3D Printing of Hierarchically Structured Metals/Alloys Based on Ion‐Infused Porous Hydrogels

Abstract Hierarchically porous‐structured metals show tremendous potential for mechanical applications in the aerospace, automotive, and healthcare sectors. Accurately controlling both the microstructural pore morphology and the macroscopic geometric shape presents a significant challenge and directly impacts its applications. Existing approaches involve combining 3D printing with sacrificial templating, where the introduction of templating agents restricts the control of the 3D printing process. Here, a template‐free process is developed for the manufacturing of hierarchical metallic structures from DLP 3D‐printed ion‐infused porous hydrogels. The porous structure of the hydrogel scaffold introduced by lyophilization not only induces the formation of microporous metallic structures during the sintering process but also helps reduce the internal stresses within the material to facilitate shape integrity. Hierarchically structured iron and iron‐based high‐entropy alloys with pore diameters ranging from sub‐micrometer to millimeter are fabricated to demonstrate the feasibility of this method. This work is anticipated to inspire the design and fabrication of high‐performance metallic structures for functional applications such as catalysts or metamaterials.