Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Influence of Atomic Size Factors on the Phase Stability of Laves Phase in Nb-Cr-Ni-Al and Nb-V-Ni-Al Phase Diagrams
Takuya YamanouchiSeiji Miura
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2018 年 59 巻 4 号 p. 546-555


Phase equilibria among the refractory bcc solid solution (bccss), B2, and Laves phases in Nb-Cr-NiAl and Nb-V-NiAl isothermal sections were studied with the aim of introducing the NiAl-B2 phase and/or Al-containing Laves phase for improvement of the oxidation resistance of the bccss phase as an Al reservoir layer for the Al2O3 surface layer. Laves phases appear in a wide composition range in both of the isothermal sections, which prevent equilibration of NiAl-B2 with the Nb-rich bccss phase. The geometrical model proposed by Edwards was applied to understand the site-substitution behavior of the multi-component AB2 Laves phase. In the Nb-Cr-NiAl, Nb-V-NiAl, and Nb-Mo-NiAl systems, the site-substitution behavior of the Laves phases could be explained by comparison of the average atomic diameters of NiAl-B2, Cr, V, and Mo.

© 2017 The Japan Institute of Metals and Materials
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