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The behavior of hydrogen molecules in carbon nanopores of different shapes (slit-shaped, cylindrical, and spherical) is investigated using the molecular dynamics method. It is shown that an adsorbed molecular layer with increased density is formed near the nanopore walls, and dynamic equilibrium is established between this layer and the gas in the central region of the nanopore. The distribution of the density of gas molecules over the cross section is found to depend on the size and wall curvature of nanopores: with a reduction in the nanopore size, the density of the adsorbate increases more rapidly in spherical nanopores, whose walls are characterized by greater mean curvature.

The results of studying the plastic deformation of the product of high-temperature synthesis on the grain structure, the strength, and the ductility of the intermetallic compound Ni3Al are presented. Plastic deformation forms a multimodal grain structure in Ni3Al. The multimodal grain structure contains of submicron multigrains. The volume fraction of multigrains increases and the strength and the ductility of synthesized Ni3Al increase with the strain.

Regularities of changes in chemical composition and microstructure of titanium nickelide upon high-dose ion-beam implantation of silicon into its surface were studied. It was shown that irradiation of a TiNi alloy with silicon ion beams results in formation of a surface oxide layer about six times thicker than that at the surface of the unirradiated alloy. The surface oxide layer of the ion-beam-modified alloy has an oxygen concentration which is ∼20% greater than that of the unmodified TiNi surface layer and lacks nickel, whose concentration is near zero to a sample depth of about 20 nm. Investigation of the near-surface region beneath the irradiated surface of TiNi samples by electron backscatter diffraction revealed that, under the action of a silicon ion beam, the near-surface region of individual B2-phase grains rising to the surface is fragmented with formation of a grain-subgrain structure with fragment (grain) sizes decreased down to 5 to 15 μm. It was suggested that grain orientation influences the observed effect.

The author formulates the principles of controlling the mechanical properties of materials through the targeted formation of multilevel (multimodal) structures. The potentialities of the proposed approach are illustrated by examples of developing high-performance materials and by solving various interdisciplinary problems.

The results of the investigation of the proliferation effect on a mesenchymal stem cell (MSC) culture and the estimates on cytotoxicity of surfaces of titanium nickelide specimens prepared using special mechanical and electrochemical methods and characterized by different morphology and roughness are presented. The specimens of the alloy based on titanium nickelide are shown not to exert any toxic action on the MSCs of rats. When cultivated in the presence of the tested materials or being on their surfaces, MSCs preserved their viability, adhesive and morphological properties, and the ability for in vitro proliferation. This was confirmed by the following methods: cell counting in a Goryaev chamber, MTT, flow cytometry, and light and fluorescent microscopy. It was revealed that the proliferation processes are weakly pronounced on the surface of TH1(B) specimens whose C10–11 class roughness was achieved by multistage mechanical grinding to “high luster” and subsequent electrolytic grinding. On the contrary, the C7 class roughness of the TH1(A) specimen surfaces achieved by chemical etching and subsequent electrolytic grinding is more optimal for MSC proliferation.

A sorption material based on acetylcellulose microfibers, modified by nanostructural aluminum oxyhydroxide, is described, and its microbiological activity is studied. The data on the adsorption efficiency of microorganisms of different morphology and size and bacterial endotoxin (BE) from aqueous media are presented.

Products formed at various stages of the hydrolysis of aluminum nanopowder prepared by electrical explosion in the atmosphere of nitrogen were isolated and characterized. Particles formed in hydrolysis were shown to have the morphology of nanosheets 5–10 nm thick agglomerated into 0.5–3.0 μm volume structures. The phase composition of hydrolysis products was determined.

The mechanical behavior of porous ceramic materials with a stochastic structure of their pore space is numerically studied during shear loading. The calculations are performed by the mobile cellular automaton method. A procedure is proposed for a numerical description of the internal structure of such materials using the dispersion of the pore distribution in layers that are parallel to the loading direction in a sample. The dependence of the macroscopic elastic properties of porous media on their internal structure is analyzed. Samples with spherical pores and pores extended along the loading direction exhibit a correlation between their average shear modulus and the dispersion of a pore distribution. Thus, the results obtained indicate that the shear modulus of such media is a structure-sensitive property. The proposed approach can be applied to compare the elastic properties of samples using data on their pore structure.

The spaced monitoring system developed for relative displacements in a block-faulted geomedium enables the central time-lapse survey of movement of lengthy and spaced discontinuities in a wide range of temperatures and weather environment. The communication between the monitoring system units is wireless.

