EPRI-2013 ManuscriptASuzuki Final.pdf (374.23 kB)
Download fileFormation of diffusion zones in coated Ni-Al-X ternary alloys and Ni-based superalloys
conference contribution
posted on 2014-03-12, 15:06 authored by A.S. Suzuki, Geoff West, Rachel ThomsonRachel ThomsonCoatings are an essential part of the materials system to protect the turbine blades from oxidation
and corrosive attack during service. Inter-diffusion of alloying elements between a turbine blade
substrate and their coatings is a potential concern for coated turbine blades at ever increasing
operating temperatures because this can cause the formation of undesirable Secondary Reaction
Zones (SRZs), which may degrade the mechanical properties of coated Ni-based superalloys.
Understanding the effects of each element on the SRZ formation is essential in order to
understand both the mechanism and inter-diffusion behaviour between coatings and substrates. In
this research, a number of simpler aluminized ternary Ni-Al-X (where X is Co, Cr, Re, Ru or Ta)
alloys were investigated in order to elucidate the separate effects of each element on the
microstructural evolution, especially at the coating/substrate interface. The aluminized ternary
alloys developed distinctive diffusion zones, depending on the third alloy element, ‘X’.
Specifically, it has been found that both Ni-Al-Re and Ni-Al-Ta alloys developed a continuous
SRZ-like diffusion layer. This diffusion zone persisted in the Ni-Al-Re alloys after high
temperature exposure, indicating that Re has a stronger effect on SRZ formation than Ta.
Funding
This research was supported by the Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowship for Research Abroad scheme and the Department of Materials, Loughborough University.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials