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A Dislocation Model for Flow at Intermediate Temperatures in Hard-Oriented NiAl

Published online by Cambridge University Press:  22 February 2011

M. J. Mills ,
M. S. Daw ,
J.E. Angelo  and
D. B. Miracle
M. J. Mills
Affiliation:
Dept. of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210
M. S. Daw
Affiliation:
Dept. of Physics, Clemson University, Clemson, SC 29634–1911
J.E. Angelo
Affiliation:
Sandia National Laboratories, Livermore, CA 94551-0969
D. B. Miracle
Affiliation:
Air Force Wright Laboratory, WPAFB, OH 45433.
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Abstract

Recent studies of single crystals and bicrystals indicate that dislocations of the type a<011> 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<011> dislocations has been examined using both high resolution and diffraction-contrast transmission electron microscopy. Evidence has been found for the decomposition of a<011> dislocations into two a<001> 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.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 364: Symposium L – High-Temperature Ordered Intermetallic Alloys–VI , 1994 , 401
Copyright
Copyright © Materials Research Society 1995

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