The formation of Cu precipitates in Cu containing steels was one of the key factors leading to embrittlement in reactor pressure vessel steels. Cu precipitates were formed by the migration of vacancies in steels and the behaviour of these vacancies was therefore important. In the present study, vacancies were introduced into Fe-Cu alloys by electron irradiation with 28 MeV at 100K. The effects of Cu concentration and tiny Cu precipitates on the migration of vacancies and growth of precipitates in Fe-Cu alloys were investigated by positron annihilation lifetime measurements. The effect of Cu concentration between Fe-0.3wt%Cu to Fe-0.6wt%Cu on the migration of vacancies and the formation of Cu precipitates was negligibly small. The formation of Cu precipitates was found to decrease the migration temperature of vacancies.

Migration Behavior of Vacancies in Electron Irradiated Fe-Cu Alloys. X.Cao, Q.Xu, K.Sato, T.Yoshiie: Physica Status Solidi C, 2009, 6[11], 2355–8