Fabrication and deformation of three-dimensional hollow ceramic nanostructures
Dongchan
Jang, Lucas R. Meza, Frank Greer, Julia R. Greer
Nature Materials, 12 (2013) 893–898, DOI:doi:10.1038/nmat3738

Left: Skeletal natural biological materials versus TiN nanolattices. Right: Compression experiments on a single unit cell.

In the analysis of complex, hierarchical structural meta-materials, it
is critical to understand the mechanical behavior at each level of hierarchy in
order to understand the bulk material response. We report the fabrication and
mechanical deformation of hierarchical hollow tube lattice structures with
features ranging from 10 nm to 100 μm,
hereby referred to as nanolattices. Titanium nitride (TiN) nanolattices were
fabricated using a combination of two-photon lithography, direct laser writing,
and atomic layer deposition. The structure was composed of a series of
tessellated regular octahedra attached at their vertices. In situ uniaxial
compression experiments performed in combination with finite element analysis
on individual unit cells revealed that the TiN was able to withstand tensile
stresses of 1.75 GPa under monotonic loading and of up to 1.7 GPa under cyclic
loading without failure. During the compression of the unit cell, the beams
bifurcated via lateral-torsional buckling, which gave rise to a hyperelastic
behavior in the load–displacement
data. During the compression of the full nanolattice, the structure collapsed
catastrophically at a high strength and modulus that agreed well with classical
cellular solid scaling laws given the low relative density of 1.36 %. We
discuss the compressive behavior and mechanical analysis of the unit cell of
these hollow TiN nanolattices in the context of finite element analysis in
combination with classical buckling laws, and the behavior of the full
structure in the context of classical scaling laws of cellular solids coupled
with enhanced nanoscale material properties.


Screendump from the video below, showing the fabrication method of the 3D architected nano meta materials described in the Nature publication above.//www.youtube.com/embed/Dahz8wYWvos

Video from Solve for X – Julia Greer – 3D Architechted Nano Metamaterials at World Economic Forum.

The Julia Greer Group at Caltech: http://www.jrgreer.caltech.edu/home.php

Idea and inspiration for this post taken from the Next Big Future Blog.