Metal Can Sit on Dandelions?

Boeing, one of the world’s leading airplane manufacturers, along with the help of HRL laboratories, University of California, and Caltech has developed the lightest metal structure on earth. It is called the “ultralight metallic microlattice” and it composed of 99.99% air. So far, this structure can be made of any material, but it is easiest made with nickel.  Remarkably, this new material is 100 times lighter than Styrofoam and it is so light it can sit atop a dandelion without crushing the delicate seeds!

The delicate seed heads of the dandelion.

Delicate seeds of the dandelion. Credit: Greg Hume

How can this material be so light? It is all related to the structure of it. The architecture of the ultralight metallic microlattice is created by hollow-tubed microlattices that are arranged to resemble the honeycomb structure of the human bone. Is human bone not dense and rigid? The outer casing of bone (compact bone) may be dense and rigid; however, inside the bone (spongy bone) is mostly hollow with an open cellular structure, much like a kitchen sponge, which allows it to be airy and lightweight.

The cross-section of a bone. Notice the special structure of the spongy bone.

The cross-section of a bone. Notice the special structure of the spongy bone.

To create this product, researchers created thin, hollow struts with a diameter of only 100 to 500 micrometers and a wall thickness of only 100 to 500 nanometers to mimic the architecture of the spongy bone. To give a comparison, this wall would be 1,000 times thinner than a human hair.

As well as being lightweight, this material is also one of the strongest in the world. It can be designed to maximize energy absorption which makes it a useful insulator. As an insulator, it can dampen shock, vibrations, and acoustic energy and therefore this material can be widely used across many fields of technology. Furthermore, this material is able to completely recover from a compression of over 50% strain.

With this discovery, Boeing has been investigating possible ways to implement  this material in planes. This would create lighter airplanes which would create more fuel efficient flights. Boeing has created and sold many Boeing 787, Dreamliners, which already consume substantially less fuel and with this new material, optimistically there is a possibility that Boeing will soon be creating the world’s most fuel efficient flights!

Here’s a video from Boeing which summarizes the “world’s lightest material”:

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Lightest Metal Ever
Credit: Boeing

– Maureen Lai

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