Investigation of real geological media faces significant difficulties related to the scale of objects (e.g., the length of fractures ranges from tens to thousands of kilometers) and significant durations of geological processes (long-term observations are needed to obtain reliable information about peculiarities of the response of fractures to forcing). Strains are accumulated over tens and even hundreds of years [1‐3]. Therefore, physical modeling using simplified and smaller-scale block schemes is a promising field in the study of tectonic processes in the Earth’s crust. The rheological characteristics, structural pattern, and forcing dynamics in such schemes can be considered similar to those in the Earth’s crust [4‐5]. The present paper is dedicated to study of the implication of the fracture-block system of ice cover in Lake Baikal and dynamics of its loading as an object for modeling geotectonic and seismogeological processes in the lithosphere. Investigations and observations were carried out during expeditions of the Siberian Division of the Russian Academy of Sciences in 2005‐2006 with the participation of scientists from

An approach to simulating exothermic chemical reactions based on the concept of cellular automata is described. The validity of the approach is analyzed using the results of simulating the propagation of the reaction front during self-propagating high-temperature synthesis in the Ni-Al system. Good agreement is obtained between simulated and experimental dependences of the propagation velocity of the front and the maximum combustion temperature on the initial heating temperature of the powder mixture. It is concluded that a correct description of the effect of porosity on the course of the exothermic reaction requires explicit allowance for the reaction kinetics, in particular, the spreading of the liquid phase.

A molecular-dynamic study of nucleation of structural defects in materials with an initially perfect crystal lattice by thermal fluctuations under high strain rates is performed. It is shown that thermal fluctuations can generate structural defects. There exists some threshold value of strain at which abrupt growth of regions with local structural changes is observed.

A constitutional function for a bistable cellular automaton is presented which is universal for numerous processes. The bistable cellular automaton formalism was used to describe the propagation of a combustion (switching) wave in a chemically active medium. The calculated dependence of front velocity on the initial state and properties of a system was used to describe the synthesis of Ni3Al in a powder mixture. The calculated results were in good agreement with experimental data. The relationships obtained permit calculation of the important technical parameters for synthesis in the combustion regime.

The features of perturbation propagation in a copper crystal grain under local high-energy loading conditions were studied. The process was studied by method of molecular dynamics using multiparticle model potentials calculated within the framework of the embedded atom approximation. It is shown that a nonlinear solitary pulse is formed in the crystal, which is capable (in contrast to the case of a linear perturbation) of transferring the energy at a high density over relatively large distances. The energy transfer range depends both on the area and on the rate of local loading.

The influence of anisotropic dynamic loading on the character of plastic deformation and fracture processes in a crystallite near the free surface was studied by methods of molecular dynamics. It was established that there are threshold deformation levels determining the opening of a seeding crack (notch) and the subsequent crack stop. The simulation results show that loading in the [100] direction leads to the crack stop due to the formation of a disordered material region at the crack tip.

A new approach to layer-by-layer film deposition is developed based on the data of molecular dynamics modeling. The proposed deposition method makes use of a nonlinear pulse interaction with a free material (source) surface. It is shown that, provided the pulse amplitude is sufficiently large, an atomic plane is detached from the surface. Impinging on a target (substrate), the detached plane forms a monolayer coating. Combining various source materials, it is possible to obtain multilayer films with complicated compositions and structures.

The spalling fracture in a copper crystallite with a specific intergrain boundary under pulsed loading is modeled numerically. It is found that the grain boundary changes the parameters of nonlinear waves generated by loading and significantly affects the character of the spalling fracture.

It is shown within the framework of molecular-dynamic modeling that the interaction of a nonlinear pulse with a free surface can result in the separation of an atomic plane. According to the results obtained upon colliding with the target, the separated fragments can form a multilayer coating. This has formed the basis of the proposed approach to the level-by-level application of thin coatings. It is shown that the change in the number of pulses and in the time for which they reach the surface of a “source” can significantly change the structure and composition of the coating at the target.

The process of pulse-train-induced cleavage fracture in a copper crystal with grain boundary was studied by methods of computer simulation. It is demonstrated that trains of isolated compression pulses induced in the material favor the tendency to fracture propagation along the grain boundary.

