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This new material redefines the limits of lightweight materials because of its unique “micro-lattice” cellular architecture. Using an innovative fabrication process developed by HRL senior scientist Dr. Alan Jacobsen, the team was able to make a material that consists of 99.99% open volume by designing the 0.01% solid at the nanometer, micron and millimeter scales. “The trick is to fabricate a lattice of interconnected hollow tubes with a wall thickness of 100 nanometers, 1,000 times thinner than a human hair,” said lead author Dr. Tobias Schaedler.
In addition to its ultra-low density, the material’s cellular architecture gives rise to unprecedented mechanical behavior for a metal, including complete recovery from compression exceeding 50% strain and extraordinarily high energy absorption. Developed for the Defense Advanced Research Projects Agency (DARPA), the novel material could be used for battery electrodes, catalyst supports, and acoustic, vibration or shock energy damping.
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.”
Design, processing, and cellular architecture of ultralight microlattices. (A) Polymer microlattice templates are fabricated from a three-dimensional array of self-propagating photopolymer waveguides. (B) The open-cellular templates are electroless plated with a conformal Ni-P thin film followed by etch removal of the template. (C) Image of the lightest Ni-P microlattice fabricated with this approach: 0.9 mg/cm3. (D and E) Images of two as-fabricated microlattices along with a breakdown of the relevant architectural elements.