High-resolution electron microscopy of dislocation cores in NiAl

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20001670

Stoeckle, D; Sigle, W; Seeger, A

The atomic structure of dislocation cores in NiAl is studied by high-resolution transmission electron microscopy (HRTEM) and molecular dynamics (MD) calculations. Results are presented on dislocations with Burgers vectors b = a{lt}100{gt} and a{lt}111{gt}. A comparison of HRTEM image simulations indicates that the core of a 45{degree} a{lt}100{gt} dislocation consists of Al atoms. The Burgers vector distribution shows a width of 2.2b. This corresponds very closely to MD results and is consistent with the relatively low Peierls stress of this dislocation. By detailed image analysis the angular dependence of the shear stress components of the dislocation are made visible. MD results obtained from 45{degree} dislocations with opposite screw components suggest, that the helicity of the screw component might be discernible from high-resolution electron micrographs. A a{lt}111{gt} dislocation with {l{underscore}angle}110{r{underscore}angle} line direction is shown which exhibits a rather wide dissociation, probably into two a/2{lt}111{gt} partials.

• Research Organization: Max-Planck-Inst. fuer Metallforschung, Stuttgart (DE)
• OSTI ID: 20001670
• Report Number(s): CONF-981104--; ISBN 1-55899-458-0; ISSN 1067-9995
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
BURGERS VECTOR
DEFORMATION
DISLOCATIONS
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
INTERMETALLIC COMPOUNDS
MICROSTRUCTURE
MOLECULAR DYNAMICS METHOD
MONOCRYSTALS
NICKEL ALLOYS