Relation between the microstructure and microchemistry in Ni‐based superalloy

Abstract

dNi-based superalloys with biphasic structure (g + g′) are widely used for high-temperature applications, such as disks and blades of gas turbines and aeronautical engines. For these applications, the stability at high temperature is of utmost importance, in particular the coarsening and the morphological changes of g′ may be seriously detrimental for in-service components. Evolution of g′ particles strongly depends on the composition difference between disordered matrix and particles. The present work is devoted to the investigation of the g′ morphology and the microchemistry in single crystal CM186LC superalloy in as-received condition and after creep. The study was carried out by scanning electron microscopy and atomic force microscopy, standard X-ray photoelectron spectroscopy and scanning photoemission microscopy (SPEM) at the ELETTRA synchrotron facility in Trieste. The difference in the chemical composition of two phases, g and g′, was revealed from the SPEM images and their spectral analysis. The structural evolution, taking place during creep and leading to rafting, seems to be determined not only by the external applied stress but also by W diffusion from g to g′ phase.

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…It was also observed that carbides precipitated near the fusion boundary. Kaciulis et al 11 examined the microstructure and microchemistry of nickel-based super alloys with biphasic structure (gamma and gamma 0 phases), using SEM, AFS, PIXE and scanning photoemission microscopy (SPEM). The compositional differences between the two phases were elucidated through SPEM spectral images.…”

Alloys for Aeronautic Applications: State of the Art and Perspectives

“…Refractory elements, such as Re, Ta, Ru and W, are today added to Ni-based superalloys to improve their high temperature properties [145][146][147][148]. These elements provide good creep strength because their low atomic mobility retards dislocation climb in both γ and γ' phases.…”

Welding of IN792 DS superalloy by electron beam

“…After the EBW, the microstructural features in the MZ, HAZ, and base alloy have been investigated by micro‐hardness tests, observations of light optical microscopy (LOM) and scanning electron microscopy (SEM), X‐ray diffraction (XRD), X‐ray Photoelectron Spectroscopy (XPS), and Auger electron spectroscopy (AES), which have already demonstrated their effectiveness in studies of composition profiles connected to diffusion phenomena in superalloys …”