The effect of temperature and stress on mechanical twinning during creep deformation in TiAl

Conference · Sun Dec 31 00:00:00 EST 1995

OSTI ID:225171

Jin, Z ^[1]; Cheong, S W; Bieler, T R ^[2]

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1. Los Alamos National Lab., NM (United States). Materials Science and Technology Division
2. Michigan State Univ., East Lansing, MI (United States). Dept. of Materials Science and Mechanics

Tensile creep specimens deformed at different temperatures and stresses were investigated using transmission electron microscopy for the purpose of understanding mechanical twinning behavior during creep deformation in TiAl. Three types of mechanical twinning configurations, fine mechanical twins at grain triple points, parallel twinning (or lamellar refining) and cross twinning, are compared in the deformed specimens. More mechanical twins are observed in specimens deformed at 730 C than in the specimen deformed at 800 C, indicating that less mechanical twinning occurs during creep deformation at the higher temperature in TiAl. The respondence of mechanical twinning to the creep stress is contradictory to that to the temperature: the larger the applied creep stress, the more mechanical twinning occurs during creep deformation. A formation mechanism for fine mechanical twins and the competition between mechanical twinning and dislocation activation during creep deformation in TiAl are proposed based on the experimental observations.

• OSTI ID: 225171
• Report Number(s): CONF-950201-; ISBN 0-87339-304-X; TRN: IM9621%%101
• 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

Related Subjects

36 MATERIALS SCIENCE
TITANIUM ALLOYS
TWINNING
CREEP
ALUMINIUM ALLOYS
NIOBIUM ALLOYS
CHROMIUM ALLOYS
INTERMETALLIC COMPOUNDS
SAMPLE PREPARATION
CASTING
HOT PRESSING
HEAT TREATMENTS
CHEMICAL COMPOSITION
TRANSMISSION ELECTRON MICROSCOPY
LAMELLAE
TEMPERATURE DEPENDENCE
STRESSES
DEFORMATION
DISLOCATIONS
GRAIN BOUNDARIES