to 0.8% Fe, 0.5% Si, and 0.6% Mn. Heat treatment in the range of 500–550 °C resulted in a favorable combination of strength, electrical conductivity, and thermal resistance. The findings support the use of Al–Fe–Si–Mn alloys in electrical and structural applications and demonstrate the value of combining computational and experimental approaches in alloy design.

It is specified an interrelation between thermal effects in metals phase transformations and changes in structural parameters (coordination number) of the initial and new phases. It is offered the analytical dependences for calculation of the binding energy and atoms coordination numbers, the metals heat of formation, temperature and thermal effects of phase transitions in metals. It is analyzed the energy parameters of the Periodic System elements considering the type of their crystal lattices. By calculation it is estimated structural parameters of liquid and solid phases, thermal effects and the evaporation temperature of crystallization and polymorphic transformation, and energy formation for 55 elements, for which the literature contains reliable experimental data.