Characterisation of Irradiation Damage in Fe-3Cr and Fe-5Cr: A Study on the Effects of Chromium Content and Temperature
Fe–Cr binary alloys serve as simplified model systems to study irradiation damage relevant to fusion structural materials. Here, Fe-3%Cr and Fe-5%Cr samples were irradiated with 4 MeV Fe ions with a dose rate of 4 × 10⁻⁵ dpa/s across a linear thermal gradient (120°C–480°C) in a single experiment, enabling direct comparison of temperature and Cr content effects under identical conditions. Depth-resolved Laue micro-diffraction (~10⁻⁴ strain sensitivity), nanoindentation, and AFM reveal non-monotonic evolution of lattice strain and hardness: both decrease with temperature up to ~300°C, then increase beyond. This turning point reflects a shift from enhanced defect mobility and partial recovery to solute-defect clustering and cavity formation, which stabilize damage. Fe-3%Cr shows consistently higher strain and hardening than Fe-5%Cr, especially at lower temperatures. Minimal change in post-indentation pile-up indicates limited softening or localization. These results highlight how Cr content and temperature jointly affect irradiation response, offering new insights into defect evolution in fusion-relevant alloys.