Two different descriptions of the same grain boundary structure were considered. A bicrystal which contained a [101] tilt boundary was observed by means of weak-beam dark-field and high-resolution electron microscopy. Several weak-beam diffraction conditions confirmed the presence of a dense set of parallel dislocation lines that were spaced 1.9nm apart. The same spacing was found in high-resolution electron microscopic images. Two different descriptions of the grain boundary structure were presented. Each description of the grain boundary was better suited to analyzing the results from a given method. Due to the density of the grain-boundary defects, the deviation from exact coincidence approached the limit of validity of the Brandon criterion. The resolution limit of the weak-beam technique was almost reached. At the atomic scale of observation, 2-dimensional features were seen, and defects which had a direction that did not lie in the projected plane were not detected.

Structure of a [101] Tilt Grain Boundary in a Molybdenum Bicrystal. T.Vystavel, J.M.Pénisson, A.Gemperle: Materials Science Forum, 1999, 294-296, 259-62