Basal Slip in Sapphire

Prism-plane slip occurs by the motion of (lOlO) dislocations on the 1210 plane, rather than 1 /3 (1210) dislocations in the lOlO plane, in spite of the unusually large magnitude of the Burgers vector of (lOlO) dislocations. Such dislocations 

This reaction can occur by glide in the basal plane only for screw dislocations, and is thought to be the mechanism for the formation of a dislocation network in crystals undergoing deformation by prism plane slip [97]. Alternatively, the dislocation can lower its energy by dissociating into three collinear partials according to the reaction (see also Table 9.3)  

This dissociation has been observed to occur by climb for high-temperature deformation, but can also occur by glide. 

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Suggest an energetically favorable dislocation reaction for the splitting of a unit dislocation into partial dislocations for basal slip in sapphire (a-alumina) single crystals. 

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