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The dislocations contrast factors of cubic crystals in the Zener constant range between zero and unity

Published online by Cambridge University Press:  05 March 2012

I. C. Dragomir  and
T. Ungár
I. C. Dragomir
Affiliation:
Department of General Physics, Eötvös University Budapest, Pázmány Péter sétány 1/A, H-1518, P.O.B. 32, Budapest, Hungary
T. Ungár
Affiliation:
Department of General Physics, Eötvös University Budapest, Pázmány Péter sétány 1/A, H-1518, P.O.B. 32, Budapest, Hungary
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Abstract

Diffraction peak profiles broaden due to the smallness of crystallites and the presence of lattice defects. Strain broadening of powders of polycrystalline materials is often anisotropic in terms of the hkl indices. This kind of strain anisotropy has been shown to be well interpreted assuming dislocations as one of the major sources of lattice distortions. The knowledge of the dislocation contrast factors are inevitable for this interoperation. In a previous work the theoretical contrast factors were evaluated for cubic crystals for elastic constants in the Zener constant range 0.5≤Az≤8. A large number of ionic crystals and many refractory metals have elastic anisotropy, Az, well below 0.5. In the present work the contrast factors for this lower anisotropy-constant range are investigated. The calculations and the corresponding peak profile analysis are tested on ball milled PbS and Nb and nanocrystalline CeO2.

Keywords

contrast factorsdislocationspowder diffractionmicrostructureelastic anisotropy

Information

Type
Technical Articles
Information
Powder Diffraction , Volume 17 , Issue 2 , June 2002 , pp. 104 - 111
Copyright
Copyright © Cambridge University Press 2005

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