Migrating and clustering of He atoms in Ti3SiC2: First-principles calculations

The diffusion path of single He atom in Ti3SiC2 was investigated by first principle calculations, showing that the He atoms generated homogenously in the material will quickly migrate into the Si layer at higher temperatures (>500 °C) although a small fraction of them may be trapped by vacancies in the C layer at room temperature. Our further calculations showed that the largest He clusters formed in the Si layer consists of no more than 7 He atoms, corresponding to volume swelling of only 2% at most, and the other He atoms may flow into the grain boundaries because the barrier for a He atom diffusing in the Si layer is only 0.05 eV. These results indicate that Ti3SiC2 owns good tolerance of He damage.