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Article: Microstructural Stability of Fine-Grained Fully Lamellar XD TiAl Alloys by Step Aging
- Article from:
- Metallurgical and Materials Transactions
- Article date:
- May 1, 2005
- Author:
CopyrightCopyright Minerals, Metals & Materials Society May 2005. Provided by ProQuest LLC. (Hide copyright information)
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XD TiAl alloys (Ti-45 and 47Al-2Nb-2Mn + 0.8 vol pct TiB^sub 2^) (at. pct) were oil quenched to produce fine-grained fully lamellar (FGFL) structures, and aging treatments at different temperatures for different durations were carried out to stabilize the FGFL structures. Microstructural examinations show that the aging treatments cause phase transformation of α^sub 2^ to γ resulting in stabilization of the lamellar structure, as indicated by a significant decrease in α^sub 2^ volume fraction. However, several degradation processes are also introduced. After aging, within lamellar colonies, the α^sub 2^ lamellae become finer due to dissolution, whereas most of the γ ...