Defect Structures during Incubation Period of Void Swelling in Austenitic and Ferritic Alloys Studied by Positron Annihilation Spectroscopy

Abstract

ABSTRACTIn order to understand the vacancy behavior during incubation period before steady state void swelling, positron annihilation lifetime measurements was performed after isochronal annealing of austenitic stainless steel (Ti added modified SUS316SS) and ferritic stainless steel (F82H) irradiated by neutrons and electrons to a dose of 0.2 dpa. By electron and neutron irradiations below 363 K, vacancies and nano-voids containing of few vacancies were formed in both alloys. By increasing annealing temperatures, the lifetime decreased without forming nano-voids. The change of lifetime during the annealing indicated the formation and growth of staking fault tetrahedra (Ti added modified SUS316SS) and the annihilation of vacancies at precipitates (F82H).