Nuclear Fusion | 2019
The influence of Fe-ion irradiation on the microstructure of reduced activation ferritic-martensitic steel Eurofer 97
Abstract
Reduced activation ferritic/martensitic steels for in-vessel components of a fusion reactor have shown a decrease in plasticity and radiation hardening at low irradiation temperatures. The formation of dislocation loops and embryos of α phase is considered the main reason for these effects. In this work, Eurofer 97 steel was irradiated with 5.6 MeV Fe2+ ions up to 1020 m−2 at 250, 300 and 400 °C. Transmission electron microscopy study of ion irradiated samples revealed nucleation of dislocation loops. The pair-correlation analysis of atom probe tomography data detected an initial stage of solid solution decomposition. The hardening of ion-irradiated Eurofer 97 was calculated with the dispersed barrier hardening model, taking into account radiation-induced dislocation loops to compare it with the change of yield stress in neutron-irradiated Eurofer 97. According to the obtained results, it can be supposed that the formation of dislocation loops plays the main role in the low-temperature radiation hardening of Eurofer 97 at a dose level up to ~10 dpa.