Simulation of plasticity in nanocrystalline silicon |
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| Authors: | M J Demkowicz A S Argon D Farkas M Frary |
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| Institution: | 1. MST-8: Structure–Property Relations Group, Los Alamos National Laboratory , Los Alamos, NM 87545, USA demkowicz@lanl.gov;3. Department of Mechanical Engineering , Massachusetts Institute of Technology , Cambridge, MA 02139, USA;4. Department of Materials Science and Engineering , Virginia Polytechnic Institute and State University , Blacksburg, VA 24061, USA;5. Department of Materials Science and Engineering , Boise State University , Boise, ID 83725, USA |
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| Abstract: | Molecular dynamics investigation of plasticity in a model nanocrystalline silicon system demonstrates that inelastic deformation localizes in intergranular regions. The carriers of plasticity in these regions are atomic environments, which can be described as high-density liquid-like amorphous silicon. During fully developed flow, plasticity is confined to system-spanning intergranular zones of easy flow. As an active flow zone rotates out of the plane of maximum resolved shear stress during deformation to large strain, new zones of easy flow are formed. Compatibility of the microstructure is accommodated by processes such as grain rotation and formation of new grains. Nano-scale voids or cracks may form if stress concentrations emerge which cannot be relaxed by a mechanism that simultaneously preserves microstructural compatibility. |
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