POSITRON-ANNIHILATION LIFETIME STUDY OF IRRADIATED AND DEFORMED FE AND NI

In order to investigate the fundamental behaviors of radiation-induced defects, especially vacancy type defects and also deformation-induced dislocations and vacancies, positron annihilation lifetime measuremen ts have been performed Tor Fe, Fe-Cu and Fe-Si irradiated with electro ns at low temperature (77 K) and also for Ni deformed at room temperat ure, From the isochronal annealing experiments it was found that vacan cies become mobile above 200 K and form microvoids in Fe, but in Fe-Cu and Pe-Si alloys the interaction between vacancies and solute atoms s ignificantly suppresses the microvoid formation process. In Fr-Cu allo y, instead of microvoid formation it was considered that vacancy-Cu co mplexes are formed by judging the value of positron lifetime, In the d eformed Ni positron lifetime decreased gradually as the isochronal ann ealing temperature increased, From this result and positron lifetime c alculation it was suggested that in deformed Ni positrons are trapped and annihilated at complexes of a dislocation and deformation-induced vacancies.