LAUSR

Abstract Understanding irradiation-induced clustering of alloying elements in ferritic steels is of significance in gaining essential knowledge for guiding design and development of advanced ferritic steels with a high resistance to irradiation damage. This research conducted Fe-ion-irradiation experiments on a Fe-1.35Mn-0.20Si steel at room temperature, 250°C and 350°C, respectively, under irradiation doses up to 1.5 dpa. Careful atom probe tomography investigations reveal that Mn and Si atoms exhibit unique irradiation-induced clustering behavior. In particular, the rises in irradiation temperature and dose mainly promote the nucleation rather than the growth of the Mn-Si clusters. This is in great contrast with the simultaneous significant nucleation and growth of Ni-Si clusters in Fe-Ni-Si alloy under the same irradiation condition. This observation indicates that cluster evolution behavior is highly sensitive to the alloy chemistry. The weak interaction between Mn and Si is likely responsible for the unique clustering behavior of Mn and Si in the steel under such irradiation.