Irradiation resistance of MAX phases Ti3SiC2 and Ti3AlC2: Characterization and comparison

The microstructural evolution and the changes in mechanical properties of 7 MeV Xe26+-ion-irradiated Ti3SiC2 and Ti3AlC2 were investigated. At room temperature (RT), compared with Ti3SiC2, Ti3AlC2 showed a better resistance to irradiation damage, but underwent a more severe phase transition from α phase to β phase. Rietveld refinement of X-ray diffraction patterns showed that the fraction of β phase of Ti3SiC2 and Ti3AlC2 samples irradiated at RT to a dose of 2 × 1015 ions/cm2 are 28.05% and 57.42%, respectively. At a dose of 4 × 1015 ions/cm2, the crystal lattice of Ti3AlC2 was hardly damaged, while the lattice of Ti3SiC2 was heavily distorted. The hardness of Ti3SiC2 and Ti3AlC2 increased after RT irradiation, due to defect pinning effect. Moreover, both MAX phases irradiated at 600 °C showed much better stabilities than after irradiation at RT.