Structure of the 〈0110〉 dislocation in sapphire
- 1 June 1976
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine
- Vol. 33 (6) , 877-889
- https://doi.org/10.1080/14786437608221921
Abstract
Experimental evidence of the existence of 〈01 0〉 dislocations in the {2 0} prism planes in sapphire has been obtained by transmission electron microscopy. By the weak-beam technique it has been shown that the 〈01 0〉 dislocations may dissociate into three partials. The partials all have a Burgers vector of ⅓ 〈01 0〉 and are separated by two identical faults. The distance between two partials is in the range 75-135 Å, corresponding to a fault energy of 320±60 mJ/m2. Perfect 〈01 0〉 dislocations have also been observed. These dislocations exhibited either one or two peaks when imaged in the (03 0) reflection by the weak-beam technique. The interpretation of the electron micrographs has been supported by computer simulation of the dislocation images. A faulted dipole has been observed, indicating that some of the prismatic loops often seen to lie in rows along [0001] are faulted with a ⅓ 〈01 0〉 Burgers vector. A mechanism for the dipole formation is suggested.Keywords
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