Additive manufacturing of metallic cellular materials via three-dimensional printing

Cellular materials, metallic bodies with gaseous voids interspersed throughout the solid body, are a promising class of materials that offer high strength accompanied by a relatively low mass. Recent research has focused in the topological design of cellular materials in order to satisfy multiple design objectives. Unfortunately, these design advances have not been met with similar advances in cellular material manufacturing as existing techniques constrain a designer to a predetermined part mesostructure, material type, and macrostructure. In an effort to address these limitations, the authors have developed a manufacturing process chain centered on an augmented three-dimensional printing process. Specifically, metallic cellular materials are made by selectively printing solvent into a bed of spray-dried metal oxide ceramic powder. The resulting green part is then sintered in a reducing atmosphere to chemically convert it to metal. The resultant process has produced maraging steel cellular artifacts featuring a 270-mu m wall thickness and angled trusses and channels that are less than 1 mm in diameter.