arXiv subjects

A. I. Karasevskii

Publications and source records attributed to A. I. Karasevskii.

6 recordsLinked to original sources

arXiv2025

Thermodiffusion mechanism for the formation of an amorphous phase during the quenching of a metal melt

A theoretical model of the formation of an amorphous phase during the quenching of a metallic melt is proposed. It has been shown that the appearance of a significant temperature gradient during the quenching of a metallic melt leads to thermodiffusion of defects and their outflow from the melt volume, which manifests itself in a significant reduction in the number of free spaces for the diffusion transfer of the atoms of the melt. Due to the thermodiffusion process, a significant restructuring of the microstructure of the medium occurs, which leads to a significant increase in viscosity, a decrease in the diffusion coefficient and specific volume of the substance, and changes in the mechanisms of deformation. The corresponding calculations of temperature distribution, thermodiffusion and distribution of the components of the melt have been carried out.

cond-mat.mtrl-sci↗

arXiv2023

Emission Transfer of Interstitial Atoms Under Shock Deformation of a Metal Surface

The process of anomalous transfer of interstitial atoms during impact deformation of the crystal surface is described theoretically. As shown that surface impact leads to the formation of a wave of inhomogeneous atomic displacements in the medium, which propagates from the surface into the depth of the crystal. The formation of a deformation wave leads to a change in the interatomic distance at the wave front and a change in the potential energy for interstitial atoms. Interstitial atoms at the front of the deformation wave receive an additional impulse, which leads to an increase in their kinetic energy and contributes their movement deep into the crystal.

cond-mat.mtrl-sci↗

arXiv2013

An energy gap in the spectrum of atomic excitations systems

It is shown that atoms in the system can be treated as quantum particles localized in potential wells, created by atomic potentials of neighboring atoms. As a result, the state of atoms in the liquid is characterized by wave functions and the discrete energy spectrum resulting in formation of s and p - zones corresponding to the ground and excited states of helium atoms, respectively, separated by a gap. The width of the gap in system equals ~8.5 K at T=0. Formation of the gap in the energy spectrum of atomic excitations in helium systems allows us to draw the analogy between the physical mechanisms of superfluidity and classical superconductivity.

cond-mat.other↗

arXiv2013

Specifics of thermodynamic description of nanocrystals

A method of statistical description of thermodynamic properties of nanocrystals is developed. It is established that size-dependent quantization of vibrational modes results in formation of excess pressure of the phonon gas acting outwards the crystal. Based on the concept of the phonon gas pressure, size dependence of thermodynamic properties of nanocrystals was described, and size influence on a shift of a phase transformation temperature was explained.

cond-mat.mes-hall↗

arXiv2009

Heat release in clusterization of nanoparticles

We show that the effect of size dependence of the melting temperature of nanocrystals may be used to govern anomalies of thermodynamic properties of nanocrystals in the premelting range. For example, if temperature of nanocrystals is near the melting point, their mechanical contact should result in a change of the temperature and release of some heat. We discuss fundamental possibility of construction of a "heat pump" to extract thermal energy from a low-temperature medium.

cond-mat.mtrl-sci↗

arXiv2008

Size effect on thermodynamic properties of free nanocrystals

We demonstrate that the discrete character of the vibrational spectrum of a small crystal accounts for size dependence of its thermodynamic properties and melting temperature. Using a self-consistent statistical method [Phys. Rev.B 66, 054302 (2002)] we derive the Gibbs free energy of free nanocrystalline plates and calculate the thermodynamic parameters as functions of plate thickness for Cu.

cond-mat.mtrl-sci↗