On the Mechanical Behavior of WS2 Nanotubes under Axial Tension and Compression

by Ifat Kaplan-Ashiri et al. Proceedings of the National Academy of Sciences, 17 Jan 2006 The mechanical properties of materials and particularly the strength are greatly affected by the presence of defects; therefore, the theoretical strength is not generally achievable for macroscopic objects. On the contrary, nanotubes, which are almost defect-free, should achieve the theoretical strength that would be reflected in superior mechanical properties. In this study, both tensile tests and buckling experiments of individual WS₂ nanotubes were carried out in a high-resolution scanning electron microscope. Tensile tests of MoS₂ nanotubes were simulated by means of a density-functional tight-binding-based molecular dynamics scheme as well. The combination of these studies provides a microscopic picture of the nature of the fracture process, giving insight to the strength and flexibility of the WS₂ nanotubes. Fracture analysis with recently proposed models indicates that the strength of such nanotubes is governed by a small number of defects. A fraction of the nanotubes attained the theoretical strength indicating absence of defects. Read more