The study of the structure of grain boundaries using diffraction techniques

The development and use of electron and X-ray diffraction techniques to study the structure of grain boundaries in crystalline materials is reviewed. The fundamental questions that need to be answered about the structure of boundaries are discussed. The scattering expected from a small-angle twist boundary is calculated and shown to be in good agreement with electron and X-ray diffraction observations. The recent results from X-ray studies on large-angle twist and tilt boundaries in specially prepared Au bicrystals are examined and used to illustrate the type of information that diffraction techniques can provide on the detailed atomic structure of grain boundaries. It is also shown that electron diffraction can be used to examine the structure of grain boundaries of polycrystalline specimens.