Moessbauer and positron annihilation study of tin-vacancy interaction during the recovery of a dilute Al-Sn alloy

Tin-vacancy interaction was studied in a dilute Al(Sn) alloy, quenched from 6130C to -700C and isochronally heat treated up to 2500C, using parallel positron lifetime and Moessbauer spectroscopy. For the interpretation of the results, a simple model was developed including tin-monovacancy tin-divacancy and tin-tetravacancy complexes as well as more complicated tin-vacancy agglomerates as important participants of the recovery process. According to this model, the changes observed in the positron lifetime and Moessbauer spectra can be explained by the gradual transformation of these complexes to simpler ones through transitional configurations. Only two lines could be observed in the Moessbauer spectra and the results suggest that a single vacancy has minor effect on the isomer shift of the line corresponding to tin in substitutional lattice site. (orig.)