Self-ion irradiation of ZrC up to 300 displacements per atom

Abstract

ZrC is a candidate fuel matrix for high-temperature gas-cooled reactors and a potential first wall materials for fusion reactors, owing to its high melting point, low neutron capture cross-section, and good mechanical properties. The radiation tolerance of ZrC is critical in such applications. Due to the excessive intrinsic vacancy concentration that naturally occurs in ZrC, it is expected that ZrC has excellent defect recombination efficiencies. In this study, ZrC is manufactured using plasma sintering techniques. Self-ion irradiation by 5 MeV carbon ions is carried out at room temperature, 300 °C, and 600 °C, with ion fluences up to 300 displacements per atom (dpa). Transmission electron microscopy characterization shows that ZrC does not exhibit amorphization under any of these irradiation conditions. No phase changes are observed. Raman spectra display well-separated acoustic and optical bands in the wavenumber region below 800 cm⁻¹. These bands show gradual broadening with increasing damage levels. For wavenumbers higher than 800 cm⁻¹, D and G modes, absent in the virgin sample, appear after irradiation. The increasing D/G mode intensity with rising damage levels suggests localized graphitization. Overall, the study demonstrates the excellent amorphization tolerance of ZrC under extreme conditions.