DIFFRACTION EFFECTS AND IMAGES FROM INCLINED GRAIN-BOUNDARIES IN POLYCRYSTALLINE THIN FOILS

The geometry of the reciprocal lattice associated with the periodic structure of inclined grain boundaries in thin foils is described. Electron diffraction effects consistent with the reciprocal lattice were observed from inclined boundaries. It is pointed out that, before any extra diffraction effects can be attributed to a periodic grain boundary structure, it is necessary to check for the possible contributions of double diffraction. Techniques for performing these checks were developed and applied to several boundaries observed in this study. The influence of grain boundary as well as spurious diffraction effects on the image of the boundary is described. Examples are discussed where the relationship between the image end the diffraction pattern is not straightforward. For boundaries containing relatively short-period structures, both the inclination of the boundary plane and the periodicity of the structure can be determined using diffraction techniques with little if any information required from the image. © 1979 Taylor & Francis Group, LLC.