Impurity behaviour (both thermodynamic and mechanic properties) are investigated under pressure and shear application. The conditions are found of shear instability occurrence — the critical temperature θc and critical shear stress τc. θc decreases with shear stresses application and τc decreases with temperature growth. The used Green's functions method could be applied for the different cases of atomic Hamiltonians and for the different types of mechanical loading. Das Storstellenverhalten (sowohl thermodynamische als auch mechanische Eigenschaften) unter Druck und Scherung wird untersucht. Bedingungen fur das Auftreten von Scherungsinstabilitat, die kritische Temperatur θc und die kritische Scherspannung τc werden gefunden. θc nimmt mit der Scherspannung ab und τc nimmt mit steigender Temperatur ab. Die benutzte Methode der Greenschen Funktionen last sich fur verschiedene Falle atomarer Hamiltonians und fur die verschiedenen Arten der mechanischen Belastung anwenden.

The molecular-dynamic modeling of the behavior of a three-dimensional crystallite that contains a specific-type grain boundary under shear loading is performed. It is found that the accommodation of displacements of the material grains can be realized owing to structural changes in the intergrain boundaries. The crystal-like structure of the grains can be restored after the external action terminates. The results obtained give deeper insight into the nature of the structural response of the material under mechanical loading at the atomic level.

Generation of nonlinear solitary waves in a system described by many-body interatomic interaction potentials is modeled for the first time. The behavior of a free surface of Ni and Al crystallites under high-rate loading is studied. Calculations show that solitary pulses produced by high-rate loading increase in amplitude by about a factor of 1.5 at the free surface of Ni and remain almost unchanged at the free surface of Al. The nature of this effect is associated with differences in the skeleton-skeleton interaction of Ni and Al.

The nonlinear response of a material under a high-energy process acting on groups of atoms or individual atoms of a free surface is studied. The dissipation of the energy transferred by soliton-like pulses at structural defects, such as regions with high vacancy density, grain boundaries, and the free surface, is investigated. A method of describing the “longrange action” during ion implantation in metallic materials is proposed.

Molecular dynamics techniques are used to show that heat can be transferred ballistically in threedimensional crystalline materials at temperatures on the order of Debye temperatures.

An aluminum crystallite containing 500 atoms with an effective dual interaction potential computed within the framework of the theory of pseudopotential was modeled by using the method of molecular dynamics. The binding energies of complexes from impurity magnesium atoms and vacancies as well as the migration activation energies (MA) of the magnesium and aluminum atoms were computed under shear strain conditions. It is shown that shear strain results in separating out of the individual directions energetically most favorable for the formation of complexes of impurity atoms and vacancies, as well as the directions in which the MA energy values are lowered.

A model is proposed that takes account of features of the material state under a pulse effect. The characteristic inhomogeneous states for an unstable medium are analyzed. Their correspondence with experimentally detected effects is noted.

The behavior of the boundaries of grains of special type in the material during high-rate shear loading was studied numerically. Two paths of evolution of the simulated system were shown: an intense rearrangement of the intergrain boundary occurs at high deformation rates and the process of relaxation of the energy supplied to the material is accomplished by displacing the boundary as the intensity of loading is decreased. The calculations showed that the intergrain boundary can be shifted with an abnormally fast speed. Vortex collective motion of the atoms causes high velocities of displacement of the grain boundaries.

An analysis is made of some characteristic features of the interaction between solitary pulses (soliton-like waves) generated under high-velocity loading and structural defects in an Al crystallite. Calculations are made using the molecular dynamics method. It is shown that in materials undergoing shear loading and those undergoing compression different types of solitary pulses are formed which interact differently with regions containing structural defects. The waves formed under compression have a higher propagation velocity in the material, and their profile recovers fairly rapidly after propagating through defect zones. These phenomena are of interest for developing methods of nondestructive testing.

The characteristics of the transient process of relaxation to steady-state deformation in solids are investigated theoretically. Various loading regimes are modeled by the method of mobile cellular automata. It is shown that the stressed state in a material is highly inhomogeneous in the relaxation stage; this property, in turn, can produce stable structures in the velocity field of the material particles and influence the evolution of deformation in later stages.

The behavior of a medium in which hydrodynamic behavior is possible for some of its atoms is analyzed. A model that permits description of the resulting hydrodynamic mode is proposed. Conditions under which its occurrence in a solid becomes possible are investigated.

A molecular dynamics method was used to study the interaction of isolated compression pulses with the (100) and (110) free surface in a copper monocrystallite. It is shown that this may be accompanied by cleavage fracture. Parameters of compression pulses which lead to cleavage processes are determined.

