Abstract
? 2022 Elsevier B.V.The synchrotron radiation X-ray absorption fine structure (XAFS) technique is used to study the local structure of the key atom Ru in a series of Ni-Al-Ru ternary alloys with different Ru contents and heat treatments. All the investigated alloys consist of two phases, γ and γ', and especially Ru exists as an atom coordinated by 12 Ni atoms in the first shell without Ru clusters or intermetallic compounds. In γ phase Ru resides on the Ni lattice site introducing an outward relaxation of the neighboring atoms, while in the γ' phase Ru replaces the Al lattice site causing an inward relaxation. The interatomic distance of Ru–Ni bond and Debye-Waller factor are mainly affected by the composition and increase with the increasing Ru content. While the effect of heat treatment is obvious when the Ru content is higher than 6 at%. The variation of Ru local atomic structure can greatly influence the microstructural evaluation and deformation mechanism by changing the lattice misfit and the vacancy formation energy to control the creep properties of Ni-Ru-Al ternary alloys.
NSTL
Elsevier