Evolution of irradiation defects in Ti2AlC ceramics during heavy ion irradiation.

The evolution of irradiation defects in Ti 2 AlC under Kr ion irradiation at room and elevated temperatures has been investigated. The dependence of defect size and density on the irradiation dose and temperature was characterized by in-situ transmission electron microscopy (TEM) irradiation experiments. At 25–800 °C, interstitial-type dislocation loops with several nanometers in diameter form on the basal plane of Ti 2 AlC mostly with a Burgers vector of 1/2[0 0 0 1], and no voids have been observed. The number density of dislocation loops approaches saturation at a level of about 2 dpa at 800 °C. Ti 2 AlC samples remain crystalline in structure without amorphization or phase transformation. However, the localized disorder of atomic positions on the basal plane of the irradiated Ti 2 AlC was revealed by high-resolution transmission electron microscopy (HRTEM) studies, which increases with irradiation dose while decreases with elevated temperatures. [ABSTRACT FROM AUTHOR]