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First-principles study of deformation-induced phase transformations in Ti–Al intermetallics

Published online by Cambridge University Press:  31 January 2011

L.L. He*
Affiliation:
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
H.Q. Ye
Affiliation:
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; and Electron Microscope Laboratory, Peking University, Beijing 100871, China
*
a) Address all correspondence to this author. e-mail: llhe@imr.ac.cn
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Abstract

The structural phase stability and electronic properties of the Ti–Al intermetallic compounds were investigated by means of density-functional theory (DFT) calculations in a generalized gradient approximation. Through comparison of the calculated formation energies of the parent and product phases, an in-depth theoretical understanding of the deformation-induced γ ↔ α2 phase transitions observed previously in TiAl alloys was achieved. The formation energy plays an important role in evaluating the feasibility of these phase transformations during plastic deformation of TiAl alloys. In addition, the density of states (DOS) was also calculated and used to analyze the stability of Ti–Al intermetallic compounds. The reasons for the absence of the deformation-induced (DI)-α2 and DI-γ (L12) phases in underformed TiAl alloys were analyzed.

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Articles
Copyright
Copyright © Materials Research Society 2009

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