Department of Physics, Engineering Physics & Astronomy

Queen's University
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Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

Unveiling the Mechanics of Nanostructures

Tobin Filleter
University of Toronto

Friday, March 15, 2013
1:30 PM @ Stirling A

Abstract:

Nanostructures are emerging as building blocks of advanced materials, next generation electronics, and electromechanical devices. For mechanical and electromechanical applications, such as carbon fibers and flexible electronic interconnects, this is driven by the exceptional mechanical properties of nanostructures and novel nanoscale mechanical phenomena. To unveil such properties and phenomena we utilize in situ electron microscopy mechanical testing methods which can probe deformation and failure of structures with high spatial resolution while simultaneously measuring mechanical properties such as strength, stiffness, and toughness. In this presentation I will provide an overview of in situ scanning electron microscopy (SEM) and transmission electron microscopy (TEM) mechanical testing methods with a focus on two material systems: 1) penta-twinned silver nanowires and 2) double-walled carbon nanotube fibers. In situ TEM experiments of silver nanowires, coupled with molecular dynamics simulations (MD), have revealed a unique strain hardening mechanism exhibited by twinned silver nanowires which is accompanied by a combination of high strength and high ductility making them promising candidates for use in flexible electronics. In situ SEM and TEM experiments conducted on double-walled carbon nanotube fibers have been compared to atomistic and course-grained simulations to reveal the nature of shear interactions at multiple scales within the fibers in order to guide the design of strong and tough macroscopic carbon fibers.