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Examination of Dislocation Structures Near Crack TIP Region of B2 NiAl Alloys

Published online by Cambridge University Press:  15 February 2011

B-C. Ng ,
B. Simkin  and
M. A. Crimp
B-C. Ng
Affiliation:
Department of Materials Science and Mechanics, Michigan State University, MI 48824–1226, USA
B. Simkin
Affiliation:
Department of Materials Science and Mechanics, Michigan State University, MI 48824–1226, USA
M. A. Crimp
Affiliation:
Department of Materials Science and Mechanics, Michigan State University, MI 48824–1226, USA
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Abstract

The structure and distribution of dislocations in the region of crack tips and crack edges have been examined in single crystal stoichiometric B2 NiAl using electron channeling contrast imaging (ECCI). ECCI, which allows examination of near surface substructural crystalline defects in bulk specimens, has been carried out for undeformed as well as in-situ deformed 4-point bend specimens. Images of dislocations at crack tips and along the crack fracture surfaces have been studied. Observations have been correlated with variations in thermal treatment corresponding with brittle and toughened conditions. A higher dislocation density was observed over a larger region in front of crack tips for the toughened materials as compared to brittle material.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 460: Symposium Z – High-Temperature Ordered Intermetallic Alloys VII , 1996 , 387
Copyright
Copyright © Materials Research Society 1997

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References

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