Radiation-induced segregation/precipitation in Fe-Ni and Fe-Mn model alloys: Dose rate and solute effects

International audienceThe evolution of radiation damage in steels is a major issue for the safe operation of Nuclear Power Plants. Mn and Ni contribution to the formation and evolution of microstructural features remains a controversial issue. The present study aims at investigating their effects on microstructure by irradiating undersaturated BCC Fe-3.3at.%Ni and Fe-2.8at.%Mn model alloys. Two different ion irradiation conditions have been applied to study the effect of irradiation dose rate in both of these Fe-based alloys at a temperature of 673 K. In all cases, irradiation promotes the formation of dislocation loops. In the FeNi alloy, radiation-induced segregation is observed on loops, leading to precipitation of a FCC phase in the low dose rate irradiation condition only. In the case of FeMn, even if no precipitation occurred, highly enriched decorated dislocation loops are observed, leading to a higher Mn segregation at radiation defects than Ni