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This content will become publicly available on September 29, 2016

Title: Lattice-level observation of the elastic-to-plastic relaxation process with subnanosecond resolution in shock-compressed Ta using time-resolved in situ Laue diffraction

We report direct lattice level measurements of plastic relaxation kinetics through time-resolved, in-situ Laue diffraction of shock-compressed single-crystal [001] Ta at pressures of 27-210 GPa. For a 50 GPa shock, a range of shear strains is observed extending up to the uniaxial limit for early data points (<0.6 ns) and the average shear strain relaxes to a near steady state over ~1 ns. For 80 and 125 GPa shocks, the measured shear strains are fully relaxed already at 200 ps, consistent with rapid relaxation associated with the predicted threshold for homogeneous nucleation of dislocations occurring at shock pressure ~65 GPa. The relaxation rate and shear stresses are used to estimate the dislocation density and these quantities are compared to the Livermore Multiscale Strength model as well as various molecular dynamics simulations.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Atomic Weapons Establishment (AWE), Reading (United Kingdom)
  3. Riverside Research, Beavercreek, OH (United States)
Publication Date:
OSTI Identifier:
1242000
Report Number(s):
LLNL-JRNL--673957
Journal ID: ISSN 1098-0121; PRBMDO
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 10; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY