Climb dissociation of dislocations in sapphire (α-Al2O3) revisited: Crystallography of dislocation dipoles
- 1 March 1982
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine A
- Vol. 45 (3) , 371-385
- https://doi.org/10.1080/01418618208236177
Abstract
Dislocation dipoles formed during high-temperature basal slip in sapphire (α-Al2O3) are unstable and break up by several different climb processes. Dipoles with perfect 1/3 Burgers vector can break up by successive pinching-off of their ends to produce strings of loops. Alternatively, the dipoles can break up into faulted loops and dipoles by climb dissociation into 1/3 partials; these faulted dipoles are first formed on {1210} prism planes and subsequently rotate into their new edge orientation on the {1100} prism planes. All faulted rotated dipoles are of interstitial character, suggesting that the faults produced by vacancy and interstitial dipoles have a different structure, and hence a different energy. Free dislocations are also dissociated by climb; the separation distance of the partials suggests a fault energy of 0.2 J/m2. Dissociation by glide has not been observed.Keywords
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