First-Principles Study of the Electronic Properties of γ⁄γ′ Interface in Ni Based Superalloys

抄録

Electronic properties of the H-, B- and C-doped γ⁄γ′ interface in Ni based Superalloys are studied by means of the self-consistent full-potential linearized augmented-plane-wave method under generalized gradient approximation. It is shown that all the three impurities, H, B and C prefer to occupy the Ni-rich octahedral interstitial sites at the γ⁄γ′ interface. The calculated charge transfer suggests that the effect of H, B and C on the γ⁄γ′ interface is localized. For the B and C cases, due to the hybridization between the p states of the impurity and the d states of the nearest-neighbor nickel atoms, the effect of both B and C is to strengthen the γ⁄γ′ interface. In contrast, for the H case, the H-s/Ni-d hybridization results in a strong weakening of interplanar bonding and a slight enhancement of intraplanar Ni–Ni bonding on the interface planes, so that the effect of H is to decrease the cohesive strength of γ⁄γ′ interface.