seed projects

Nathan Mara, David Poerschke, Lee Penn, and Andreas Stein: Thermomechanically Robust Nanocomposites via Scalable Mesoporous Templating:

Metal-ceramic nanocomposites exhibit exceptional mechanical properties with combinations of high strength, toughness, and hardness not achievable in monolithic metals or ceramics. These properties arise due to the increased role that interfaces play in dislocation generation and transmission as the characteristic length scale of the composite is reduced. This project is developing scalable processing routes to produce periodic 3D structures and will employ nanomechanical characterization techniques to elucidate the deformation processes in these hierarchical nanocomposites. The composites will be synthesized by colloidal templating of three-dimensionally ordered mesoporous (3DOm) or macroporous (3DOM) tungsten, nanocasting of Si-based preceramic polymers, and thermal conversion to SiC and Si₃N₄. Based on knowledge of the phase equilibria in these systems, it is anticipated that the W-Si₃N₄ composites will feature direct W-Si₃N₄ interfaces while interfacial silicide or carbide formation in W-SiC composites will influence the mechanical coupling between the metal and ceramic phases. The effort seeks to understand the relationships between this interphase structure and overall composite length scale (e.g., W-ligament) on the temperature-dependent mechanical response in order to develop strong, hard, and tough 3-D metal-ceramic nanocomposites.

Funded by the National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-1420013