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Title: Ultrahigh strain-rate bending of copper nanopillars with laser-generated shock waves

An experimental study to bend FIB-prepared cantilevered single crystal Cu nanopillars of several hundred nanometers in diameter and length at ultrahigh strain rate is presented. The deformation is induced by laser-generated stress waves, resulting in local strain rates exceeding 10{sup 7} s{sup −1}. Loading of nano-scale Cu structures at these extremely short loading times shows unique deformation characteristics. At a nominal stress value of 297 MPa, TEM examination along with selected area electron diffraction characterization revealed that twins within the unshocked Cu pillars interacted with dislocations that nucleated from free surfaces of the pillars to form new subgrain boundaries. MD simulation results were found to be consistent with the very low values of the stress required for dislocation activation and nucleation because of the extremely high surface area to volume ratio of the nanopillars. Specifically, simulations show that the stress required to nucleate dislocations at these ultrahigh strain rates is about one order of magnitude smaller than typical values required for homogeneous nucleation of dislocation loops in bulk copper single crystals under quasi-static conditions.
Authors:
 [1] ;  [2] ;  [3] ; ;  [1] ; ;  [1] ;  [4]
  1. Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, California 90095 (United States)
  2. (Colombia)
  3. Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, California 90095 (United States)
  4. (United States)
Publication Date:
OSTI Identifier:
22217786
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 23; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; BENDING; COPPER; DISLOCATIONS; ELECTRON DIFFRACTION; GRAIN BOUNDARIES; LASERS; MOLECULAR DYNAMICS METHOD; MONOCRYSTALS; NANOSTRUCTURES; NUCLEATION; SIMULATION; STRAIN RATE; SURFACE AREA; SURFACES; TRANSMISSION ELECTRON MICROSCOPY