Stability and migration of transmutation atoms (H/He) in Ti3AlC2: first principles calculations

Abstract

The stability and migration behaviors of impurity H and He atoms have been investigated by using first principles calculations in Ti₃AlC₂. The formation energies of interstitial and HV/HeV clusters have been calculated to assess the energetically favorable sites. The interstitial sites near the Al atomic layer (open space) are preferentially occupied by the impurity H and He atoms. HV_Al cluster is easily formed in the open space. It is observed that a single H atom prefers jumping to a metastable interstitial site and then to a stable position along the path of 1 → c → 5 in z direction. The migration of impurity H shows a remarkable anisotropy in Ti₃AlC₂.