Atomic relaxation modes in grain boundaries

Abstract

High-resolution electron microscopy (HREM) in combination with computer simulations of the fully relaxed atomic structures and energies of symmetric and asymmetric grain boundaries (GBs) in Au <110> tilt bicrystals has been applied to a study of atomic relaxation modes. These investigations indicate that: (1) 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. (2) Misfit localizations are likely within a structural unit whenever the GB unit cell is large. (3) When there is a length mismatch along the GB the atomic relaxations can assume quasiperiodic character, generating densely spaced regions of structural disorder, akin to misfit dislocations. (4) Atomic relaxations can take the form of stacking disorder