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Title: The influence of hold time on the onset of plastic deformation in silicon

The transformation of diamond-cubic silicon to the metallic β-Sn phase is known to be “sluggish,” even when the critical pressure (∼11 GPa) for the transformation is reached. In this letter, we use nanoindentation to apply pressures to just above the critical threshold. In this regime, the sample displays purely elastic behavior at zero hold time. As the hold time at maximum load is increased up to 180 s, the percentage of indents that plastically deform also increase. Interestingly, the indents deform via one of two distinct processes: either via a phase transformation to a mixed bc8/r8-Si end phase, or by initiation of crystalline defects. Raman spectroscopy and cross-sectional transmission electron microscopy are used to show that the two deformation mechanisms are mutually exclusive under the indentation conditions presented here, and elastic modelling was utilized to propose a model for this mutually exclusive behavior. Hence, this behavior enhances the potential for application of the exotic bc8/r8-Si end phase.
Authors:
 [1] ;  [2] ; ;  [3]
  1. Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia)
  2. Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37781 (United States)
  3. Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia)
Publication Date:
OSTI Identifier:
22493116
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CRITICAL PRESSURE; CRYSTAL DEFECTS; DEFORMATION; DIAMONDS; PHASE TRANSFORMATIONS; PLASTICITY; RAMAN SPECTROSCOPY; SILICON; TRANSMISSION ELECTRON MICROSCOPY