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This content will become publicly available on July 23, 2019

Title: Shock-induced amorphization in silicon carbide

While silicon carbide (SiC) has been predicted to undergo pressure-induced amorphization, the microstructural evidence of such a drastic phase change is absent as its brittleness usually prevents its successful recovery from high-pressure experiments. In this paper we report on the observation of amorphous SiC recovered from laser-ablation-driven shock compression with a peak stress of approximately 50 GPa. Transmission electron microscopy reveals that the amorphous regions are extremely localized, forming bands as narrow as a few nanometers. In addition to these amorphous bands, planar stacking faults are observed. Large-scale non-equilibrium molecular dynamic simulations elucidate the process and suggest that the planar stacking faults serve as the precursors to amorphization. Finally, our results suggest that the amorphous phase produced is a high-density form, which enhances its thermodynamical stability under the high pressures combined with the shear stresses generated by the uniaxial strain state in shock compression.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [3] ;  [4] ; ORCiD logo [1]
  1. Univ. of California, San Diego, CA (United States)
  2. Univ. of California, San Diego, CA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
NA0002930; FG52-09NA29043; AC52-07NA27344; 09-LR-06-118456-MEYM; LFR-17-449059
Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 158; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Research Org:
Univ. of California, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Univ. of California (United States)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; silicon carbide; amorphization; laser shock compression
OSTI Identifier:
1462276