Climb dissociation of dislocations in sapphire (α-Al2O3)
- 1 September 1976
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine
- Vol. 34 (3) , 441-451
- https://doi.org/10.1080/14786437608222034
Abstract
Edge dislocation dipoles, formed in sapphire during basal glide at elevated temperatures, break up into strings of loops by self-climb. One stage in this process is the transformation of narrow dipoles into faulted dipoles. This is due to the climb dissociation of each dislocation in the dipole, according to the reaction 1/3[11 0]→1/3[11 0] + 1/3[01 0], with one pair of partials annihilating to form the faulted dipole. The stacking fault energy is estimated to be ∼400 erg/cm2, based on the maximum width of the faulted dipoles. A second stage, where the faulted dipoles rotate through 30° to the exact edge orientation, occurs to reduce the elastic energy.Keywords
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