# Section of Theory and computer simulations in materials science and condensed matter physics

#### Effect of external pressure on the hydrogen storage capacity of a graphene flake: molecular dynamics

Gravimetric density as the function of exposure time at two temperatures and pressure. The inset shows the initial structure of a crumpled graphene flake (gray atoms) in a hydrogen atmosphere (blue atoms).

N.G. Apkadirova, K.A. Krylova, J.A. Baimova

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*Article*#### Modeling the structure and electronic properties of new polymorphic L4-8 hydroxygraphene varieties

Modeling of the structure and electronic properties was carried out from the first principles for the polymorphic varieties of graphene with adsorbed hydroxyl groups (hydroxygraphene), where basic graphene layer structure consisted exclusively of 4-8 paired topological defects.

M.E. Belenkov, V.A. Greshnyakov, V.M. Chernov

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*Article*#### Experimental and theoretical study of the conditions for the formation of carbon nanostructures in an arc discharge in helium, argon and nitrogen

The synthesized material mainly consists of amorphous carbon with graphite crystallites, the maximum amount of which is formed during an arc discharge in nitrogen.

S.Z. Sakhapov, V.A. Andryushchenko, E.V. Boyko, M.S. Skirda, D.V. Smovzh

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*Article*#### Influence of the thickness of a nonmagnetic layer on the coupled dynamics of magnetic vortices in a spin-transfer nanooscillator

Dependence of the critical currents on the thickness of the non-magnetic layer in a spin-transfer nanoscillator.

V.V. Mukhamadeeva, S.V. Stepanov, K.A. Zvezdin, E.G. Ekomasov

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*Article*#### Simulation of deformation and growth during surfacing of aluminum bronze nanograins

Investigation by simulation methods of the development of defects in a polycrystal of aluminum bronze and their stability when interacting with a melt drop during surfacing.

A.Y. Nikonov, D.V. Lychagin, A.A. Bibko, O.S. Novitskaya

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*Article*#### The adsorption modeling of bisphenol A derivatives on the surface of carbon materials

Bisphenol A derivatives on the surface of carbon materials.

S.A. Sozykin, E.V. Bartashevich

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*Article*#### Interaction of an edge dislocation with a 〈110〉 tilt boundary in nickel: molecular dynamics simulation

The interaction of a lattice edge dislocation with a 〈110〉 tilt boundary in nickel was studied by the molecular dynamics method in the case when the dislocation glide plane is parallel to the grain tilt axis

G.M. Poletaev, Y.V. Bebikhov, A.S. Semenov, R.Y. Rakitin

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*Article*#### Sensory properties of carbon nanotubes containing impurity boron atoms

The figure shows a model used in a model experiment to study the interaction of modified boron-containing nanotubes with a carbon dioxide molecule

S.V. Boroznin, I.V. Zaporotskova

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*Article*#### Improving the accuracy of finite element modeling of superplastic forming processes

Unlike of our previous report the method suggested takes into account consideration the initial stage of superplastic forming, when the pressure of the inert gas changes from the initial zero level to a pre-given constant value. It is shown that such kind refinement enables one to improve considerably the accuracy of calculating the value of the strain rate sensitivity index, m, and, as a result, to provide more accurate finite element description of the superplastic forming processes.

O.P. Tulupova, C. Gumerova, V.R. Ganieva, A.A. Kruglov, F.U. Enikeev

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*Article*#### First-principles calculation of possible carbon positions over cementite lattice

Structures with all C atoms in DPS positions and one or all C atoms in DOS position are mechanically unstable, in other cases, the C atom remained on NOS or DPS position with increased energy

A.V. Verkhovykh, K.Y. Okishev, A.A. Mirzoev, N.S. Dyuryagina

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*Article*#### Graphene nanoflakes and fullerenes doped with aluminum: features of Al-C interaction and adsorption characteristics of carbon shell

The Al-C interaction in graphene-coated aluminum nanoparticle and Al@C60 metallofullerene is studied with DFT approach.

K.P. Katin, S. Kaya, M.M. Maslov

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*Article*#### Phase transitions in an ordered 2D array of cubic nanoparticles

Array of cubic nanoparticles.

S.V. Belim, O.V. Lyakh

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*Article*#### Search for stable skyrmion lattices at the ground state in a multiferroic nanofilm using artificial neural networks

This work is devoted to the search for such values of the interaction parameters and the intensity of external fields in a three-layer multiferroic film , at which nontrivial topological magnetic structures are stable in the ground state. To reduce the computational complexity of searching in the parametric space, we use the apparatus of artificial neural networks

A.G. Nugumanov, I.F. Sharafullin

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*Article*#### Molecular dynamics study of the influence of free volume and orientation of the crystallization front on its velocity in nickel

The influence of free volume and orientation of the crystallization front relative to the growing crystal on the front movement velocity in nickel was studied by the method of molecular dynamics

G.M. Poletaev, I.V. Karakulova, D.V. Novoselova, R.Y. Rakitin

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*Article*#### The structure and properties of a carbon nanotube (7, 7) with a vacancy defect

Adsorption of lithium on a carbon nanotube with a vacancy defect.

