Additive Manufacturing of Micro-Architected Metals via Hydrogel Infusion

Metal additive manufacturing (AM) has emerged as a uniquely powerful tool to produce complex and high-performance parts with applications from the aerospace to biomedical fields. Most existing metal AM techniques use heat to define part shape via thermally initiated melting or sintering. In contrast, we report an AM technique, coined hydrogel infusion additive manufacturing (HIAM), that produces metals and alloys with microscale resolution via vat photopolymerization (VP). To fabricate micro-architected metal structures, we infuse 3D-architected hydrogels with aqueous metal precursors, then calcine and reduce the infused hydrogel scaffolds to create miniaturized metal replicas. Unlike existing VP strategies, which incorporate target materials or precursors into the photoresin during printing, HIAM does not require re-optimization of resins and curing parameters for different materials, enabling quick iteration, compositional tuning, and the ability to fabricate multimaterials. We demonstrate HIAM of micro-architected metals such as copper, nickel, silver, cobalt, cupronickel alloys, high entropy alloys, and tungsten with critical dimensions of ~50 µm. Hydrogel scaffolds can be considered responsive architected materials—we demonstrate how a single architected gel can respond to a variety of chemical and thermal stimuli to transform into a vast array of metals, providing a pathway to create advanced micro-architected metals.