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

The contact interaction between the metal matrix composite based on Ti64 and the B4C-based composite was investigated. It is shown that the interaction process is influenced by the annealing temperature and holding time. The phase that formed independently of the contact pair is TiB. However, the thickness of the products formed at the boundary depends on the contact pair. In case of the Ti64-B4C pair the thickness is 70 μm, while for (Ti64-40 wt% TiC)-B4C it becomes 10 μm. This significant difference in the thickness is due to the presence of refractory particles (TiC) in (Ti64-40 wt% TiC)-B4C couple, because the TiC phse reduce the diffusion of Ti into the contact zone.

A novel two-stage approach for obtaining wear-resistant multifunctional powder composites based on metal powders with highmodulus Ti–TiC system fillers is proposed. The method combines high-voltage electric discharge (HVED) treatment and spark plasma sintering (SPS), offering a promising alternative to conventional techniques for producing Al–Ti–C system composites. This approach enables the development of a unified route for material synthesis using high-energy-density processing. HVED treatment prevents oxidation of metal particles, reduces contamination by tool materials, and initiates the synthesis of additional dispersed strengthening phases. For example, HVED treatment of titanium powder in a hydrocarbon liquid promotes the in situ formation of titanium carbide (TiC) particles.
The present work investigates the influence of adding Ti–TiC powder—synthesized via HVED in ethanol under reverse polarity mode with a specific energy input of 20 MJ/kg—on the structure, phase composition, and properties of Al–Ti–C metal matrix composites (MMCs). It was shown that the addition of 2 wt% of Ti–TiC powder synthesized via HVED in ethanol to aluminum powder results in an MMC with an electrical resistivity of 0.5 Ω·mm²/m and a hardness of 31 HRB. However, the heat resistance of this composite is 2.5 times lower than that of consolidated pure aluminum powder. Increasing the Ti–TiC content to 10 wt% leads to the formation of a wear-resistant Al–Ti–C composite, whose structure includes Al, Ti, TiC, the intermetallic compound Al₃ Ti, MAX phases Ti₂ AlC and Ti₃ AlC₂ , and free carbon. For the MMC sample with the addition of 10% Ti–TiC, the mass gain per cycle during the heat resistance test is 0.23%/cycle, whereas for samples made from consolidated Al powder it is 0.18%/cycle, indicating that their heat resistance is approximately the same. The wear resistance of this composite is more than three times higher than that of the consolidated base aluminum powder, with wear rates of 0.003 g/km and 0.010 g/km, respectively. This material also demonstrates a hardness of 43 HRB and relatively low electrical resistivity at the level of 0.3 Ω·mm²/m.

The high specific strength of Ti-based alloys and composites makes them highly requested materials in various structural applications. However, reinforcement of the alloys with hard particles generally lowers the values of toughness and plasticity of material. A satisfactory combination of plastic and strength can be achieved by formation of layered structures comprising of two and more layers of different materials with different chemical compositions within individual layers. The multi-layer materials allow controlling the mechanical properties of the individual layers by changing microstructure and chemical composition within each layer specifically. In the present study, a cost-efficient process of fabrication of Ti-based multi-layer composites using blended elemental powder metallurgy (BEPM) and TiH2 powder is proposed. Two and three-layered composites based on titanium or Ti-6Al-4V alloy and their metal-matrix composites (MMC) with TiC and TiB were fabricated. Multi-layered samples reinforced by TiC were successfully sintered due to very close shrinkage of adjacent layers. Shrinkage values of layers reinforced by TiB were lower than those for the Ti-alloy, which led to delamination of layered structures, distortion of shape, and cracking. We can control shrinkage in individual layers by means of optimizing the powder size, that allows to obtain multi-layer titanium matrix composites reinforced by TiB with well-balanced mechanical properties.

Copper alloy-based metal matrix composite (MMCs) reinforced with different combination of WC-W powders were prepared using the spontaneous infiltration process of the loose powders. The density, microstructure, and hardness of the produced composites were characterized. Friction coefficient and wear rate of the samples under different conditions were carried out in order to determine the tribological properties of the copper based composites as a function of different combination of reinforcement mixtures (WC/WC-W). Wear surfaces of the composites were analysed by scanning electron microscopy (SEM). Results show that WC-W powders improve wear resistance of composites significantly. Wear mechanisms were characterized by delamination, micro cracking and abrasive wear.

Review of pulses discharge technologies (PDT), in which pulses electric discharge in liquid is utilized, is given. PDT of processing and obtainment of new materials allows to impact both changes of geometrical size and the structure of objects in order to give it certain mechanical and physical properties. They are used in oil production, instrumentation, mechanical engineering, metallurgy, chemical industry, mining complex, and other.

Development of new alloys has been slowed by the empirical method of trials and errors that absorbs more and more resources and leads to ever smaller results. Solution of this problem is possible through the use of the general principles of the alloys design theory. In this paper, we have proposed to consider cast metal matrix composites as foundry alloys and have developed a methodological approach to selection of alloying and reinforcing components considering the operational conditions for parts of friction units. Application of the proposed approach allows to make reasonable choice of composite alloys components within conditions of various schemes of reinforcing, including exogenously reinforced, endogenously reinforced and complex reinforced alloys.