Modeling Radiation-Induced Segregation in Ferritic-Martensitic Steels

As ferritic-martensitic (FM) steels receive increasing interest, due to the development of Generation IV fission reactors and fusion reactors, it is imperative to understand how the metals will behave under irradiation. Of the radiation effects, radiation-induced segregation (RIS) is of particular concern as it can lead to the formation of intermetallic phases, stress corrosion cracking, and other detrimental effects. However, predicting RIS in FM steels is more complex due to the lack of consistent trends in experimental results. Therefore, we developed a program to simulate RIS in FM alloys. By performing a sensitivity analysis of the input parameters, we found the model to be most sensitive to the defect migration energies. Although the general Chromium (Cr) concentration profile appeared to follow that of experiments, the dose dependence and bulk Cr concentration dependence were not accurately reproduced, and it became obvious that the IK model may be too simple and too sensitive to the input parameters to accurately predict all of the effects of the segregation of Cr.