A dislocation model for flow at intermediate temperatures in hard-oriented NiAl
- Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering
- Clemson Univ., SC (United States). Dept. of Physics
- Sandia National Labs., Livermore, CA (United States)
- 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
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