S.A. Sozykin, V.П. Beskachko

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*Article*#### Effect of hydrogenation of carbon atom on its deposition on graphene

It was found by molecular dynamics that the deposition of hydrogenated and dehydrogenated carbon atoms on defect-free graphene depends on the degree of hydrogenation of carbon atoms.

K.I. Jabborov, A.N. Ulukmuradov, I.D. Yadgarov, N.I. Ibrokhimov

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*Article*#### Molecular dynamics investigation of atomic mixing and mechanical properties of Al / Ti interface

Molecular dynamics simulation is utilized to analyze the role of applied compressive and shear strain on the mechanical performances of Al/Ti composite. Mixing of atoms near the interface between Al and Ti during deformation is analysed.

P.V. Polyakova, S.A. Shcherbinin, J.A. Baimova

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*Article*#### On a unique constitutive equation for steady state isotropic optimal structural superplastic deformation in all classes of materials

Steady state isotropic optimal superplastic deformation in 175 materials systems of different classes studied can be represented by the equation 8 in the main text

K. R. Harisankar, S. Sripathi, K.A. Padmanabhan

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*Article*#### Modeling of the process of superplastic forming of hemispherical shells from blanks of different profiles

Distribution of the third main deformation the hemispherical shell from a conical blank

G.R. Murzina, V.R. Ganieva, A.A. Kruglov, F.U. Enikeev

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*Article*#### Modeling the crystallographic texture of of ferritic/martensitic steel during rolling: the level and anisotropy of strength properties

Values of Lankford coefficients for various thickness reduction at rolling UFG steel.

V.D. Sitdikov, G.F. Sitdikova, E.D. Khafizova, R.K. Islamgaliev

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*Article*#### Structure and properties of a chiral polymorph of diamond with a crystal lattice of the SA3 type

A theoretical study of the structure and properties of a chiral SA3 diamond polymorph has been performed. The chiral SA3 phase can be obtained by polymerization of nanotubes (5,4). The unambiguous identification of this phase is possible using X-ray diffraction analysis, X-ray absorption and Raman spectroscopy.

V.A. Greshnyakov, E.A. Belenkov

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*Article*#### The role of a shear planar mesodefect in the nucleation of a crack at a grain junction due to athermal grain boundary sliding

Athermal grain boundary sliding due to the motion of virtual dislocations of planar shear mesodefect essentially facilitates microcracks nucleation.

V.N. Perevezentsev, S.V. Kirikov, J.V. Svirina

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*Article*#### Self-diffusion in melts of Ni-Al and Ti-Al systems: molecular dynamics study

Self-diffusion parameters for melts of Ni-Al and Ti-Al systems, depending on the concentration of the components, have found by the method of molecular dynamics

G.M. Poletaev, Y.V. Bebikhov, A.S. Semenov, M.D. Starostenkov

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*Article*#### Comparison of traditional and fullerene-based adsorbents for extraction of 1,4‑dioxane and 2‑methyl-1,3‑dioxolane from milk

Quantum theory and analysis of chemical reactivity were applied to choose suitable adsorbents that ensure efficient solid-phase microextraction of dioxane and dioxalane from milk. It is shown that carbon nanostructures possess some advantages over primary and secondary amines.

A.I. Kochaev, R. Razavi, S. Kaya, M. Mogaddam, N. Altunay, M. Nemati, K.P. Katin, K.S. Grishakov, A.I. Podlivaev, M.M. Maslov

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*Article*#### A new method for determining energetically favorable landing sites of carboxyl groups during the functionalization of graphene nanomesh

Method for determining energetically favorable landing sites of carboxyl groups during functionalization of graphene nanomesh by atomic charge distribution

O.E. Glukhova, P.V. Barkov

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*Article*#### Molecular dynamic analysis of energy transport in a Pt3Al crystal under the impact in the spectrum gap frequency

The process of formation of a solitary wave under external harmonic action at the frequencies of the forbidden zone of the crystal.

P.V. Zakharov, S.V. Dmitriev, E.A. Korznikova

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*Article*#### Room temperature hydrogen storage in defective single-walled carbon nanotubes: a molecular dynamics study

A defective nanotube containing 5 and 8 -membered rings shows the highest adsorption capacity of 1.82 %wt/wt which is higher than the pristine nanotube and the adsorption capacity increases with %defect.

