The effects of He clusters on the mechanical properties of Ti3AC2 (A = Ge, Si): first-principles studies

Abstract

Herein, the damage to the mechanical properties of Ti₃AC₂ (A = Ge, Si) was systematically investigated by first-principles calculations. It is known that the interstitial He atoms homogenously generated in the materials would finally migrate to the A layer and form clusters of no more than 7 He atoms at a mono-vacancy in the A layer, and the cluster of 7 He atoms reduces the ideal tensile strength of Ti₃SiC₂ (or Ti₃GeC₂) to about 37.3% (or 35.5%). The strain simulations showed that the fracture would mostly occur around the A layer and enhances with increase in the cluster size, while the Ti₃C₂ blocks are relatively stable during tension. Although the He damage to the mechanical properties shows the similar trend for Ti₃SiC₂ and Ti₃GeC₂, the former displays better properties for applications in nuclear structural devices.