Evaluation of phase relations in the Nb-Cr-Al system at 1000 degree C using a diffusion-multiple approach

A high-efficiency diffusion-multiple approach was used to map most of the phase relations of the Nb-Cr-Al ternary system at 1000 degree C. This system is very valuable for the design of niobium silicide-based composites. These composites have high potential as a replacement for Ni-base superalloys f...

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Bibliographic Details
Published in:Journal of phase equilibria and diffusion 2004-04, Vol.25 (2), p.152-159
Main Authors: Zhao, J-C, Jackson, M R, Peluso, LA
Format: Article
Language:English
Subjects:
Aluminum
Chromium
Design engineering
Diffusion
Electron back scatter diffraction
Laves phase
Niobium
Oxidation resistance
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Summary:A high-efficiency diffusion-multiple approach was used to map most of the phase relations of the Nb-Cr-Al ternary system at 1000 degree C. This system is very valuable for the design of niobium silicide-based composites. These composites have high potential as a replacement for Ni-base superalloys for jet engine applications. Both Cr and Al are alloying elements for these composites; thus the Nb-Cr-Al phase diagram, especially the stability of the oxidation-resistant Laves phase, is important information for the composite design. A partial 1000 degree C isothermal section was constructed from the results obtained using electron probe microanalysis (EPMA) and electron backscatter diffraction (EBSD) from a diffusion multiple made up of Nb, Cr, NbAl sub(3), and NbSi sub(2). The stabilization of the C14 Laves phase by Al dominates the 1000 degree C isothermal section, and the solubility of Al in the C14 Laves phase is as high as 45 at.%.
ISSN:1547-7037
1863-7345
DOI:10.1007/s11669-004-0008-x