
AIMS Materials Science, 2017, 4(6): 12021219. doi: 10.3934/matersci.2017.6.1202
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Stress field of a nearsurface basal screw dislocation in elastically anisotropic hexagonal crystals
1 Department of Solid State Physics, Yerevan State University, 0025 Yerevan, Armenia
2 Almaz Synthesis LTD, 0069 Yerevan, Armenia
Received: , Accepted: , Published:
Topical Section: Crystalline Materials
The comparatively stronger effect of the elastic anisotropy on dislocationinduced stress distribution quantified for TiB_{2} is attributed to the higher degree of elastic anisotropy of this compound in comparison to that of the GaN. For GaN and TiB_{2}, the dislocation stress distribution maps are highly influenced by the free surface effect at “free surface–dislocation” distances roughly smaller than ≈15 and ≈50 nm, respectively. It is found that, for above indicated materials, the relative decrease of the force of interaction between nearsurface screw dislocations due to free surface effect is in the order Ti > GaN > TiB_{2} > Zn > Cd > Graphite that results from increase of the specific shear anisotropy parameter in the reverse order Ti < GaN < TiB_{2} < Zn < Cd < Graphite. The results obtained in this study are also applicable to the case when a screw dislocation is situated in the “thin film–substrate” system at a (0001) basal interface between the film and substrate provided that the elastic constants of the film and substrate are the same or sufficiently close to each other.
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