Temperature Shift for Nanocluster Evolution in Ion-Irradiated Ferritic-Martensitic Alloys

Ferritic-martensitic (F/M) alloys are leading candidate materials for advanced reactors, but are known to experience nucleation and growth of solute nanoclusters, causing irradiation-induced embrittlement. In this study, two simulation models are applied to describe Si-Mn-Ni-rich nanocluster irradiation evolution, with each model predicting a negative temperature shift for Fe 2+ ions to emulate nanocluster morphologies resulting from neutron irradiation to 3 dpa at 500°C. Using this prescribed shift, Fe 2+ ion irradiation was conducted on three F/M alloys (T91, HCM12A, and HT9) to 3 dpa at 370°C. Atom probe tomography characterization shows that the morphologies for Si-Mn-Ni-rich and Cu-rich nanoclusters following Fe 2+ irradiation at 370°C are comparable to the nanocluster morphologies after neutron irradiation at 500°C in all three F/M alloys, confirming the predicted shift. More precise temperature shifts for solute nanocluster irradiation evolution are likely dependent on the clustering species in question and their respective diffusion rates.