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Hydrogen saturated samples of technically pure titanium have been studied by the electron-positron annihilation method (EPA), coupled with the thermoelectric power measurements performed in these samples saturated by different amount of hydrogen. The structure of the hydrogenated samples was additionally investigated by X-ray diffraction. The complete coincidence of the moment of occurrence of a change in the structure of hydrogenated titanium depending on the amount of introduced hydrogen has been established. The intensity of positron annihilation drops with increasing hydrogen concentration in α-titanium to 0.04 wt % and then remains unchanged up to values of 0.05 wt % ($$\alpha + \delta $$) -titanium to increases afterwards. At the same time, a sharp change in the values of the thermoelectric power occurs in this range. In the region of 0.05%, the annihilation rate stabilizes and begins to increase, while the thermoelectric power begins to decrease slowly. The inflection point on the dependence of thermoelectric power on hydrogen concentration corresponds to the onset of the formation of titanium $$\delta $$-hydrides. An increase in the positron lifetime is observed in the concentration range of 0.05–0.08 wt %, then the lifetime stays stable up to concentrations of 0.08–0.12 wt %. A transition from ($$\alpha + \beta $$) to ($$\alpha + \delta $$) phase is formed in this range. Next, the positron lifetime increases, as does the number of defects, while the thermoelectric power gradually drops (to a concentration of 0.24 wt %). This is followed by a stabilization mode of all the above parameters to 0.35 wt %.

The possibility of obtaining hydrogen storage materials based on TiCr2 intermetallic compounds by the methods of melting in abnormal glow discharge plasma and electron beam melting is shown. The use of melting in abnormal glow discharge plasma leads to the formation of a Laves phase of the C36 structural type, while electron beam melting allows the C14-type Laves phase to be obtained. It is established that the formation of Laves phases of different structural types is associated with different cooling rates, which is caused by the specific features of the methods for synthesizing intermetallic compounds.

We have obtained restructured zinc (high-purity zinc prepared by mechanothermal action of various intensity levels) and have analyzed its structure by the positron spectroscopy methods. Bulk vacancytype defects (vacancies and vacancy clusters), as well as the regions with an extended crystal lattice, have been discovered in the restructured samples and analyzed quantitatively. These effects are responsible for the emergence of internal microstresses in the material, which modify its properties.

The VT1-0 titanium alloy (phase α-Ti) with various hydrogen and hydrogen-vacancy concentrations has been studied. The stability of the 32-atom Ti–nV–mH supercell (n is the number of the V vacancies, and m is the number of hydrogen atoms H) with varying numbers of vacancies and hydrogen atoms has been calculated from the first principles. The structural state of the α-Ti phase has been identified by the Rietveld method based on the calculations of the supercell stability and the data on the defect concentration obtained using positron spectroscopy. The complete structural information on the considered states of the α-Ti phase (the lattice parameters, spatial distribution of titanium and hydrogen atoms and vacancies) has been obtained.

Using the method of measuring the positron lifetime spectra and Doppler broadening annihilation line spectroscopy, the annealing of defects in submicrocrystalline nickel produced by equal channel angular pressing has been studied. In as-prepared samples, the positrons are trapped by dislocation defects and vacancy complexes inside crystallites. The size of vacancy complexes decreases with increasing annealing temperature in the interval ΔT = 20–300°C. However, at T = 360°C, the complexes start growing again. The dependence of S-parameter on W-parameter derived from the Doppler broadening spectroscopy has two parts with different inclinations to axes that correspond to different types of primary centers of positron trapping in submicrocrystalline nickel. It has been elucidated that, at recovery stage in the temperature interval ΔT = 20–180°C, the main centers of positron trapping are low-angle boundaries enriched by impurities, while at in situ recrystallization stage in the temperature interval ΔT = 180–360°C, the primary centers of positron trapping are low-angle boundaries.