Thermodynamic stability and point defects of {gamma}-TiAl and the phase relationships of Ti-Al
- Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
Thermodynamic model parameters of the nine phases in the Ti-Al system were obtained by optimization using thermodynamic and phase equilibrium data existing in the literature. These phases are liquid, {alpha}-(Ti,Al), {beta}-(Ti,Al), (Al), {alpha}{sub 2}-Ti{sub 3}Al, {gamma}-TiAl, TiAl{sub 3}, TiAl{sub 2} and Ti{sub 2}Al{sub 5}. The Redlich-Kister equation was used to represent the excess Gibbs energy for the first four phases; the generalized quasi-chemical model recently formulated by them, for the next three phases; and the last two phases were treated as stoichiometric phases or line compounds. Thermodynamic values obtained from the model parameters as well as the calculated phase diagram are in agreement with the experimental data within the uncertainties of the data. The intrinsic defect concentrations obtained from the model parameters for {gamma}-TiAl are in accordance with values predicted from an independent relationship between the defect concentration and the enthalpy of formation. Since defect concentrations predicted from a similar relationship for anti-structure B2 phases are in accord with experimental values, it is reasonable to expect that the model-calculated values for {gamma}-TiAl are physically realistic.
- OSTI ID:
- 225083
- Report Number(s):
- CONF-950201-; ISBN 0-87339-304-X; TRN: IM9621%%13
- Resource Relation:
- Conference: Annual meeting and exhibition of the Minerals, Metals and Materials Society (TMS), Las Vegas, NV (United States), 12-16 Feb 1995; Other Information: PBD: 1995; Related Information: Is Part Of Gamma titanium aluminides; Kim, Y.W. [ed.] [UES, Inc., Dayton, OH (United States). Materials and Processes Div.]; Wagner, R. [ed.] [GKSS Research Center, Geesthacht (Germany). Inst. for Materials Research]; Yamaguchi, Masaharu [ed.] [Kyoto Univ. (Japan). Dept. of Materials Science and Engineering]; PB: 1023 p.
- Country of Publication:
- United States
- Language:
- English
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