The role of boundary plane: HREM investigation of the atomic structure of grain boundaries in gold

Abstract

Computer simulations of large-angle grain boundaries (GBs) have indicated the importance of local atomic relaxation, rigid body translations, and of the boundary plane in determining GB energy. Experimental observations of GB structure often find GB faceting, which is an indication that some GB planes are preferred over others. Investigations of the atomic structure of large-angle >001> tilt GBs in NiO have shown, along with symmetrical GB con-figuations, the presence of asymmetric GBs of the type which has at least one of the crystals terminated at the boundary by a low index plane. Such boundaries are thought to be of low energy. For studying the role of the GB plane in a metallic GB we chose in the present work two <011> tilt boundaries in Au. The misorientation angles (θ) were selected such that one bicrystal orientation (θ=39°) was close to the Σ=9 reciprocal coincident site density, while the other (θ=55°) was near the misorientation for which (111) and (100) planes are parallel to each other (θ=54.74°). The latter misorientation is also close to Σ=41 (θ=55.88°).