## 5 Conclusions  
In this review, we have tried to summarize information on the synthesis and properties of carbon-containing structures (nanotubes, nanofibers, graphene), as well as on composite materials with carbon inclusions. We reviewed the existing methods for modeling the hardening of metal matrix composites reinforced with carbon structures (nanotubes) in order to understand the mechanisms of hardening and deformation of such systems. It should be noted that in the traditional synthesis of a composite material, the carbon material used as a dispersed phase must first be synthesized, purified, functionalized, and only then introduced into the matrix. However, even this procedure may not lead to the expected increase in the mechanical properties of the composite due to poor bonding between the carbon substance and the metal. It should be noted that the development of new structural metal reinforced with high-strength dispersed fillers (nanoparticles, nanofibers, tubes) occupies a significant place in the work of researchers. Replacing monolithic traditional materials with composite materials makes it possible to increase the reliability and weight efficiency of structures. Composite materials based on light aluminum alloys reinforced with particles, due to their high antifriction characteristics in combination with low specific gravity and high operating temperatures (up to 0.8-0.9 of the melting temperature of the matrices), are very promising materials. In this regard, at present, along with the traditional direction of the search for new solid substances and materials (the synthesis of solid substances with an equilibrium crystal structure), the synthesis of solid chemical compounds and materials based on their metastable states is attracting more and more attention. To improve the mechanical characteristics of carbon composites, researchers are faced with the need to develop new methods for the synthesis of composites with a uniform distribution of nanotubes over the volume of the matrix and ensuring chemical interaction between the filler and the matrix. CNTs in the hydrating composite act as centers or initiators for the crystallization of hydration products, leading to a change in the micro/nanostructure of the matrix, including the pore structure. The high tendency of nanotubes to form agglomerations containing up to several hundred CNTs creates significant difficulties in their dispersion into the material matrix. To solve this problem and reduce the degree of agglomeration, it is necessary to develop new methods for the functionalization of CNTs. The properties of carbon nanomaterials and the possibility of using them in technological processes are also determined by the structure of their surface layer. In this regard, researchers today face a very difficult task-to develop methods and approaches for directed control of the physicochemical properties of the surface layer of reinforcing carbon nanostructures to improve the mechanical characteristics of composite materials. From the point of view of physical mesomechanics, the design of nanostructured materials will make it possible to obtain new objects with a multilevel organization, which is necessary for a more correct approach to the study of structural transformation at the nanoscale level. The development of new approaches to the formation of composites with two or more reinforcing modifiers is an important trend in modern materials science, which makes it possible to improve a whole range of functional properties and, at the same time, reduce the total cost of the material. The review shows that the combined use of two reinforcing phases (CNT and TiC with a dispersion of 150 nm) makes it possible to neutralize the negative qualities of the reinforcing phase and obtain a composite material based on an aluminum matrix, which has higher strength characteristics while maintaining the plasticity of the composite.