Effects of structural defects on strength and fracture properties of multi-walled carbon nanotubes

• TAMAKI Itaru

  Department of Environmental Studies for Advanced Society, Tohoku University

• SHIRASU Keiichi

  Fracture and Reliability Research Institute, Tohoku University

• MIYAZAKI Takamichi

  Technical Division Instrumental Analysis Group, School of Engineering, Tohoku University

• YAMAMOTO Go

  Department of Aerospace Engineering, Tohoku University

• BEKAREVICH Raman

  Department of Mechanical Engineering, Osaka University Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Material Science (NIMS)

• HIRAHARA Kaori

  Department of Mechanical Engineering, Osaka University

• SHIMAMURA Yoshinobu

  Department of Mechanical Engineering, Shizuoka University

• INOUE Yoku

  Department of Electronics and Material Science, Shizuoka University

• HASHIDA Toshiyuki

  Fracture and Reliability Research Institute, Tohoku University

Bibliographic Information

Other Title

• 多層カーボンナノチューブの強度・破壊特性評価と構造欠陥の影響に関する研究

Abstract

In this study, we report the relationship between the mechanical properties and structural defects of multi-walled carbon nanotubes (MWCNTs) synthesized by a chemical vapor deposition (CVD) method. The tensile strength, Young's modulus and Weibull modulus of the individual MWCNTs were determined by conducting uniaxial tensile tests using a manipulator tool operated inside a scanning electron microscope. In addition, the structural defects which induced the failure of the MWCNTs were observed by a transmission electron microscope (TEM). TEM observations revealed that the MWCNTs exhibited several types of structural defects: discontinuous flaws such as holes; kinks and bends; impurities i.e., catalysts even though highly crystalline layers were almost perfectly aligned with the MWCNT axis. The tensile-loading experiments demonstrated that the average tensile strength, Young's modulus and Weibull modulus of the 23 MWCNTs were 5.2 ± 2.1 GPa, 210 ± 140 GPa and 2.7, respectively. The MWCNTs underwent failure leaving either a clean break or a very short sword and sheath failure, suggesting that a significant interwall load transfer might be facilitated by the irregular wall structures as mentioned above. These mechanical characteristics and fracture modes were reasonably consistent with those of previously reported CVD-grown MWCNTs. In order to identify the structural defects controlling the fracture of the MWCNTs, structural analyses were conducted by comparing TEM images captured before and after their breaking. The TEM images of the individual MWCNTs revealed that the defects described above induced the nanotube failure. These suggest that the tensile strength of the CVD-grown MWCNTs used in this study is dominated by the structural defects in particular discontinuous flaws and kinks and bends. The results reported here indicate that improvement and optimization of synthesis methods are needed to prepare stronger MWCNTs with less structural defects reported here.

Journal

• Transactions of the JSME (in Japanese)

  Transactions of the JSME (in Japanese) 83 (847), 16-00283-16-00283, 2017

  The Japan Society of Mechanical Engineers

Keywords

• Carbon nanotube
• Tensile strength
• Young's modulus
• Weibull coefficient
• Structural defect

Details

• CRID: 1390282680493478016
• NII Article ID: 130006943707
• DOI: 10.1299/transjsme.16-00283
• ISSN: 21879761
• Web Site: https://www.jstage.jst.go.jp/article/transjsme/83/847/83_16-00283/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed