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Ultrafine Fully-Lamellar Structures in Two-Phase γ-TiAl Alloys

Published online by Cambridge University Press:  15 February 2011

P. J. Maziasz  and
C. T. Liu
P. J. Maziasz
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831–6115, USA
C. T. Liu
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831–6115, USA
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Abstract

Special ultrafine fully-lamellar microstructures have been found recently in γ-TiAl alloys with 46–48 at.% Al, when they are processed or heat-treated above the α-transus temperature (Tα). Hot-extrusion above Tα also produces a refined colony or grain size. Refined-colony/ultrafine-lamellar (RC/UL) microstructures produce an excellent combination of room-temperature ductility and high-temperature strength in Ti-47Al-2Cr-2Nb (at.%) alloys. UL structures generally have an average interlamellar spacing of 100–200 nm, and have regularly alternating γ and α2 lamellea, such that they are dominated by γ/α2 interfaces with relatively few γ/γ twin boundaries. The focus of this study is how variations in processing parameters or alloy composition affect formation of the UL structure, particularly the α2 component.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 460: Symposium Z – High-Temperature Ordered Intermetallic Alloys VII , 1996 , 219
Copyright
Copyright © Materials Research Society 1997

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References

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