V. A. Fedorov

Behavior of alkali halide crystals under the influence of a low-energy flux of β particles

The effect of a low-energy flux of electrons on alkali halide crystals is investigated. The pulse luminescence of crystals in the visible and ultrashort wavelength ranges is found. The dependence of luminescence on the potential of the crystal and color centers is revealed.

On crack nucleation in zinc upon interaction of basal and pyramidal dislocations

AbstractThe interaction of intersecting basal and pyramidal dislocation pileups in single-crystal zinc has been analyzed. Different versions of the formation of sessile (1/3[4

Structure and Properties of SiO x Films Prepared by Chemical Etching of Amorphous Alloy Ribbons

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Healing of cracks in alkali halide crystals

3]) and cleavage ([0001]) dislocations (microcrack nuclei) are considered. The merging of the head dislocations in pyramidal pileups is shown to be preferred. The conditions for thermally activated dislocation merging are derived. The conditions for crack opening according to the Gilman-Rozhanskiĭ mechanism are discussed. It is analytically established that the breaking stress, normal to the (0001) plane in the region of microcrack nucleation, exceeds the theoretical strength.

On microcrack nucleation at twin vertices and boundaries in bcc and fcc metals

The effect of UV irradiation on the dislocation motion in ionic crystals and relaxation growth of elastic twin in Iceland spar has been investigated. It is shown that UV radiation causes stress relaxation in crack tips, which is related to a change in the dislocation structure. It is suggested that the observed effects are based on the interaction of dislocations with low-energy excitons.

Effect of dislocation distribution in twin boundaries on the nucleation of microcracks at the twin tip

The structure and the physical properties of amorphous SiOx films prepared by chemical etching of an iron-based amorphous ribbon alloy have been studied. The neutron diffraction and also the atomicforce and electron microscopy show that the prepared visually transparent films have amorphous structure, exhibit dielectric properties, and their morphology is similar to that of opals. The samples have been studied by differential scanning calorimetry, Raman and IR spectroscopy before and after their heat treatment. It is found that annealing of the films in air at a temperature of 1273 K leads to a change in their chemical compositions: an amorphous SiO2 compound with inclusions of SiO2 nanocrystals (crystobalite) forms.

Healing of cracks arrested at asymmetric cleavage in alkali-halide crystals and calcite

It is shown that the synergetic effect heating and an electrical field have on ionic crystals leads to the emission of matrix ions from the free surface of a crystal. Some fundamental patterns of emission are established, and the work function of ions of different signs is experimentally determined. The creation of emission current between the surfaces of a crack results in microplastic shears on the bombarded surface, reducing the work function of ions. The work function of ions is in this case also estimated.

Analytical estimation of dislocation distribution at the tip of arrested cracks

The healing of micro-and macrocracks under local heating and x-ray irradiation of LiF single crystals is studied. The main features revealed in crack healing due to local actions are described. The contribution of the plastic zone formed upon the arrest and healing of a crack to the strength of the crystal is estimated.