Open Access

ARTICLE

Toughening Mechanisms in Carbon Nanotube-Reinforced Amorphous Carbon Matrix Composites

J.B. Niu¹, L.L. Li², Q. Xu¹, Z.H. Xia^1,3

1 Department of Materials Science and Engineering, University of North Texas, Denton, TX 76203, USA.
2 School of Materials Science and Engineering, Fujian University of Technology, Fuzhou 350108, China.
3 Department of Chemistry, University of North Texas, Denton, TX 76203, USA.

Computers, Materials & Continua 2013, 38(1), 31-41. https://doi.org/10.3970/cmc.2013.038.031

Abstract

Crack deflection and penetration at the interface of multi-wall carbon nanotube/amorphous carbon composites were studied via molecular dynamics simulations. In-situ strength of double-wall nanotubes bridging a matrix crack was calculated under various interfacial conditions. The structure of the nanotube reinforcement -ideal multi-wall vs. multi-wall with interwall sp³ bonding - influences the interfacial sliding and crack penetration. When the nanotube/matrix interface is strong, matrix crack penetrates the outermost layer of nanotubes but it deflects within the nanotubes with certain sp³ interwall bond density, resulting in inner wall pullout. With increasing the sp³ interwall bond density, the fracture mode becomes brittle; the fracture energy decrease while the bridging strength increases and then decreases. Our results suggest that the outermost nanotube wall can serve as a sacrificial layer such that the interface may be designed by effectively putting it inside the nanotubes. Controlling the density of sp³ interwall bond within the multiwall carbon nanotube makes the transition from brittle to tough failure modes in the composites even when the matrix/nanotube interface is strong.

---

Keywords

---