Temperature-Dependent Irradiation-Induced Clustering in a Fe-Mn-Ni Alloy

The formation of Mn-Ni-rich clusters has attracted huge scientific interests because it is responsible for irradiation-induced hardening of reactor pressure vessel steels. To gain deep insights into the formation of Mn-Ni clusters, the effects of irradiation temperatures on clustering in self-ion-irradiated Fe-Mn-Ni steel at room temperature, 250 degrees C and 350 degrees C are studied using atom probe tomography. This research uncovers that the Mn-Ni clusters evolve to different chemistries during irradiation at different temperatures. At room temperature and 250 degrees C, the Mn/Ni ratios of the clusters evolve toward 1:1, similar to the MnNi phase. At 350 degrees C, the Mn/Ni ratio of the Mn-Ni clusters evolves toward the Mn2Ni phase. Importantly, the clusters with different chemistries exhibit different hardening effects.

Automated summary

The study reveals that the formation of Mn-Ni clusters in Fe-Mn-Ni steel during irradiation at different temperatures leads to significant variations in their composition, with clusters exhibiting different hardening effects depending on their chemistry.