Failure mechanism and property improvement of carbon-nanotube fibers

L. Zheng
Nanyang Technological University, SG

Keywords: CNT fiber, failure mechanism, strain rate


Carbon-nanotube (CNT) fibers have already demonstrated the potentials of retaining the intrinsic properties of individual CNTs at a practical scale level. But current reports in this area show large variations and inconsistence in fiber’s properties, and further improvements is hindered by the less understanding of fiber’s failure mechanism. In this work, we study CNT fiber’s failure mechanism from the strain-rate dependences of CNT fibers’ mechanical behaviors, and find that the mechanical responses of CNT fibers to the strain rate fall into two different regimes. Further studies indicate that two different failure mechanisms associate with these two regimes: tube sliding at low strain-rate regime, and “cascade-like” breaking at high strain-rate regime. This implies that the fiber’s reliability is limited by the tube sliding, but its performance is determined by the tube alignment, and future improvement must deal with both of them at the same time. The significances of this work include: 1) This is the first systematic study on CNT fiber’s failure mechanism; 2) The finding of the strain-rate dependences of fiber’s properties can explain the variation/inconsistence of existing results; 3) Two failure mechanisms can clearly indicate the direction of future improvement.