Based on experiments and first-principles calculations, a Ni–Al–Re system embedded atom method (EAM) potential is constructed for the γ(Ni)/γ′(Ni3Al) superalloy. The contribution of the inner elastic constants is considered in the fitting of Re with a hexagonal close-packed structure. Using this potential, point defects, planar defects and lattice misfit of γ(Ni) and γ′(Ni3Al) are investigated. The interaction between Re and the misfit dislocation of the γ(Ni)/γ′(Ni3Al) system is also calculated. We conclude that the embedding energy has an important effect on the properties of the alloys, such as the planar fault energies of Ni3Al, by considering the relationship between the charge transfer calculated from first-principles, the elastic constants of Ni3Al and the host electron density of the EAM potential. The multi-element potential predicts that Re does not form clusters in γ(Ni), which is consistent with recent experiments and first-principles calculations.

Young's modulus of single-walled carbon nanotubes (SWCNTs) was calculated by a modern pseudo-potential ab initio method. Using different models for wall thickness, we found that the Young's modulus of an SWCNT varies in a wide range from 0.94 to 5.81 TPa. Here, an SWCNT's wall thickness was obtained by electronic structure calculation. Using the wall thickness, we obtained that the Young's modulus of an SWCNT is 1.06-1.16 TPa, which is in agreement with the experimental result of 1.20-1.25 TPa.

By using first-principles DMol and the discrete-variational method (DVM) based on density functional theory, we investigated the effect of some light impurities, H, B, C, N and O, on the electronic structure of their corresponding different impurity-doped systems in γ-TiAl. The impurity formation energy, Mulliken occupation, bond order and charge density difference have been calculated to study the impurity-induced changes in the energetics and electronic structure. According to the impurity formation energy, it is found that the impurities energetically prefer to occupy the Ti-rich octahedron interstitial sites in the order H