Dislocation Structures in {01-12}/〈2-1-10〉 Low Angle Grain Boundary and Dissociation Reaction of 1/3〈02-21〉 Dislocation in α-Al<sub>2</sub>O<sub>3</sub>

Dislocation structures in the {0112}/⟨2110⟩ low-angle tilt grain boundary of α-Al2O3 were characterized by transmission electron microscopy. It was found that the grain boundary consists of dislocations with the Burgers vector of ⟨0110⟩, 1/3⟨1011⟩, and 1/3⟨0221⟩. These dislocations are dissociated into partial dislocations with stacking faults on the (0001) and/or {0110} planes. While the dissociation structures of the ⟨0110⟩ and 1/3⟨1011⟩ dislocations were consistent with previous reports, the 1/3⟨0221⟩ dislocation showed a characteristic V-shaped structure that had not been reported. This paper discusses the accommodation mechanism of the misorientation by the three types of dislocations and the dissociation structure of 1/3⟨0221⟩ in detail.