Positron annihilation in titanium alloys modified by proton irradiation

Measurements of angular distribution annihilation photons (ADAP) were applied to investigate the behavior of point defects in the annealed, plastically deformed and the irradiated titanium alloys. It is shown that irradiation by protons with E = 30 MeV is accompanied by formation of vacancy clusters in titanium alloys. The presence of the deformation defects and alloying elements in the initial structure of the material leads to considerable changes in radiation damage spectra. It is determined that the role of the initial defects in the radiation damage of titanium alloys caused by a proton irradiation becomes apparent not only in the deceleration of the swelling process, but also in the evolution, transformation and the redistribution of the initial defects. These findings confirm once again a necessity of taking into account the presence of impurity atoms and preliminarily created structural damages in an irradiated material.