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[en] Helium release during isothermal and isochronal annealings from ceramic materials irradiated in the SM-2 reactor at the temperature of approximately 75 and 930 deg C up to 6x10₂₀, 7x10₂₀, 1.2x10₂₁ neutr./cm₂ (E >= 1MeV) is considered. It is shown that low-temperature (from 77 K) helium release is connected with a possibility of helium atom keeping on the surface of beryllium oxide particles. Gas release peaks are interpreted as release of helium being in the depth of material in the state of the highest mobility. Peaks on the curve of gas release are shifted towards lower temperature with the increase of radiation dose, increase of their half-width takes place. Evaluations of activation energy of helium migration and coefficients of seeming diffusion are obtained. A possibility of developing materials saturated with helium with decreased energy of crystal adhesion are obtained

[en] Properties of 160mm length cylindrical samples produced by impact shock of superconducting YBa₂Cu₃O_6.69 powder are investigated. Crtical temperature scatter by the cylinder length from 88 to 91K is ascertained. Superconducting transition broadening is connected with the occurrence of a large number of nonperfections in a crystal lattice after explosion. It is shown that as a result of explosion a ceramic core is produced with the density close to the theoretical one and a tight contact with steel or ceramic coating is realized

[en] A principal possibility of obtaining high non-equilibrium contents of helium in the state of substitution is predicted on the basis of analysis of theoretical and experimental data of different authors. Decrease of cohesive energy, temperatures and pressures of phase transformations is forecasted. A probability of a helium-vacancy (HeV) complex dissociation is higher than its migration. After HeV decomposition helium finds the outlet over interstitials quicker than vacancy, that is why material migration in non-equilibrium vacancies is possible under heating. It should result in essential increase of diffusion mobility of intrinsic and impurity atoms. Electrons with energy above 10 keV can destroy helium-vacancy complexes

[en] An attempt is made to create by means of neutron irradiation such defectiveness, the change in which during heating to T>=0.5 Tsub(melt) (Tsub(melt) - melting point) would result in the appearance in crystal of oversaturated solution of free vacancies - the main factor, increasing the rate of diffusion processes. It is shown, that at the optimum parameters of neutron irradiation of beryllium oxide the diffusion processes are accelerated by a factor of 10⁴-10⁷. The rates of powder sintering, microcracks healing, mass transfer on the surface increase. Experimental data, analysis of investigation results obtained by other authors shown, that dissociation of heliumvacancy complexes with liberation of vacancies, concentration of which grows higher the equilibrium one, is the most probable reason for diffusion acceleration

[en] Behaviour of helium voids and cracks in gold films of thickness about 600 A prepared by magnetron sputtering have been studied by transmission electron microscopy. The gold films were heated directly in the transmission electron microsocope. It was found that self-diffusion coefficient in gold films containing helium increases up to 10⁸-10¹¹ order of the magnitude in comparison with chemically pure gold films. While annealing from the temperatures of 423 K the appearance and disappearance of voids and crack healing were observed. The observed phenomena are explained by supersaturation of gold films of vacancies, being formed as a result of helium-vacancy complexes decay. A conclusion is made on the considerable influence on the acceleration of diffusion processes in gold films with large content of helium

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