α-NiPt(Al) and phase equilibria in the Ni–Al–Pt system at 1150 °C

The α-NiPt(Al) phase and its associated equilibria in the Ni–Al–Pt system at 1150 °C were investigated by analyzing equilibrated bulk alloys and the interdiffusion zones of diffusion couples. Phase constitutions, tie-lines and microstructures were determined using a combination of techniques, includ...

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Bibliographic Details
Published in:Acta materialia 2005-06, Vol.53 (11), p.3319-3328
Main Authors: Hayashi, S., Ford, S.I., Young, D.J., Sordelet, D.J., Besser, M.F., Gleeson, B.
Format: Article
Language:English
Subjects:
Applied sciences
Crystal structure
Exact sciences and technology
Metals. Metallurgy
Nickel aluminides
Phase equilibria
Platinum-group
Synchrotron radiation
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Summary:The α-NiPt(Al) phase and its associated equilibria in the Ni–Al–Pt system at 1150 °C were investigated by analyzing equilibrated bulk alloys and the interdiffusion zones of diffusion couples. Phase constitutions, tie-lines and microstructures were determined using a combination of techniques, including high-energy synchrotron X-ray diffraction, scanning electron microscopy and electron probe microanalysis. A large Pt solubility limit was found to exist in the β-NiAl, ∼42 at.%, and in γ′-Ni 3Al, ∼32 at.%. The α-NiPt(Al) phase was found to have wide Pt solubility range of about 33–60 at.% and to skew along an almost constant Pt/Al ratio of 1.5. The α-NiPt(Al) has an ordered face-centered tetragonal L1 0 crystal structure, with the Al and Pt atoms found to be preferentially located in the corners and prismatic faces, respectively. The temperature dependence of the lattice parameters and unit cell volume of the α phase were also determined.
ISSN:1359-6454
1873-2453
DOI:10.1016/j.actamat.2005.03.046