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 Fe2+ ions to emulate nanocluster morphologies resulting from neutron irradiation to 3 dpa at 500 degrees C. Using this prescribed shift, Fe2+ ion irradiation was conducted on three F/M alloys (T91, HCM12A, and HT9) to 3 dpa at 370 degrees C. Atom probe tomography characterization shows that the morphologies for Si-Mn-Ni-rich and Cu-rich nanoclusters following Fe2+ irradiation at 370 degrees C are comparable to the nanocluster morphologies after neutron irradiation at 500 degrees 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.

Automated summary

This study investigates the irradiation evolution of Si-Mn-Ni-rich nanoclusters in F/M alloys using two simulation models. The results show that the morphology of the nanoclusters after Fe2+ ion irradiation is comparable to that after neutron irradiation at a higher temperature.