Based on the method of molecular dynamics, we investigated the special features of the passage of soliton-like waves, initiated by high-speed loading, through regions with a low atomic density. It is shown that the shape of these waves is mainly determined by the structure of a material region in which they propagate. The decrease in the amplitude of solitary waves is shown to be determined by the defect concentration. This effect is of interest from the viewpoint of developing the methods of monitoring the microdamage build-up in materials.

A computer simulation is made of the grain boundary behavior in an aluminum sample under conditions of fast shear loading. The calculations are made using a molecular dynamics method and pseudopotential theory. It is observed that under these loading conditions, the grain boundaries may undergo displacement at an anomalously high speed, even exceeding the rate of the applied shear. The atomic mechanisms responsible for this effect are investigated.

The influence of deviations in the substance density from the equilibrium magnitude on the phase equilibria is studied in metals and alloys. Such deviations can be associated with both the external effects and the features of the substance structure. A technique for constructing phase diagrams of the temperature-concentration-atomic-density type for alloys is proposed. The calculations involved in constructing such a phase diagram for the K-Rb system are carried out. The calculated results are in good agreement with the experimental results available.

Expressions are obtained for calculating the binding energy of an arbitrary complex formed from impurity atoms and vacancies. Calculations are made for various complexes formed from magnesium and zinc impurity atoms and vacancies in aluminum. The results obtained are used to study the role of vacancies in the formation of Guinier-Preston zones. The need to allow for the lattice relaxation is demonstrated.

An examination of the dependence of the free energy of liquid and solid phases on volume in a one-component substance is used as a basis to prove that it is possible to use a conoid law to construct phase diagrams of a new type: temperature-density of the substance (T-n). A similar approach can be applied in a more complicated case: to multicomponent systems and to phases of an arbitrary nature. An analysis is made of nonequilibrium T-n diagrams for Mg constructed in the temperature range from 200 to 1200‡K by the method indicated. The conditions necessary for Mg to change from equilibrium states to the region in which the liquid and solid phases coexist are determined.

Atomic structure changes of a crystal induced by shock waves are studied by molecular dynamic method. α-Fe crystallites are used for simulation having a rectangular area in the (110) plane and containing about 104 atoms. The radial distribution function of atoms is shown to lose its discrete form, typical of a crystal and to become continuous when the shock wave planar front is distorted. Microfragmentation in the corresponding areas of a crystal is shown at the same time to be the result of the shock wave distortion with a planar front. [Russian Text Ignored].

We use a pseudopotential and thermodynamic perturbation theory to study the thermodynamic characteristics of metallic Mg and Zn melts. A system of solid spheres is selected, to be the ground state. Our calculations of the melting temperature, entropy, and volume are in good agreement with experiment, and the calculated results are insensitive to the choice of pseudopotential. As the temperature is lowered the diameter of the solid spheres and the packing density increase. In addition, there is a marked decrease in the melt's self diffusion coefficient, reflecting the possibility of forming an amorphous structure.

This study has considered the two most important aspects of thermodynamic description of a real crystal. Until now, each of these has been analyzed in the literature only in isolation from the other. In the general case both factors must be considered within a unified approach. The calculation technique would proceed as follows: 1) The equilibrium atomic volume (Ω0) at fixed temperature is calculated within the framework of thermodynamic perturbation theory; 2) for known (Ω0) and atomic oscillation frequency values, which “correct” the pair interaction potential by means of the Debye-Waller factor, the molecular dynamics method is used to calculate the real crystal structure and frequency distribution; 3) substitution of these data in thermodynamic perturbation theory equations completes the iterative procedure of thermodynamic Gibbs potential calculation with consideration of the real crystal structure.

Failure is described as the evolution of a kinetic system, and the conditions are considered for the formation of a stable structure arising from damage elements. A parabolic-type equation system describes the kinetics and is constructed on the basis of interaction between damage elements of two types, which are identified as local excited states interacting in accordance with the rules of formal chemical kinetics. The solutions staisfy the general laws of solid-state failure.

A model is proposed for the rough surface of a solid based on the particle method. Although the particle size is selected arbitrarily in this study, the evolution of the actual area of contact and the change in stress at the points of contact show fairly good agreement with concepts derived from experimental investigations. The experiments show that as two surfaces converge, the pressure at the contacts is considerably higher than the nominal value, and this leads to plastic deformation of the surface layers much greater than the bulk deformation. The model clearly shows the controlling factors and how the stressed state of the surface layer is formed. The model can be used to analyze interaction between surfaces, not only for the stationary case, but also when these undergo relative displacement.