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AIMS Materials Science, 2017, 4(6): 1202-1219. doi: 10.3934/matersci.2017.6.1202
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Stress field of a near-surface 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 dislocation-induced stress distribution quantified for TiB2 is attributed to the higher degree of elastic anisotropy of this compound in comparison to that of the GaN. For GaN and TiB2, 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 near-surface screw dislocations due to free surface effect is in the order Ti > GaN > TiB2 > Zn > Cd > Graphite that results from increase of the specific shear anisotropy parameter in the reverse order Ti < GaN < TiB2 < 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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