Ph.D. Proposal Presentation by
Wednesday, May 18, 2005
(Dr. Min Zhou , Chair)
"Modeling and Simulation of the Mechanical Behavior of Single-Crystalline Metallic Nanowires"
The proposed research focuses on the characterization of the structure and mechanical behavior of single-crystalline metallic nanowires. Materials including Cu, Au, Pt, and Ag are chosen for the analysis. Classical molecular dynamics simulations with embedded-atom method potentials will be performed to study the mechanical response of the metallic nanowires during tensile loading and unloading. The first part of research will investigate the structural stability and lattice reconstruction in the top-down fabrication process. Of particular interest is the critical condition for the lattice reconstruction. The second part focuses on the characterization of a novel rubber-like pseudoelastic behavior and shape memory effect in the metallic nanowires. Emphasis is on the transformation mechanism, driving force, and quantification of the size and temperature effects. A lattice-based kinetics model will be developed by incorporating the atomistic simulation results. This model is expected to quantify the response time for the transformation, which is critical for the application of shape memory materials. A deformation mechanism-based constitutive model will be developed to predict the stress-strain response of metallic nanowires under quasi-static loading conditions. The final part of this research will investigate the size and rate effects on the plastic deformation mechanisms. A dislocation-based model will be developed to predict the critical condition for the amorphization in nanowires. This research is the first to reveal and characterize the novel rubber-like pseudoelastic behavior and shape memory effect in metallic nanowires. It is expected to yield tools and insights for the development of nanoscale components such as sensors, actuators, and transducers.