Defect induced plasticity and failure mechanism of boron nitride nanotubes under tension

The effects of Stone-Wales (SW) and vacancy defects on the failure behavior of boron nitride nanotubes (BNNTs) under tension are investigated using molecular dynamics simulations. The Tersoff-Brenner potential is used to model the atomic interaction and the temperature is maintained close to 300 K....

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Bibliographic Details
Published in:Journal of applied physics 2014-07, Vol.116 (4)
Main Authors: Anoop Krishnan, N. M., Ghosh, Debraj
Format: Article
Language:English
Subjects:
Applied physics
Atomic interactions
Boron nitride
BORON NITRIDES
CHIRALITY
Computer simulation
CONFIGURATION
CRYSTAL DEFECTS
Defects
Dependence
Failure mechanisms
FAILURES
INTERACTIONS
Molecular dynamics
MOLECULAR DYNAMICS METHOD
NANOSCIENCE AND NANOTECHNOLOGY
NANOTUBES
PLASTICITY
PLASTICS
RELAXATION
SIMULATION
VACANCIES
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Summary:The effects of Stone-Wales (SW) and vacancy defects on the failure behavior of boron nitride nanotubes (BNNTs) under tension are investigated using molecular dynamics simulations. The Tersoff-Brenner potential is used to model the atomic interaction and the temperature is maintained close to 300 K. The effect of a SW defect is studied by determining the failure strength and failure mechanism of nanotubes with different radii. In the case of a vacancy defect, the effect of an N-vacancy and a B-vacancy is studied separately. Nanotubes with different chiralities but similar diameter is considered first to evaluate the chirality dependence. The variation of failure strength with the radius is then studied by considering nanotubes of different diameters but same chirality. It is observed that the armchair BNNTs are extremely sensitive to defects, whereas the zigzag configurations are the least sensitive. In the case of pristine BNNTs, both armchair and zigzag nanotubes undergo brittle failure, whereas in the case of defective BNNTs, only the zigzag ones undergo brittle failure. An interesting defect induced plastic behavior is observed in defective armchair BNNTs. For this nanotube, the presence of a defect triggers mechanical relaxation by bond breaking along the closest zigzag helical path, with the defect as the nucleus. This mechanism results in a plastic failure.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.4891519