Examination of dislocation structures near crack tip region of B2 NiAl alloys

Book · Wed Dec 31 04:00:00 EST 1997

OSTI ID:571798

Ng, B C; Simkin, B; Crimp, M A ^[1]

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1. Michigan State Univ., East Lansing, MI (United States). Dept. of Materials Science and Mechanics

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.

• Sponsoring Organization: Office of Naval Research, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
• OSTI ID: 571798
• Report Number(s): CONF-961202--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CRACKS
DISLOCATIONS
EXPERIMENTAL DATA
HEAT RESISTING ALLOYS
INTERMETALLIC COMPOUNDS
NICKEL ALLOYS