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The structure of boron in boron fibresThe structure of noncrystalline, chemically vapour-deposited boron fibres was investigated by computer modelling the experimentally obtained X-ray diffraction patterns. The diffraction patterns from the models were computed using the Debye scattering equation. The modelling was done utilizing the minimum nearest-neighbour distance, the density of the model, and the broadening and relative intensity of the various peaks as boundary conditions. The results suggest that the fibres consist of a continuous network of randomly oriented regions of local atomic order, about 2 nm in diameter, containing boron atoms arranged in icosahedra. Approximately half of these regions have a tetragonal structure and the remaining half a distorted rhombohedral structure. The model also indicates the presence of many partial icosahedra and loose atoms not associated with any icosahedra. The partial icosahedra and loose atoms indicated in the present model are in agreement with the relaxing sub-units which have been suggested to explain the anelastic behavior of fibre boron and the loosely bound boron atoms which have been postulated to explain the strengthening mechanism in boron fibres during thermal treatment.
Document ID
19830063124
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Bhardwaj, J.
(TRW Inc. Carbide Tools Div., Rogers, AR, United States)
Krawitz, A. D.
(Missouri-Columbia, University Columbia, MO, United States)
Date Acquired
August 11, 2013
Publication Date
September 1, 1983
Publication Information
Publication: Journal of Materials Science
Volume: 18
ISSN: 0022-2461
Subject Category
Nonmetallic Materials
Accession Number
83A44342
Distribution Limits
Public
Copyright
Other

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