King, alumnus Pikul, colleagues develop “metallic wood”
In a paper published in the journal Nature Scientific Reports, a team from the University of Pennsylvania and the University of Illinois in the U.S. and the University of Cambridge in the UK describe building a sheet of nickel with nanoscale pores that make it as strong as titanium but four to five times lighter again. Shortly after publication, the breakthrough news was on the homepage of the U.S. Department of Energy.
The empty space of the pores, and the self-assembly process in which they're made, make the porous metal akin to a natural material, such as wood.
And just as the porosity of wood grain serves the biological function of transporting energy, the empty space in this "metallic wood" could be infused with other materials, the researchers say. Infusing the scaffolding with anode and cathode materials, for example, would allow it to be used for a plane wing or prosthetic leg that's also a battery.
"The reason we call it metallic wood is not just its density, which is about that of wood, but its cellular nature," says Pennsylvania's James Pikul, who led the research. Pikul is a three-time alumnus of MechSE (BSME ’09, MSME ’11, PhDME ’15), and was a graduate researcher in Professor Bill King’s group. King is co-author on the paper, along with MatSE professors Paul Braun and Runyu Zhang.
Image above: A microscopic sample of the "metallic wood.” Its porous structure is responsible for its high strength-to-weight ratio, and makes it more akin to natural materials, like wood. Credit University of Pennsylvania.