A structure–property correlation study of neutron irradiation induced damage in EU batch of ODS Eurofer97 steel

Within the framework of the European Fusion Development Agreement (EFDA), an EU batch of oxide-dispersion-strengthened (ODS) Eurofer97 steel samples have been irradiated with neutrons to nominal dose levels of 1 and 3 displacements per atom (dpa) in the High Flux Reactor (HFR) located in Petten to investigate irradiation induced changes in the microstructure and mechanical properties. The results of the irradiation-induced effects on the mechanical properties of this steel are published by Luzginova et al. (2011) [18]. In this paper, post-irradiation examination (PIE) by Transmission Electron Microscopy is performed on the material irradiated at 300 °C to investigate irradiation-induced microstructure dependence on the neutron irradiation dose and relate it to the observed mechanical properties. The results of this study revealed a presence of a high density of black dot damage and self-interstitial atom (SIA) dislocation loops in the microstructure after neutron irradiation to both 1 and 3 dpa dose levels. No dissolution of the ODS particles due to irradiation was observed. These results are discussed in relation with the irradiation hardening and shift in ductile to brittle transition temperature (DBTT) observed in this alloy at the above irradiation conditions.