A dislocation model for flow at intermediate temperatures in hard-oriented NiAl

Book · Tue Aug 01 04:00:00 EDT 1995

OSTI ID:78353

Mills, M J ^[1]; Daw, M S ^[2]; Angelo, J E ^[3]; Miracle, D B ^[4]

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1. Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering
2. Clemson Univ., SC (United States). Dept. of Physics
3. Sandia National Labs., Livermore, CA (United States)
4. Air Force Wright Lab, Wright-Patterson AFB, OH (United States)

Recent studies of single crystals and bicrystals indicate that dislocations of the type a{l_angle}011{r_angle} are important, and may actually control, deformation at intermediate temperatures (above the brittle-to-ductile transition temperature) in hard-oriented NiAl. In the present work, the fine structure of a{l_angle}001{r_angle} dislocations has been examined using both high resolution and diffraction-contrast transmission electron microscopy. Evidence has been found for the decomposition of a{l_angle}011{r_angle} dislocations into two a{l_angle}001{r_angle} dislocations. The initial driving force for the decomposition is due to core effects, as revealed by molecular statics and dynamics Embedded Atom Method calculations. Additional decomposition occurs by a combination of climb and glide. A continuum-based dislocation model is introduced which incorporates these relevant microstructural features.

• Research Organization: Sandia National Laboratory
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 78353
• Report Number(s): CONF-941144--; ISBN 1-55899-265-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
DEFORMATION
DISLOCATIONS
EXPERIMENTAL DATA
HEAT RESISTING ALLOYS
MATHEMATICAL MODELS
NICKEL ALLOYS
THEORETICAL DATA