Analysis of dislocation wall formation in a disclinated nanograin |
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Authors: | M.S. Wu |
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Affiliation: | School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore |
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Abstract: | Disclinations are common defects in nanocrystalline materials processed via the severe plastic deformation technique. A disclination, depending on its strength, may remain stable or partially relax into other structures such as cracks and dislocation walls. This paper develops closed-form analytical expressions for the energy of a nanograin containing a negative wedge disclination and a wall of periodic edge dislocations. Using these expressions, it is found that (1) a critical disclination strength is required for emitting dislocations and that this critical value demonstrates a strong power law dependence on the nanograin size, (2) there exists a favorable dislocation spacing, which decreases with increase in the disclination strength, in the dislocation wall formed by the emitted dislocations, and (3) the misorientation of the dislocation wall lies between 5° and 12° for disclination strength in the range of 15–35°. |
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Keywords: | Disclination Dislocation wall formation Nanograin Strain energy |
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