Promotion of topologically close-packed phases in a Ru-containing Ni-based superalloy

We report on the effects of Ru addition on the formation of topologically close-packed (TCP) phases in a Ni-based superalloy during high-temperature exposure. The Ru addition reduces the lattice misfit between the γ and TCP phase, unexpectedly promoting nucleation of the TCP phase. Furthermore, the γ matrix is destabilized by Ru, while the stability of TCP phase is less affected according to the prediction of an electronic structure map. The results of this work indicate that γ destabilization is another important factor for the role of Ru in TCP phase formation. Graphical Abstract .