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The Stability of the T2 (AL6CuLi3) Phase During Examination in the Tem

Published online by Cambridge University Press:  28 February 2011

A. S. Ramani ,
M. H. Tosten ,
C. W. Bartges ,
D. J. Michel ,
J. R. Reed ,
E. R. Ryba  and
P. R. Howell
A. S. Ramani
Affiliation:
Department of Materials Science and Engineering, The Pennsylvania State University, PA 16802
M. H. Tosten
Affiliation:
Now with Westinghouse Savannah River Laboratory, Aiken, SC 29808, USA
C. W. Bartges
Affiliation:
Now with the Alloy Technology Division, Alcoa Laboratories, PA 15681
D. J. Michel
Affiliation:
Material Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375.
J. R. Reed
Affiliation:
Material Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375.
E. R. Ryba
Affiliation:
Department of Materials Science and Engineering, The Pennsylvania State University, PA 16802
P. R. Howell
Affiliation:
Department of Materials Science and Engineering, The Pennsylvania State University, PA 16802
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Abstract

Transmission electron microscopy (TEM) has been employed to examine the stability of the (presumed) icosahedral T2 (A16 Cu Li3) phase. The T2 phase was found to be unstable either when irradiated by the electron beam or during in-situ heating. In addition, certain specimen preparation techniques (e.g., ion-beam thinning) also led to the decomposition of the T2 phase. When the T2 particles were formed during conventional aging of aluminum-rich Al-Li-Cu based alloys, the transformation products were invariably microcrystalline. Individual microcrystals have been identified as the aluminum rich ∝-solid solution which, in certain instances, contained the δʹ (Al3Li) phase. TB (A17.5 Cu4Li) and T1 (Al2CuLi) particles were also found. When the T2 phase was prepared by casting alloys of the proposed stoichiometry of T2, then the transformation products were more complex, although certain reaction products have been identified as the a solid solution, TB and T1.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 186: Symposium I – Alloy Phase Stability and Design , 1990 , 433
Copyright
Copyright © Materials Research Society 1991

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References

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