Deformation in {gamma}-titanium aluminides focused on anomalous hardening
- Polytechnic Univ., Brooklyn, NY (United States)
Anomalous deformation behavior of single phase gamma titanium aluminides be characterized with respect to their temperature dependence and strain rate dependence. The temperature dependent behavior may be better analyzed by dividing the yield stress curve into three distinct temperature regimes: Regime 1: normal soft mode from 4k to 273K; Regime 2: anomalous hardening mode from 273K to 873K or 1,073K and Regime 3: reverse hardening mode from 873K (or 1,073K) to 1,273K. The anomalous hardening regime may be again divided into two subregimes: Regime 2-1 characterized by weak hardening with the activation energy range of 0.037--49 eV and Regime 2-2, by strong hardening with the activation energy range of 0.13--14 eV. The former appears to be caused by octahedral locks in which the dislocation cores dissociate in the primary slip plane and subsequently, the superpartials cross-slip onto another octahedral plane. The cross slipped superpartials undergo dissociation into immobile Shockley partials and therefore, form octahedral locks as proposed. The latter is known to be caused by the K-W type mechanism. In Ti rich gamma phase, the K-W type hardening appears to be moderate due to the fact that the decomposition of superdislocations as a competing mechanism is active at or above RT.
- DOE Contract Number:
- FG02-93ER45499
- OSTI ID:
- 225096
- Report Number(s):
- CONF-950201-; ISBN 0-87339-304-X; TRN: IM9621%%26
- 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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