Microstructure evolution in Si+ ion irradiated and annealed Ti3SiC2 MAX phase

Abstract Ti 3 SiC 2 samples were irradiated by a 6‐MeV Si + ion to a fluence of 2 10 16 Si + ions/cm 2 at 300°C followed by annealing at 900°C for 5 h. A transmission electron microscope was used to characterize microstructural evolution. The phase of Ti 3 SiC 2 transformed from the hexagonal close‐packed (HCP) to a face‐centered cubic structure after irradiation. Hexagonal screw dislocation networks were identified at the deepest position of the irradiated area, which are the products of dislocations reactions. After annealing, the irradiated region has reverted to the original HCP structure. High‐density cavities and stacking faults were formed along the basal planes. In addition, ripplocations have been observed in the irradiated region in the Ti 3 SiC 2 sample after annealing. Our insights into the formation processes and corresponding mechanisms of these defect structures might be helpful in the material design of advanced irradiation tolerance materials.