PSI - Issue 65

E.G. Zemtsova et al. / Procedia Structural Integrity 65 (2024) 317–323

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E.G. Zemtsova et al. / Structural Integrity Procedia 00 (2024) 000–000

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The manufactured samples with the Al/nano TiC reinforcing phase showed strength characteristics 1.5 times higher than those with micron reinforcing carbide phases, while the plasticity remained at the level of pure Al. The relationship between the size of the reinforcing phase and the mechanical properties of the Al-based composite obtained by casting was also shown. Al-based composites obtained by injection molding, for which a reinforcing phase with surface carbide nanostructures is used, in addition to a higher tensile strength, demonstrate a more plastic fracture pattern characteristic of dispersed hardening of materials. With an increase in the volume of reinforcement of the composite with carbide nanostructures from 1 to 5%, the high plasticity of the material remains comparable to a sample made of pure Al (Fig. 4).

Fig. 4. Deformation curves of Al matrix composites

The improvement in the strength characteristics of materials reinforced with pure carbide phases, compared with pure Al, is due to the presence of structural inhomogeneities that create additional resistance to the movement of dislocations. These hardening processes are described within the framework of the Orovan mechanism. In addition, with a decrease in the size of the reinforcement particle, additional hardening mechanisms are becoming increasingly important. The semi-coherent and coherent behavior of the interface of non-structured phases and the concentration of these reinforcing defects in the matrix will also allow the mechanisms described in the framework of the Motto and Nabarro mechanism to be implemented for particles enveloped by dislocations. Due to the small size of the defects, against the background of the emergence of new dislocations, relaxation of structures is also observed due to the slippage of dislocations relative to strengthening particles. Due to this, the plasticity of the material is preserved and the load applied to the sample spreads evenly over a larger volume of the material matrix, forming additional hardening zones when sliding. The strengthening effect of these hardening mechanisms is well observed during the transition from micron reinforcement particles to titanium carbide nanostructures. In the process of work, a technique was developed for production of a composite material with a uniform distribution of dispersed phase particles in the aluminum matrix bulk obtained by casting. The manufactured samples with an Al/nano-TiC reinforcing phase (less than 4 nm) showed strength characteristics 1.5 times higher than composites with a micron reinforcing carbide phase, and 2 times higher than Al samples obtained by injection molding. The plasticity of the samples remains at the level of pure Al for all obtained samples of composite materials, in which the dispersed reinforcing phase is TiC nanoparticles (less than 4 nm) obtained during chemical assembly on the surface of aluminum particles. The relationship between the size of the 4. Conclusion