Effects of Unit Cell Topology on the Mechanical Properties of Porous Tantalum Structures via Laser Powder Bed Fusion

Additive manufacturing (AM) of porous tantalum scaffolds receives extensive attention because the demands for tantalum implants grow rapidly. Understanding the effects of unit cell topology on the mechanical properties of porous tantalum scaffold structures is critical for durable implant design, but it is still lacking. Herein, porous tantalum structures with two types of unit cells (body-centered cubic [BCC] and body-centered cubic deformation [BCC-D]) are additively manufactured with laser powder bed fusion (LPBF). The geometric characteristics and mechanical properties of the manufactured structures are comparatively studied. It is found that the mechanical properties of BCC porous tantalum in the building and horizontal directions are discovered to be nearly identical, with elastic modulus and yield strength of nearly 1.9 GPa and 56 MPa, respectively. Unit cell topology dominates the mechanical anisotropy and compressive failure mode of porous tantalum. The mechanical properties of the BCC-D topology are anisotropic, and the fracture morphology indicates that it is a cleavage fracture and a minor ductile fracture. The capacity to finely control the mechanical properties of porous tantalum structure through unit cell topology is prominent for optimizing implant structure for personalized medical care.