QUASI-PERIODIC FEATURES IN THE ATOMIC-STRUCTURE OF LONG-PERIOD GRAIN-BOUNDARIES

Atomic relaxations in grain boundaries (GBs) can assume quasiperiodic character even in periodic GBs, as we show for a SIGMA=41 GB in gold, which is analyzed by transmission-, high-resolution electron microscopy (HREM) and atomistic computer simulations. We find that misfit localization within a large planar GB unit cell can generate densely spaced regions of structural disorder, akin to misfit dislocations. The observations illustrate that atomic relaxations are typically dominated by short-range interactions and the tendency of the solid to assume a local atomic environment similar to the bulk.