材料期刊网

Electronic properties of the H- B- and C-doped gamma/gamma' 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 gamma/gamma' interface. The calculated charge transfer suggests that the effect of H, B and C on the gamma/gamma' 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 gamma/gamma' 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 gamma/gamma' interface.