High Absorptivity Nanotextured Powders for Metal 3D Printing

The widespread of application of metal additive manufacturing (AM) is limited by the ability to control the complex interactions between the energy source and the feedstock material. Here we develop a process to introduce nanoscale grooves to the surface of copper powders which increases the powder absorptivity by up to 70% during laser powder bed fusion. The absorptivity increase enables printing of pure copper structures with densities up to 92% using laser energy densities as low as 82 J/mm³. Simulations show the enhanced powder absorptivity results from plasmonic resonances at nanoscale grooves features combined with multiple scattering events. The approach taken here demonstrates a generalized method to modifying the absorptivity and printability at low energy densities of reflective metal powders by changing the surface morphology and leveraging electric field localization in these self-evolving nanostructures.