Coarsening behavior of lamellar structure in Ti-(40-47)Al(at.%) alloy
- National Inst. of Standards and Technology, Gaithersburg, MD (United States). Metallurgy Division
Coarsening behavior of a Ti{sub 3}Al ({alpha}{sub 2})/TiAl({gamma}) lamellar structure has been studied for binary Ti-Al alloys containing 40, 44 and 47 at.%Al, at temperatures ranging from 1,173 to 1,323 K. The morphologies of the discontinuous coarsening at initial and advanced stages were investigated using optical and transmission electron microscopy. The microstructural and thermal factors affecting growth kinetics of discontinuous coarsening were analyzed based on the theoretical rate equation derived by Livingston and Cahn. The measured growth velocity of discontinuously coarsened grains agreed qualitatively with the theoretical one calculated using measured microstructural parameters. The formation of grain boundary allotriomorphs appeared to play an important role for initiation of the discontinuous coarsening in the alloys studied. Lamellae with many imperfections such as lamellar termination, branching and curved lamellar interfaces were observed in the secondary lamellae. These microstructural features were characterized and discussed.
- OSTI ID:
- 225089
- Report Number(s):
- CONF-950201--; ISBN 0-87339-304-X
- Country of Publication:
- United States
- Language:
- English
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