Climb dissociation of 〈1010〉 dislocations in sapphire (α-Al₂O₃)

Abstract

l O i O > dislocation loops are formed from edge dipoles during the early stages of prismatic slip in sapphire (a-A1203). These loops are predominantly edge in character and dissociate by climb into triplets of concentric loops with b = +<IOTO>.These faulted loops lie on { l l Z O } prismatic planes. As the loops shrink by bulk diffusion, they transform to doubly-dissociated faulted loops and then to single faulted loops. The cation fault produced in all these reactions is identicai with that previously reported for the glide dissociation of the <lOTO) dislocations. The stacking fault energies inferred from the mean radii and extents of dissociation observed are in agreement with the range of those previously reported.