Control of changes in the defect structure of titanium saturated with hydrogen

Abstract

The hydrogenated samples of technical titanium were investigated using the EPA method and the measurements of the thermal electromotive force for these samples saturated with a different amount of hydrogen. The structure of the hydrogenated samples was studied by the X-ray diffraction method. The results have shown that the hydrogenated titanium structure starts changing at the same time, depending on the amount of added hydrogen. The intensity of the annihilation process increases with the increase in the hydrogen concentration in a-titanium up to the values of 4% wt and does not change up to the values of 5% wt ([alpha]+[beta]) - titanium. At the same time, the value of the thermal electromotive force decreases in this range of values. The annihilation intensity is stabilized for the values of 5% wt, and the value of the thermal electromotive force is increased. The inflection point for the thermal electromotive force versus the hydrogen concentration corresponds to the formation of [delta] - hydrides. The increase in the positron lifetime starts in the concentration range of 6-8% and moves to the stable level up to the concentrations of 21-22%. In this range, there is a transition from the wt ([alpha]+[beta]) to the wt ([alpha]+[delta) phase. The lifetime of positrons and the number of defects are increased, the value of the thermal electromotive force is reduced (up to the concentration of 24%), then there is a stabilization mode for all these parameters up to the values 32% wt.