Migration behavior of vacancies in electron irradiated Fe‐Cu alloys

Abstract

The formation of Cu precipitates in Cu containing steels is one of the key factors leading to embrittlement in reactor pressure vessel steels. Cu precipitates are formed by the migration of vacancies in steels and the behaviour of these vacancies is therefore important. In the present study, vacancies were introduced into Fe‐Cu alloys by electron irradiation with 28 MeV at 100 K. 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‐0.3 mass% Cu to Fe‐0.6 mass% Cu on the migration of vacancies and the formation of Cu precipitates was negligible small. The formation of Cu precipitates was found to decrease the migration temperature of vacancies. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Characterization of proton irradiation-induced defect in the A508-3 steel by slow positron beam

“…Vehanen et al [15] found that in pure iron mono-vacancies are mobile at stage III around 220 K causing vacancy clustering into small three-dimensional agglomerates. The study of Cao et al [16] also indicated that electron irradiation-induced mono-vacancies started to migrate at 220 K for annealed Fe-0.3Cu alloys and at 280 K for quenched Fe-0.3Cu alloys. Juan and Hoffmann found that the vacancies act as a strong trap for H. The Fe atoms, initially more strongly bonded to each other as a result of vacancy introduction (by depopulation of Fe-Fe antibonding orbitals), diminish their Fe-Fe bonds as the new Fe-H bond is formed.…”

Effects of copper precipitates on microdefects in deformed Fe-1.5 wt%Cu alloy

“…The steels are applied in the automotive industry and Cu-bearing steels have excellent ductility and high strength by control of Cu precipitates during aging or cooling [1][2][3][4][5][6][7][8]. Cu precipitates also play an important role in the irradiationinduced embrittlement in ferriticalloy [9][10][11][12]. It is well known that Cu atoms and microdefects migrate and aggregate reciprocally during deformation, irradiation, or aging [13,14].…”