Role of Nanolaminated Crystal Structure on the Radiation Damage Tolerance of Ti3SiC2: Theoretical Investigation of Native Point Defects

Abstract EN

Nanolaminated Ti3SiC2, a representative MAX phase, shows excellent tolerance to radiation damage.

In this paper, first-principles calculations were used to investigate the mechanism of intrinsic point defects in order to explain this outstanding property.

Formation energies of intrinsic point defects are calculated and compared; and the results establish a low-energy disorder mechanism in Ti3SiC2.

In addition, the migration energy barriers of Si vacancy, Si interstitial, and TiSi antisite yield very low values: 0.9, 0.6, and 0.3 eV, respectively.

The intercalation of Si atomic plane between Ti3C2 nanotwinning structures dominates the formation and migration of intrinsic native point defects in Ti3SiC2.

The present study also highlights a novel method to improve radiation damage tolerance by developing nanoscale-layered structure which can serve as a sink or rapid recovery channel for point defects.