arXiv subjects

Oleksiy Bystrenko

Publications and source records attributed to Oleksiy Bystrenko.

6 recordsLinked to original sources

arXiv2025

Mechanical properties of B12-based orthorhombic metal carboborides. A first principle study

Structural and mechanical properties of B12-based orthorhombic metal carboborides are studied on the basis of first principle DFT approach. The simulations predict the existence of a new family of phases of the composition MeC2B12 (Me=Mg, Ca, Sr, Sc, Y) with similar structure and space symmetry Imma. It has been found that the predicted phases are thermally (dynamically) stable and have considerably better mechanical properties as compared to the reference compound AlMgB14. The respective calculated isotropic elastic moduli and Vickers hardness are significantly higher (G~ 230-250, E~530-550, and Hv~35-55 GPa). These conclusions were confirmed by direct calculations of shear strength for the above phases, which demonstrated the increase of 30-50% in different directions. The enhanced mechanical characteristics of the MgC2B12 -based phases make them promising for creating novel superhard materials

cond-mat.mtrl-sci↗

arXiv2024

Orthorhombic metal carbide-borides MeC$_2$B$_{12}$ (Me=Mg, Ca, Sr) from first principles: structure, stability and mechanical properties

First principle DFT simulations are employed to study structural and mechanical properties of orthorhombic B12-based metal carbide-borides. The simulations predict the existence of Ca- and Sr- based phases with the structure similar to that of experimentally observed earlier compound MeC$_2$B$_{12}$. Dynamical stability of both phases is demonstrated, and the phase MeC$_2$B$_{12}$ is found to be thermodynamically stable. According to simulations, Ca- and Sr- based phases have significantly enhanced mechanical characteristics, which suggest their potential application as superhard materials. Calculated shear and Young moduli of these phases are nearly 250 and 540 GPa, respectively, and estimated Vickers hardness is 45-55 GPa.

cond-mat.mtrl-sci↗

arXiv2022

Mechanical properties of AlMgB14-related boron carbide structures. A first principle study

We examine the effects produced by replacing B-B interlayer bonds by C-C bonds in AlMgB14-related boron network on its mechanical properties. The elastic constants, Vickers hardness and shear strength are evaluated by means of first principle computer simulations on the basis of density functional theory. The results of simulations suggest a possibility of existence of several orthorhombic boron carbide phases with strongly enhanced mechanical properties with the Young modulus and Vickers hardness being within the range of 550-600 GPa and 43-50 GPa, respectively

cond-mat.mtrl-sci↗

arXiv2016

Computer simulations of the interface zone structure in binary eutectic

Molecular dynamics simulations of the interface structure in binary AgCu eutectic were performed by using the realistic EAM potential. In simulations, we examined such quantities as the time dependence of the total energy in the process of equilibration, the probability distributions, the composition profiles for the components, and the component diffusivities within the interface zone. It is shown that the equilibrium in the solid state associated with the complete phase separation in binary eutectic is accompanied by formation of the steady disordered diffusion zone at the boundary of the crystalline components. At higher temperatures, closer to the eutectic point, the increase in the width of the steady diffusion zone is observed. The particle diffusivities grow therewith to the numbers typical for the liquid phase. Above the eutectic point, the steady zone does not form, instead, the complete contact melting in the system occurs. The results of simulations indicate that during the temperature increase the phenomenon of contact melting is preceded by the similar process spatially localized in the vicinity of the interface.

cond-mat.mtrl-sci↗

arXiv2014

Contact melting and the structure of binary eutectic near the eutectic point

Computer simulations of contact melting and associated interfacial phenomena in binary eutectic systems were performed on the basis of the standard phase-field model with miscibility gap in solid state. It is shown that the model predicts the existence of equilibrium three-phase (solid-liquid-solid) states above the eutectic temperature, which suggest the explanation of the phenomenon of phase separation in liquid eutectic observed in experiments. The results of simulations provide the interpretation for the phenomena of contact melting and formation of diffusion zone observed in the experiments with binary metal-silicon systems.

cond-mat.mtrl-sci↗

arXiv2010

Self-organization of dissipative and coherent vortex structures in non-equilibrium magnetized two-dimensional plasmas

The properties of non-equilibrium magnetized plasmas confined in planar geometry are studied on the basis of the first principle microscopic Langevin dynamics computer simulations. The non-equilibrium state of plasmas is maintained due to the recombination and generation of charges.The intrinsic microscopic structure of non-equilibrium steady-state magnetized plasmas, in particular, the inter-particle correlations and self-organization of vortex structures are examined. The simulations have been performed for a wide range of parameters including strong plasma coupling, high charge recombination and generation rates, and intense magnetic field. As is shown in simulations, the non-equilibrium recombination and generation processes trigger the formation of ordered dissipative or coherent drift vortex states in 2D plasmas with distinctly spatially separated components, which are far from thermal equilibrium. This is evident from the unusual properties of binary distributions and behavior of the Coulomb energy of the system, which turn out to be quite different from the ones typical for the equilibrium state of plasmas under the same conditions.

physics.plasm-ph↗