“The novel lightweight construction materials resemble the framework structure of a half-timbered house with horizontal, vertical, and diagonal struts,” says Jens Bauer, Karlsruhe Institute of Technology (KIT). “Our beams, however, are only 10 µm in size.” In total, the lightweight construction elements are about 50 µm long, wide, and high.
“Nature also uses open-pore, non-massive structures for carrying loads,” Oliver Kraft, KIT, explains. Examples are wood and bones. At the same density, however, the novel material produced in the laboratory can carry a much higher load. A very high stability was reached by a shell structure similar to the structure of honeycombs. It failed at a pressure of 28 kg/mm2 only and had a density of 810 kg/m3. This exceeds the stability / density ratio of bones, massive steel, or aluminum. The shell structure produced resembles a honeycomb with slightly curved walls to prevent buckling.
To produce the lightweight construction materials, 3D laser lithography was applied. Laser beams harden the desired microstructure in a photoresist. Then, this structure is coated with a ceramic material by gas deposition. The structures produced were subjected to compression via a die to test their stability.
Microstructured materials are often used for insulation or as shock absorbers. Open-pore materials may be applied as filters in chemical industry.
High-strength cellular ceramic composites with 3D microarchitecture, Jens Bauer, Stefan Hengsbach, Iwiza Tesari, Ruth Schwaiger, and Oliver Kraft, PNAS Early Edition, DOI: 10.1073/pnas.1315147111
Karlsruhe Institute of Technology (KIT) is a public corporation pursuing the tasks of a state university of Baden-Wuerttemberg and of a national research center of the Helmholtz Association. The KIT mission combines the three strategic lines of activity of research, higher education, and innovation. With about 9,400 employees and 24,500 students, KIT is one of the big institutions of research and higher education in natural sciences and engineering in Europe.