High temperature effects on irradiation damage of Ti2AlC

As one of the MAX phases, Ti2AlC combines attractive properties of both ceramics and metals, and has been suggested for potential nuclear reactor applications due to its excellent resistance to irradiation. This work is aimed at investigating the high temperature effects on evolution of irradiation damage in the MAX phase Ti2AlC. Ti2AlC was irradiated with 1.1 MeV C4+ ions at 298 K and 873 K with fluences ranging from 2 × 1015 cm−2 to 6 × 1016 cm−2. Scanning electron microscopy (SEM), Raman spectra, grazing incidence X-ray diffraction (GIXRD), transmission electron microscopy (TEM), and nanoindentation were used to characterize the evolution of microstructures and mechanical properties at both temperatures. Significant crackings along grain boundaries were observed in 298 K, which were not observed in the samples irradiated at 837 K. No amorphization was found in the GIXRD analyses and TEM characterization, and some fcc phases were formed during high dose irradiation at 298 K. Raman spectra show that all the vibration modes of Ti2AlC decreased severely in room temperature irradiation, but they nearly remained unchanged in high temperature irradiation at the dose of 2 × 1015 cm−2. Nanoindentation shows significant hardening for Ti2AlC irradiated at high temperature, suggesting the presence of irradiation-induced defects. The current study reveals that the irradiation tolerance of Ti2AlC is significantly improved with increasing temperature, demonstrating the great potential of Ti2AlC for using in advanced nuclear reactors.