IVEM3_ANA2_400C_5dpa_3333HeperDPA.mp4

This video shows real-time in-situ TEM imaging of an additively manufactured Fe-9Cr alloy subjected to simultaneous 1 MeV Kr²⁺ and 12 keV He⁺ ion irradiation at 400°C, with a helium co-injection rate of 3,333 appm He/dpa. The video captures the microstructural evolution from 0 to 5 dpa within a representative region of interest. A pronounced increase in dislocation loop density is observed, with the near-exclusive formation of small (~1 nm) a⟨100⟩ loops and a marked suppression of larger a/2⟨111⟩ loops. These features illustrate the dramatic impact of high helium irradiation levels on dislocation loop populations, as discussed in the main manuscript.