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 × 10¹⁶ ions/cm² 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_0.9 and ZrC_0.8. With the increase in carbon vacancy concentration, the size of the dislocation loops gradually decreased. Few dislocation loops were found in ZrC_0.7 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.