Characterization of M2X formed during 5 MeV Fe2+ irradiation

The growth of M₂X phase in HT9 irradiated to high dpa was explored using self-ion irradiation. HT9 was pre-implanted with 10 appm He and irradiated with a raster-scanned Fe²⁺ beam with a damage rate of ∼1 × 10^-3 dpa/s at 460 °C. The precipitation of M₂X was observed and a combination of high resolution transmission electron microscopy (HRTEM), energy filtered transmission electron microscopy (EFTEM) and diffraction analysis was used to characterize the Cr-rich carbide observed at 250 dpa and above. Cr₂C was determined to be semi-coherent with the matrix such that _{[ 100 ] Cr2 C} / /[_100]α and _{[ 001 ] Cr2 C} / /_{[ 10 1 bar ] α} .with a = 2.71 Å and c = 2.82 Å.