Characterization of M2X formed during 5Â 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]Cr2C//[100]α and [001]Cr2C//[101¯]α.with a = 2.71 Å and c = 2.82 Å.