The positron annihilation characteristics of deformed and annealed material were investigated. The temperature dependence of the line-shape parameter for deformed samples was described by a model that was based upon a competition between positron trapping in dislocations and vacancy-like defects. The results indicated that positron trapping in deformed samples was controlled by dislocations. Positron de-trapping from dislocations did not appear to be responsible for the positive temperature dependence of the line-shape parameter. Analysis of the experimental data yielded a positron-dislocation binding energy of 0.018eV. Recovery of the deformation damage occurred at temperatures of between 373 and 703K. A value of 199ps was deduced for the positron lifetime in the bulk.

T.Leguey, M.A.Monge, R.Pareja, J.M.Riveiro: Journal of Physics - Condensed Matter, 1995, 7[30], 6179-85