Characterization of [001] tilt boundaries in gold by high-resolution transmission electron microscopy

Selected [001] tilt boundaries in bicrystalline thin films of gold, corresponding to angles of misorientation ranging from 5° to 39°, have been examined by high-resolution transmission electron microscopy in order to characterize structure of low-angle, high-angle, and coincidence grain boundaries. Both bright-field and lattice-fringe images reveal that such boundaries are composed of a regular array of primary relaxations, with mean spacing identical to that of the O lattice, and a more widely spaced array of secondary relaxations, which accommodate small deviations from exact coincidence orientations. Results indicate that all tilt boundaries are characterized by a periodic structure, corresponding to primary relaxations between O-Lattice points. Moreover, primary and secondary relaxations occur concurrently near coincidence orientations.