Abstract
The fracture strengths and elastic moduli of arc-grown multi-walled carbon nanotubes (MWCNTs) were measured by tensile loading inside of a scanning electron microscope (SEM). Eighteen tensile tests were performed on 14 MWCNTs with three of them being tested multiple times (3×, 2×, and 2×, respectively). All the MWCNTs fractured in the "sword-in-sheath" mode. The diameters of the MWCNTs were measured in a transmission electron microscope (TEM), and the outer diameter with an assumed 0.34 nm shell thickness was used to convert measured load-displacement data to stress and strain values. An unusual yielding before fracture was observed in two tensile loading experiments. The 18 outer shell fracture strength values ranged from 10 to 66 GPa, and the 18 Young's modulus values, obtained from a linear fit of the stress-strain data, ranged from 620 to 1,200 GPa, with a mean of 940 GPa. The possible influence of stress concentration at the clamps is discussed.
Original language | English (US) |
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Pages (from-to) | 25-36 |
Number of pages | 12 |
Journal | Experimental Mechanics |
Volume | 47 |
Issue number | 1 |
DOIs | |
State | Published - Feb 2007 |
Externally published | Yes |
Funding
Acknowledgments We thank S. Mielke for comments. This work is supported by the National Science Foundation (NIRT Program, Grant No. 0304506, Dr. Ken P. Chong, Program Director) and by the NASA BIMat URETI # NCC-1-02037. The SEM (partially) and TEM work was performed in the EPIC facility of NUANCE Center which is supported by NSF-NSEC, NSF-MRSEC, Keck Foundation, the State of Illinois, and Northwestern University.
Keywords
- Fracture
- Modulus
- Nanotube
- Strength
- Yield
ASJC Scopus subject areas
- Aerospace Engineering
- Mechanics of Materials
- Mechanical Engineering