M. Garg, S. Ghosh, V. Padmanabhan

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*Article*#### Simulation of isothermal reversible strain in the Ti40.7Hf9.5Ni44.8Cu5 alloy using a microstructural model

Modification of a microstructural model allows describing the strain variation on isothermal holding and predicting conditions (temperature and stress), at which the maximum of isothermal strain is attained.

E.S. Demidova, F.S. Belyaev, S.P. Belyaev, N.N. Resnina, A.E. Volkov

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*Article*#### Computer simulation of pressure welding of heat resistant heterophase nickel-based superalloys specimens through an interlayer

Computer modeling of the pressure welding process of cylindrical workpieces from heterophase nickel-based superalloys through an interlayer was carried out.Two combinations of materials to be welded were considered: I – cylinders of the same wrought EP975 nickel-based superalloys in the initial coarse-grained state were welded through an interlayer of EP975 with a fine-grained microstructure; II – cylinders of different kinds nickel-based alloys, including wrought alloy EP975 in a coarse-grained state and intermetallic alloy VKNA-25 with a single-crystal structure, were welded through an interlayer of EP975 alloy with a fine-grained microstructure of the microduplex type.
The distribution of equivalent, axial, radial, circumferential and shear components of stress and strain in the samples have been investigated. Analysis of the simulation results allows us to conclude that, in comparison to welding of the same name materials, when welding of different kinds materials, the radial, axial and circumferential stresses values increase. The maximum values area of shear stresses in the region of contact between the cylinders and the interlayer also increases. This factors combination allows us to conclude about more favorable pressure welding conditions for welding of different kinds alloys in comparison with the same name materials.

A.K. Akhunova, V.A. Valitov, E.V. Galieva

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*Article*#### Melting temperature of Ti and TiAl nanoparticles in vacuum and in Al matrix depending on their diameter: molecular dynamics study

The dependence of the melting temperature of Ti and TiAl nanoparticles on their diameter in vacuum and in Al matrix is studied by the method of molecular dynamics

G.M. Poletaev, A.A. Sitnikov, V.Y. Filimonov

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*Article*#### Model of the hysteresis loop of soft-magnetic amorphous alloys with the usage of a modified linear fractional function

The resulting model of the hysteresis loop provides a sufficiently high-quality approximation of the values of magnetic induction with an error not exceeding the measurement error, and its application doesn't require complex calculations or the development of a special computer program.

V.Y. Vvedenskiy, E.N. Tokmakova

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*Article*#### Study the exchange bias field in ferromagnetic film on antiferromagnetic substrate

Displacement of the ferromagnetic film hysteresis loop when the system is heated.

S.V. Belim

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*Article*#### Computer simulation of a composite based on a monolayer of pyrolyzed polyacrylonitrile containing paired metal atoms Cu, Co, Ni, Fe

In this work, models of a monolayer of pyrolyzed polyacrylonitrile containing pairs of metal atoms have been created. A complete optimization of the cluster geometry was carried out using the DFT method.

I.V. Zaporotskova, D.P. Radchenko, L.V. Kozhitov, S.V. Boroznin, N.P. Boroznina

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*Article*#### Numerical simulation of magnetic discrete breathers in a Heisenberg spin chain with antisymmetric exchange

Spatially localized breather excitations are investigated for the model of a discrete Heisenberg spin chain, which includes an antisymmetric exchange interaction and single-ion anisotropy of the easy-plane type. Taking into account the antisymmetric exchange leads to the excitation of only antisymmetric magnetic discrete breathers.

I.G. Bostrem, V.E. Sinitsyn, A.S. Ovchinnikov, M.I. Fakhretdinov, E.G. Ekomasov

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*Article*#### The thermal effect of deformation during the ECAP processing of the Cu-0.6Cr alloy

Investigation of deformation heating during ECAP using the Deform-3D complex for mathematical modeling.

D.A. Aksenov, R.N. Asfandiyarov, G.I. Raab, M.P. Baryshnikov

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*Article*#### Molecular dynamics simulation of high-speed loading of 2D boron nitride

Schematic representation of boron nitride composed of nitrogen (red) and boron (blue) atoms.

I.A. Shepelev, S.V. Dmitriev, E.A. Korznikova

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*Article*#### Analysis of the conditions for the existence of stable microcracks in an elastic stress field from a rotational-shear mesodefect

The dependences of the critical value of the disclinations dipole strength on the mesodefect length obtained at various values of the strength of the planar mesodefect are shown. The regions of parameters for which stable cracks can exist for each of the given values of the strength of the planar mesodefect lie above the corresponding curves.

