Iron and Nickel Cellular Structures by Sintering of 3D-Printed Oxide or Metallic Particle Inks

Inks comprised of metallic Fe or Ni powders, an elastomeric binder, and graded volatility solvents are 3D-printed via syringe extrusion and sintered to form metallic cellular structures. Similar structures are created from Fe2O3 and NiO particle-based inks, with an additional hydrogen reduction step before sintering. All sintered structures exhibit 92–98% relative density within their struts, with neither cracking nor visible warping despite extensive volumetric shrinkage ( 70–80%) associated with reduction (for oxide powders) and sintering (for both metal and oxide powders). The cellular architectures, with overall relative densities of 32–49%, exhibit low stiffness (1–6GPa, due to the particular architecture used), high strength (4–31MPa), and high ductility, leading to excellent elastic and plastic energy absorption, when subjected to uniaxial compression.