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On Grain Boundary Dislocation Contrast in the Electron Microscope

  • R. W. Balluffi
  • G. R. Woolhouse
  • Y. Komem

Abstract

Grain boundary dislocations (GBD’s) may be studied conveniently in the electron microscope using specimens which are prepared by welding together two single crystal films having predetermined orientations to produce a thin-film bicrystal slab containing any type of grain boundary. The boundary is then examined at normal incidence. Problems associated with the imaging of GBD’s in both low and high angle boundaries of this type are considered. The following main topics are discussed from both the theoretical and experimental standpoints: (1) the strain field diffraction contrast produced by isolated screw and edge GBD’s under relatively simple conditions where no more than two strong beams exist in the upper crystal, and no more than four strong beams exist in the lower crystal; (2) the effects of superimposed Moiré patterns which are formed when more than one beam enters the objective aperture; (3) the diffraction contrast produced by regular arrays of closely spaced GBD’s and the problem of resolving individual GBD’s in such arrays; and (4) evidence that regular arrays of GBD’s act as twodimensional diffraction gratings which produce extra diffraction spots which may be of use in the direct imaging of finely spaced arrays.

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Copyright information

© American Institute of Mining, Metallurgical and Petroleum Engineers, Inc. 1972

Authors and Affiliations

  • R. W. Balluffi
    • 1
  • G. R. Woolhouse
    • 2
  • Y. Komem
    • 3
  1. 1.Department of Materials Science & EngineeringCornell UniversityIthacaUSA
  2. 2.University of CambridgeCambridgeEngland
  3. 3.Technion-Israel Institute of TechnologyHaifaIsrael

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