Roles of silicon-layer in Ti₃SiC₂ materials response to helium irradiation: new insights from first-principles calculation

Using the first-principles method based on density functional theory, the effect of helium irradiation on Ti₃SiC₂ has been investigated. It was observed that helium atoms prefer to accumulate within the layers where Si atoms have been dislodged creating 2-dimensional channels and bubbles which strongly promotes cleavage fractures between adjacent Ti-Si layers. At high temperature the He atoms diffuse out of these bubbles enabling the diffusion of the mobile Si back to their original sites and the annealing of the material back to the original structure. This behavior may play a positive role in the resistance of Ti₃SiC₂ to helium irradiation making it a potential candidate for future nuclear reactor applications in the future