Tuesday, April 18, 2006

Symmetry-, Time-, and Temperature-Dependent Strength of Carbon Nanotubes

by Traian Dumitrica, Ming Hua, & Boris I. Yakobson Proceedings of the National Academy of Sciences, 18 Apr 2006 Although the strength of carbon nanotubes has been of great interest, their ideal value has remained elusive both experimentally and theoretically. Here, we present a comprehensive analysis of underlying atomic mechanisms and evaluate the yield strain for arbitrary nanotubes at realistic conditions. For this purpose, we combine detailed quantum mechanical computations of failure nucleation and transition-state barriers with the probabilistic approach of the rate theory. The numerical results are then summarized in a concise set of equations for the breaking strain. We reveal a competition between two alternative routes of brittle bond breaking and plastic relaxation, determine the domains of their dominance, and map the nanotube strength as a function of chiral symmetry, tensile test time, and temperature. Read more