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Metastable Extensions of Intermediate Phases in Some Aluminum - Rare-Earth Metal Systems

Published online by Cambridge University Press:  25 February 2011

M.X. Quan
Affiliation:
Materials Science Division, Barnett Institute and Department of Chemistry, Northeastern University, Boston, MA
P. Haldar
Affiliation:
Materials Science Division, Barnett Institute and Department of Chemistry, Northeastern University, Boston, MA
J. Werth
Affiliation:
Materials Science Division, Barnett Institute and Department of Chemistry, Northeastern University, Boston, MA
B.C. Giessen
Affiliation:
Materials Science Division, Barnett Institute and Department of Chemistry, Northeastern University, Boston, MA
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Abstract

Using the arc-furnace hammer-and-anvil method, metastable alloys in the Al-rich portions of four Al-RE systems (10-30 at. pct. RE; Re = Gd, Ho, Er and Y) were prepared and examined by XRD. The principal results are: all equilibrium alloy phases [Al4RE (T phase), Al3RE (CN12 close-packed phases) and Al2RE (Laves phase)] have substantial metastable solid solubilities for excess Al; e.g., in the Al-Y system, L phase is extended from 66.7 up to 86 at. pct. Al, suppressing any formation of the Al3RE phase in that system.

For early RE elements up to and including Gd, T phase is favored; for alloy chemically intermediate RE elements such as Y, L phase is dominant and for late RE elements (after Ho), the CP phases are extended most. DSC work indicates the formation of additional metastable phases occurring during equilibration.

Type
Research Article
Copyright
Copyright © Materials Research Society 1986

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Footnotes

*

Communication No. 281 from the Barnett Institute

References

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