Microstructural evolution of zirconium diboride irradiated with 5–10 MeV Au ions at room temperature and 570 °C

Abstract

Zirconium diboride was irradiated with 5 MeV Au^2 + , 7 MeV Au⁴⁺ and 10 MeV Au³⁺ ions at room temperature and 570 °C to doses from 1 to 8 displacements per atom (dpa). Grazing incidence X-ray diffraction (GIXRD) analysis revealed no secondary phase formation. Rietveld analysis of the GIXRD data indicated an accumulation of microstrain at low dpa and room temperature. Dislocations observed in transmission electron microscopy (TEM) cross-sections are likely the main contributor to the microstrain. High dpa and high-temperature samples exhibit lower lattice distortion than lower dpa samples, suggesting the presence of enhanced defect recovery at elevated temperatures and dislocation annihilation at higher doses. Positron annihilation lifetime spectroscopy (PALS) analysis showed no conclusive evidence of void growth at either temperature. These findings provide insights into the microstructural response of ZrB₂ to heavy ion irradiation, suggesting stability up to 8 dpa in typical reactor operating conditions.