Creep mechanisms and interface-enhanced deformation twinning in a two-phase lamellar TiAl alloy [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1997.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 9 pages : digital, PDF file
- Additional Creators:
- Lawrence Livermore National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Deformation mechanisms and the role of interfaces in deformation twinning of a two-phase [TiAl(γ)/Ti₃Al(α₂)] lamellar alloy creep deformed at elevated temperatures have been investigated. Since the multiplication of lattice dislocations within both γ and α₂ lamellae is very limited at a low stress level due to a refined lamellar microstructure, the glide of interfacial dislocations on both γ/α₂ and γ/γ interfaces (i.e interface sliding) becomes an important deformation mode. Obstacles such as impinged lattice dislocations can impede the movement of interfacial dislocations, which glide in a cooperative fashion along the lamellar interfaces. The impediment of dislocation motion subsequently causes a dislocation pile-up in front of obstacles as creep strain accumulates. When the crystals deform at high stress level, deformation twinning becomes a predominant deformation mode. Deformation twins are found to nucleate from the interfaces as a result of a local stress concentration generated from dislocation pile-ups. It is suggested that the deformation twinning in lamellar TiAl/Ti₃Al crystals can be vieived as a stress relaxation process for the concentration of stress at the head of each dislocation pile-up. An interface-assisted twinning mechanism is accordingly proposed and discussed.
- Report Numbers:
- E 1.99:ucrl-jc--130082
E 1.99: conf-980716--
- Other Subject(s):
- Published through SciTech Connect.
3. Pacific Rim international conference on advanced materials and processing, Honolulu, HI (United States), 12-16 Jul 1998.
Hsiung, L.M., LLNL.
- Funding Information:
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