Nanotwinned Boron Suboxide (B6O): New Ground State of B6O

Qi An, K. Madhav Reddy, Huafeng Dong, Ming Wei Chen, Artem R. Oganov, William A. Goddard

    Research output: Contribution to journalArticlepeer-review

    28 Citations (Scopus)

    Abstract

    Nanotwinned structures in superhard ceramics rhombohedral boron suboxide (R-B6O) have been examined using a combination of transmission electron microscopy (TEM) and quantum mechanics (QM). QM predicts negative relative energies to R-B6O for various twinned R-B6O (denoted as -B6O, 2-B6O, and 4-B6O), consistent with the recently predicted B6O structure with Cmcm space group (-B6O) which has an energy 1.1 meV/B6O lower than R-B6O. We report here TEM observations of this -B6O structure, confirming the QM predictions. QM studies under pure shear deformation and indentation conditions are used to determine the deformation mechanisms of the new -B6O phase which are compared to R-B6O and 2-B6O. The lowest stress slip system of -B6O is (010)/«001» which transforms -B6O to R-B6O under pure shear deformation. However, under indentation conditions, the lowest stress slip system changes to (001)/«110», leading to icosahedra disintegration and hence amorphous band formation.

    Original languageEnglish
    Pages (from-to)4236-4242
    Number of pages7
    JournalNano Letters
    Volume16
    Issue number7
    DOIs
    Publication statusPublished - 2016 Jul 13

    Keywords

    • DFT
    • Superhard ceramics
    • deformation mechanism
    • stacking faults energy

    ASJC Scopus subject areas

    • Bioengineering
    • Chemistry(all)
    • Materials Science(all)
    • Condensed Matter Physics
    • Mechanical Engineering

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