Hierarchical 3D nano-​architectures for biomimetics, batteries, and lightweight structural materials

Creation of extremely strong yet ultra-light materials can be achieved by capitalizing on the hierarchical design of 3-dimensional nano-architectures. Such structural metamaterials exhibit superior thermomech. properties at extremely low mass densities (lighter than aerogels), making these solid foams ideal for many scientific and technol. applications. The dominant deformation mechanisms in such "meta-materials", where individual constituent size (nanometers to microns) is comparable to the characteristic microstructural length scale of the constituent solid, are essentially unknown. To harness the lucrative properties of 3-dimensional hierarchical nanostructures, it is crit. to assess mech. properties at each relevant scale while capturing the overall structural complexity. We present the fabrication of 3-dimensional nano-lattices whose constituents vary in size from several nanometers to tens of microns to millimeters. We discuss the deformation and mech. properties of a range of nano-sized solids with different microstructures deformed in an in-situ nanomech. instrument. Attention is focused on the interplay between the internal crit. microstructural length scale of materials and their external limitations in revealing the phys. mechanisms which govern the mech. deformation, where competing material- and structureinduced size effects drive overall properties. We focus on the deformation and failure in metallic, ceramic, and glassy nano structures and discuss size effects in nanomaterials in the framework of mechanics and physics of defects. Specific discussion topics include: nano-mech. expts. on nano structures extd. from particular phases and contg. specific boundaries and interfaces, flaw sensitivity in fracture of nano structures, and the creation of hollow nano-lattices for applications in biomedical devices, ultra lightwt. Li-ion batteries, and damage-tolerant cellular solids