S.V. Kirikov, V.N. Perevezentsev

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*Article*#### Investigation and modeling of the effect of pre-deformation of austenite on the kinetics of ferritic transformation

Based on the obtained experimental data a physically motivated model is formulated for the ferritic transformation with allowance for the effects of deformation and concurrent recovery of austenite. The model is first to evaluate variation of nucleation barriers owing to the hydrostatic component of internal stresses at austenite grain boundaries.

A.A. Vasilyev, D.F. Sokolov, S.F. Sokolov

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*Article*#### Analytical evaluation of magnetic pulse deformation of TiNi alloy

Schematic of the magnetic pulse installation for tensile testing.

E.S. Ostropiko, S.I. Krivosheev, S.G. Magazinov

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*Article*#### Kinetics of formation and structural rebuilding crystalline films

Illustration of the temperature dependence of the activation threshold for desorption at low levels of surface filling with deposited atoms: the presence of two curves indicates a rearrangement of the surface structure.

I.G. Popova, A.V. Blagin, L.V. Blagina, V.I. Lebedev

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*Article*#### Zero misorientation interfaces in graphene

Zero misorientation interfaces (ZMIs) in graphene and their disclination schemes.
Minimum disclination strength is ω = π/3.

M.A. Rozhkov, N.D. Abramenko, A.L. Kolesnikova, A.E. Romanov

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*Article*#### Theoretical study of the stability and formation methods of layer diamond-like nanostructures

Structure formation of diamond-like bilayers.

V.A. Greshnyakov, E.A. Belenkov

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*Article*#### The role of grain boundaries and their triple junctions in strengthening and softening of nanocrystalline ceramics

The transition from a direct to an inverse Hall-Petch dependence for nanocrystalline ceramics is related to an increase in the number density of triple junctions and dislocation emission from these junctions.

A.G. Sheinerman, M.Y. Gutkin

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*Article*#### On the common topological conditions for shear-coupled twin boundary migration in bcc and hcp metals

Despite different atomic structures and degrees of symmetry of bcc and hcp crystals, the topological aspects of the processes of growth and shrinkage of {112}bcc and {10-12}hcp deformation twins are equivalent.

A. Serra, N. Kvashin, N. Anento

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*Article*#### Migration mechanism of <110> tilt boundaries in nickel

The features and migration mechanism of tilt boundaries with the misorientation axis <110> in an fcc crystal using nickel as an example are studied by the method of molecular dynamics

G.M. Poletaev, I.V. Zorya, R.Y. Rakitin

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*Article*#### The concept of quasineutrons and the synthesis of zinc from the extraction of a part of the material of copper electrodes during electric current discharges in an aqueous solution of NaCl

Energy spectrum of the main elements in the material:
a) electrodes (technical copper); b) particles of sediment powder containing zinc (particle 2 in Table 1)

M.P. Kashchenko, V.F. Balakirev, N.M. Kashchenko, M.B. Smirnov , Y.L. Chepelev, V.V. Ilyushin, N.V. Nikolaeva, V.G. Pushin

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*Article*#### To the relation between the orientation of the pore channels and the mechanical properties of porous NiTi shape memory alloy

The functional and mechanical properties of porous shape memory alloys are determined by the phase transformations and the features of the pore structure. The modeling results aimed at clarifying the influence of these factors on the behavior of porous NiTi.

E.N. Iaparova, A.E. Volkov, M.E. Evard

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*Article*#### Introduction to the theory of bushes of nonlinear normal modes for studying large-amplitude atomic vibrations in systems with discrete symmetry

The group-theoretical classification of atomic vibrations in molecular and crystal structures is discussed. Wigner’s classification, which is valid for small-amplitude oscillations, is generalized to the case of oscillations with arbitrary amplitudes. An elementary introduction to the theory of bushes of nonlinear normal modes is given.

G.M. Chechin, D.S. Ryabov

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*Review*#### The effect of the occurrence of a magnetic field of a current loop in hybrid graphene / C60 carbon systems

The conditions for the appearance of a circular current during the ordered motion of the C60 fullerene on graphene with a defect in the form of local hydrogenation of the atomic network are found. The defect should form a bowl-shaped well in the energy surface of interaction of C60 with graphene, along the edges of which the fullerene will make a circular motion.

O.E. Glukhova, V.V. Mitrofanov, M.M. Slepchenkov

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*Article*#### Simulation of metal-graphene composites by molecular dynamics: a review

Pressure-strain curves for Ni-graphene systems under hydrostatic tension at 0 K and corresponding snapshots of composite at different strain. Ni atoms are shown by blue and C atoms are shown by red.

L.R. Safina, J.A. Baimova, K.A. Krylova, R.T. Murzaev, R.R. Mulyukov

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*Review*