Sinter‐Based Additive Manufacturing of Graded Porous Titanium Scaffolds by Multi‐Inks 3D Extrusion

A 3D printing approach to design and produce cellular scaffolds with a precise tunable pore architecture, in terms of size, fraction, and interconnectivity is reported. Different metallic inks are formulated by mixing hydrogel with Ti–6Al–4V atomized powders of various sizes. After 3D printing by direct‐ink writing (DIW) followed by debinding and sintering, the fraction and size of macropores (, designed by computer‐aided design (CAD)) and micropores (, remaining after sintering), the roughness and the microstructure are determined by high‐resolution X‐ray tomography and electron microscopy, and correlated to the initial powder size. It is shown that playing with initial powder size allows designing different pore architectures, from interconnected micropores to fully dense filaments. These phenomena are combined with a multi‐inks DIW approach to fabricate architectured structures with graded microporosity. This new route is promising for the production of functional materials, such as biomedical scaffolds or implants, with tunable osseointegration, stiffness, and strength. The micropores could also be loaded with active molecules and positioned according to release needs.