Lattice misfit of high refractory ruthenium containing nickel-base superalloys

Abstract

The influence of Ru, Co, Mo and W on the lattice misfit of eight highly alloyed Re containing single crystal nickel-base superalloys was investigated. High resolution X-ray diffraction (XRD) was used to relate the elemental partitioning behavior and the Vegard coefficients of the elements under investigation to the measured lattice parameter of the γ and γ ́ phase. The residual chemical segregation and especially the coherency stress-induced tetragonal distortion of the γ matrix lattice in the high Mo containing alloys results in the observation of two different lattice parameters for the γ matrix phase. This leads to three overlapping, but clearly distinguishable {002} X-ray reflections. © (2011) Trans Tech Publications, Switzerland.