"Metalic microlattice" lightest structural Material in world

Researchers in the US have broken the world record for the lightest structural material. The metal-based microlattice structures are significantly less dense than the rarest aerogels and other ultralight foams, while exhibiting high strength and an unexpectedly high ability to absorb energy and recover shape after compression. The materials could find use in a range of applications, from aircraft structural components to acoustic damping and shock absorption.

A metallic microlattice is a synthetic porous metallic material, consisting of an ultra-light form of metal foam, which has a density as low as 0.9 mg/cm3.  It was developed by a team of scientists from HRL Laboratories,led by "Tobias Schaedler",in collaboration with researchers at University of California, Irvine and Caltech, and was first announced in November 2011. The prototype samples were made from a nickel-phosphorus alloy.

To create the structure, a polymer template is first produced by placing a mask patterned with circular holes over a reservoir of a photosensitive thiol-ene monomer. UV light is shone on the mask and where the light meets the monomer it polymerises it. 'As the light begins to polymerise the liquid monomer, the change in refractive index between the polymer and monomer begins to tunnel the light, just as in a fibre optic,' says Schaedler. 'This leads to the formation of a self-propagating photopolymer waveguide, or fibre, within the monomer reservoir. We form these waveguides in multiple directions and intersect them together to create an interconnected network. Then we clean out the uncured liquid monomer with a solvent, and the result is a micro-lattice structure, where the self-propagating waveguides are the individual structural lattice members.

researchers at HRL Laboratories have developed this  , consisting of "micro-lattice cellular architecture" that is 99.99% air. Though technically a metal comprised of nanotubes, the material has surprising elasticity—"including complete recovery from compression exceeding 50%".

Dr. Bill Carter, manager of the Architected Materials Group at HRL, lays out the vision for these micro-lattice materials by drawing parallels to large structures: "Modern buildings, exemplified by the Eiffel Tower or the Golden Gate Bridge, are incredibly light and weight-efficient by virtue of their architectures. We are revolutionizing lightweight materials by bringing this concept to the materials level and designing their architectures at the nano and micro scales."