The structure of interfacial disconnections (i.e. line defects possessing both step and dislocation character) at a 90° <110> tilt boundary in Au was investigated. High-resolution transmission electron microscopy observations identify these defects separating short (40-60Å) <111>-<112> terraces along the boundary. Because the ratio of the periodic length in the <111> direction to that in the <112> direction was irrational (2½), the crystallography of this boundary was incommensurate. By measuring the dislocation content of the disconnections, it was shown how the defects accommodate the 5.7% 'misfit' in the directions parallel to the interface and thereby enable coherency to be achieved across the <111>-<112> terraces. This structural relaxation was markedly different from that at <100>-<110> grain boundary facets in this same system, for which previous observations have found an incoherent structure with no strain localization.

Accommodation of Coherency Strain by Interfacial Disconnections at a 90° <110> Grain Boundary in Gold. D.L.Medlin, D.Cohen, R.C.Pond: Philosophical Magazine Letters, 2003, 83[4], 223-32