Stability and interatomic potentials for M-doped TiV alloys (M=H, He, C, O) by first-principles simulations

TiV alloy is an important candidate structural material of hydrogen storage and fusion reactor systems. It will be inevitably invaded by impurity atoms such as H, He, C, and O in service. The first-principles simulations were performed to study stability and interatomic potentials for M-doped TiV alloys (M=H, He, C, O). The results showed that He has a positive binding energy, while H, C, and O have negative ones, which means that H, C, and O are doped into TiV alloys more easily than He. For H, He, C, and O atoms, on the other hand, the tetrahedral sites have lower binding energy and smaller lattice distortion than the octahedral interstitial sites, so they can be embedded in the tetrahedral sites more stably. The modified embedded atom method potential was used for characterizing V–Ti interaction and Lennard-Jones potential for V–M and Ti–M interactions. All the potential parameters were determined according to the first-principles simulations