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Title: A molecular dynamics study of tilt grain boundary resistance to slip and heat transfer in nanocrystalline silicon

We present a molecular dynamics study of grain boundary (GB) resistance to dislocation-mediated slip transfer and phonon-mediated heat transfer in nanocrystalline silicon bicrystal. Three most stable 〈110〉 tilt GBs in silicon are investigated. Under mechanical loading, the nucleation and growth of hexagonal-shaped shuffle dislocation loops are reproduced. The resistances of different GBs to slip transfer are quantified through their constitutive responses. Results show that the Σ3 coherent twin boundary (CTB) in silicon exhibits significantly higher resistance to dislocation motion than the Σ9 GB in glide symmetry and the Σ19 GB in mirror symmetry. The distinct GB strengths are explained by the atomistic details of the dislocation-GB interaction. Under thermal loading, based on a thermostat-induced heat pulse model, the resistances of the GBs to transient heat conduction in ballistic-diffusive regime are characterized. In contrast to the trend found in the dislocation-GB interaction in bicrystal models with different GBs, the resistances of the same three GBs to heat transfer are strikingly different. The strongest dislocation barrier Σ3 CTB is almost transparent to heat conduction, while the dislocation-permeable Σ9 and Σ19 GBs exhibit larger resistance to heat transfer. In addition, simulation results suggest that the GB thermal resistance not only depends on themore » GB energy but also on the detailed atomic structure along the GBs.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States)
  2. Department of Aerospace Engineering, Iowa State University, Ames, Iowa 50011 (United States)
  3. Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States)
Publication Date:
OSTI Identifier:
22399176
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPUTERIZED SIMULATION; CRYSTALS; DISLOCATIONS; GRAIN BOUNDARIES; LOADING; MOLECULAR DYNAMICS METHOD; NANOSTRUCTURES; NUCLEATION; PHONONS; SILICON; SLIP; THERMAL CONDUCTION; TRANSIENTS