Microstructure Evolution in ZrC with Different Stoichiometries Irradiated by Four MeV Au Ions.

ZrC ceramics with different stoichiometries were irradiated under a four MeV Au ion beam in doses of 2 × 10 ions/cm at room temperature, corresponding to ~130 dpa. Grazing incidence, X-ray diffraction and transmission electron microscopy were performed to study the radiation damage and microstructure evolution in ZrC ceramics. With the decrease in C/Zr ratio, the expansion of ZrC lattice became smaller after irradiation. Some long dislocation lines formed at the near-surface, while, in the area with the greatest damage (depth of ~400 nm), large amounts of dislocation loops formed in ZrC, ZrC and ZrC. With the increase in carbon vacancy concentration, the size of the dislocation loops gradually decreased. Few dislocation loops were found in ZrC after irradiation, and only black-dot defects were found in the area with the greatest damage. For the non-stoichiometric ZrC, with the increase of the intrinsic vacancies, the number of C interstitials caused by irradiation decreased, and the recombination barrier of C Frenkel pairs reduced. The above factors will reduce the total number of C interstitials after cascade cooling, suppressing the formation and growth of dislocation loops, which is significant for the enhancement of the tolerance of radiation damage.