Structures of dissociated 1 1-bar 0 0 dislocations and {1 1-bar 0 0} stacking faults of alumina (alpha-Al_2O_3)

摘要

An alumina (alpha-Al_2O_3) bicrystal with a {1 1-bar 0 0}/ 2° low-angle grain boundary was fabricated by diffusion bonding, and the grain boundary was observed by high-resolution transmission electron microscopy (HRTEM). It was found that 1/3 partial-dis-location triplets were periodically arrayed along the boundary. The atomic structure within the {1 1-bar 0 0} stacking faults in between the partial-dislocation triplets was determined by HRTEM combined with first-principles calculations. We discuss the stacking fault struc-tures and their excess energies in detail.