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APS » Journals » Phys. Rev. Lett. » Volume 102 » Issue 7
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Phys. Rev. Lett. 102, 075505 (2009) [4 pages]

Depressurization Amorphization of Single-Crystal Boron Carbide

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X. Q. Yan1,2, Z. Tang3, L. Zhang1, J. J. Guo1, C. Q. Jin4, Y. Zhang2, T. Goto5, J. W. McCauley6, and M. W. Chen1,5,*
1WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
2Department of Materials Physics and Chemistry, University of Science & Technology Beijing, Beijing 100083, China
3Key Laboratory of Polar Materials and Devices, East China Normal University, Shanghai 200062, China
4Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
5Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
6U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA

Received 26 July 2008; published 20 February 2009

We report depressurization amorphization of single-crystal boron carbide (B4C) investigated by in situ high-pressure Raman spectroscopy. It was found that localized amorphization of B4C takes place during unloading from high pressures, and nonhydrostatic stresses play a critical role in the high-pressure phase transition. First-principles molecular dynamics simulations reveal that the depressurization amorphization results from pressure-induced irreversible bending of C-B-C atomic chains cross-linking 12 atom icosahedra at the rhombohedral vertices.

© 2009 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.102.075505
DOI:
10.1103/PhysRevLett.102.075505
PACS:
61.50.Ks, 07.35.+k, 78.30.−j, 82.40.Fp

*Corresponding author: mwchen@imr.tohoku.ac.jp

 
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