By using a first-principles method, based upon density functional theory, an investigation was made of the alloying effect of refractory elements such as Ta and W in the a/2[110](001) misfit dislocation core of the γ/γ′ interface in single-crystal Ni-based superalloys. The energetic calculations showed that both of the refractory elements could stabilize the a/2[110](001) misfit dislocation core. Analysis of the electronic structure indicated that there was charge accumulation between the refractory impurity atom and the neighboring Ni atoms, and that the strong bonds between refractory impurities and Ni atoms were due mainly to the hybridization of impurity d-Ni d orbitals. The introduction of the 2 refractory impurities resulted in a strong pinning effect upon a/2[110](001) misfit dislocation motion in the γ/γ′ interface.

First-Principles Investigation of the Alloying Effect of Refractory Elements Ta and W in the Misfit Dislocation Core of γ/γ′ (001) Interface. C.Y.Geng, C.Y.Wang, T.Yu: Physica B, 2005, 358[1-4], 314-22