TEM Characterization of Grain Boundaries in Mixed Bicrystal Films of Aluminum

The structure and faceting behavior of near-90° <110> tilt grain boundaries in thin films of aluminum with a unique mazed bicrystal geometry is characterized by conventional, high resolution and high-voltage electron microscopy. In this microstructure the absence of triple junctions allows grain boundaries to facet in optimum orientation (inclination) during annealing. The degree of anisotropy of the boundaries is expressed in the form of a rose plot. Small local deviations in misorientation are shown to be necessary to accommodate optimum boundary segments. The crystallographic symmetry inherent in this microstructure is apparent and utilized throughout the analysis.