We love our 3D printers. But sometimes we really wish we could print in metal. While metal printing is still out of reach for most of us, HRL Labs announced a powdered aluminum printing process that they claim is a breakthrough because it allows printing (and welding) of high-strength aluminum alloys that previously were unprintable and unweldable.
The key is treating the metal with special zirconium-based nanoparticles. The nanoparticles act as nucleation sites that allow the aluminum to form the correct microstructure. The full paper on the process appears in Nature.