Annealing of the defects which were introduced by electron irradiation to a dose of 6 x 1021/m2 at temperatures below 293K was investigated in single-crystals, using positron annihilation spectroscopy. The recovery of the positron annihilation parameters in V monocrystals indicated that, under the present irradiation conditions, defect annealing in V took place at temperatures ranging from 310 to 470K; without the formation of micro-voids. In the case of the alloys, the onset of recovery shifted to 460K. The width of the annealing stage gradually broadened with increasing Ti content, and micro-voids could form at the end of the recovery stage. It was concluded that the results indicated that vacancy release from vacancy-interstitial impurity pairs, and their subsequent recombination with interstitial loops, was the recovery mechanism in pure V. In the case of V-Ti alloys, it was proposed that vacancy-Ti-interstitial impurity complexes and vacancy-Ti pairs were the defects that were responsible for positron trapping. The broadening of the recovery stage with increasing Ti content was suggested to indicate that Ti, as solute, was a very effective trap for vacancies in V.

T.Leguey, R.Pareja, E.R.Hodgson: Journal of Nuclear Materials, 1996, 231[3], 191-8