Positron Spectroscopy of Hydrogen-Loaded Ti-6Al-4V Alloy with Different Defect Structure.

The defect structure of annealed cast, electron beam melted and ultrafine-grained titanium Ti-6Al-4V alloys before and after hydrogenation was studied. It has been established that before hydrogenation the predominant types of defects in electron beam melted and ultrafine-grained titanium alloy are dislocations and low-angle boundaries, respectively. The cast alloy after annealing is defect-free material. Hydrogenation from the gas phase to 1:00 ± 0:15 wt% leads to an increase of the concentration of the predominant type of defects. Moreover, vacancy complexes also presented in electron beam melted and ultrafine-grained Ti-6Al-4V alloys interact with hydrogen and form hydrogen-vacancy complexes. [ABSTRACT FROM AUTHOR]