New lightweight, flexible metallic materials

Lawrence Livermore National Laboratory (LLNL) engineers have recently achieved unprecedented scalability in 3D-printed architectures of arbitrary geometry, opening the door to super-strong, ultra-lightweight and flexible metallic materials for aerospace, the military and the automotive industry.

In a study published online in Nature Materials, LLNL engineers report building multiple layers of fractal-like lattices with features ranging from the nanometer to centimeter scale, resulting in a nickel-plated metamaterial with a high elasticity not found in any previously built metal foams or lattices.

The lattices were initially printed out of polymer, using a one-of-a-kind Large Area Projection Micro-Stereolithography (LAPuSL) printer invented by LLNL engineer Bryan Moran, who won an R&D 100 award for the design. The lattice structure was then coated with a nickel-phosphorus alloy and put through post-processing to remove the polymer core, leaving extremely lightweight, hollow tube structures. While testing the nickel-plated material, researchers found that structures fashioned with walls 700 nanometers thick broke under a 5 percent strain, while those with 60-nanometer walls stretched about 20 percent before failing.

Besides flexibility, researchers said the concept could overcome the current limitations of 3D-printed micro and nano-architectures by addressing the usual tradeoff between high resolution and build size and extend to a variety of large-scale applications, including aircraft parts, batteries or stretchable armor for the military.