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Title: Directional amorphization of boron carbide subjected to laser shock compression

Solid-state shock-wave propagation is strongly nonequilibrium in nature and hence rate dependent. When using high-power pulsed-laser-driven shock compression, an unprecedented high strain rates can be achieved; we report the directional amorphization in boron carbide polycrystals. At a shock pressure of 45~50 GPa, multiple planar faults, slightly deviated from maximum shear direction, occur a few hundred nanometers below the shock surface. High-resolution transmission electron microscopy reveals that these planar faults are precursors of directional amorphization. We also propose that the shear stresses cause the amorphization and that pressure assists the process by ensuring the integrity of the specimen. Thermal energy conversion calculations including heat transfer suggest that amorphization is a solid-state process. Such a phenomenon has significant effect on the ballistic performance of B 4C.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [3] ;  [1]
  1. Univ. of California, San Diego, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. United States Army Research Lab., Aberdeen, MD (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-719797; DE-UCSD-NA0002080
Journal ID: ISSN 0027-8424
Grant/Contract Number:
AC52-07NA27344; 09-LR-06-118456; PE-FG52-09NA-29043
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 43; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; lasers; shock wave; amorphization; boron carbide
OSTI Identifier:
1328805
Alternate Identifier(s):
OSTI ID: 1361598; OSTI ID: 1462269