An Analytical Model for the Critical Shell Thickness in Core/Shell Nanowires Based on Crystallographic Slip
Employing crystal plasticity theory and micromechanics inclusion theory, we developed a full-strain relaxation model under isotropic assumption of materials properties to predict the dependence of the critical shell thickness (CST) for defect-free core/shell nanowires (NWs) on their growth direction. Unlike prior models, we consider three important factors in the energetic analysis (1) the self-energy of a dislocation loop in a finite domain, (2) the three-dimensional mismatch strains that develop in core/shell NWs (axial, radial and tangential directions) as a result of the finite NW geometry and the lattice mismatch between the core and shell materials, and (3) the three-dimensional plastic strains from misfit dislocations that nucleate to relax the mismatch strains. With these, the full-relaxation model is able to reveal that (i) the variation of the CST with growth direction depends on the core radius, (ii) misfit dislocations will not nucleate when the core radius falls below a critical value, (iii) the CST tends to a constant as the core radius increases, and (iv) the CST predicted by prior uniaxial-strain relaxation models is a lower bound.
H. Chu et al., "An Analytical Model for the Critical Shell Thickness in Core/Shell Nanowires Based on Crystallographic Slip," Journal of the Mechanics and Physics of Solids, vol. 61, no. 11, pp. 2147-2160, Elsevier Limited, Nov 2013.
The definitive version is available at http://dx.doi.org/10.1016/j.jmps.2013.07.004
Materials Science and Engineering
Keywords and Phrases
Core/shell Nanowires; Critical Shell Thickness; Crystalline Slip; Dislocations; Green's Function; Crystal Plasticity Theory; Energetic Analysis; Growth Directions; Relaxation Models; Shell Thickness; Tangential Directions
International Standard Serial Number (ISSN)
Article - Journal
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