Effect of stress state on the mechanical behavior of 3D printed porous Ti6Al4V scaffolds produced by laser powder bed fusion

• Tensile, compressive, shear, and torsional loads applied to lattice structures. • Gyroid is stiffer and stronger than strut-based lattices in stress states studied. • Universal sample geometry is required to compare behavior across stress states. Metallic lattice structures have interconnected porosity for promoting osseointegration and stiffness comparable to bone ideal for minimizing stress shielding. These benefits have caused a widespread proliferation of porous metal scaffolds in orthopedic implants. Once implanted, these devices experience complex stress states under physiological loading. To design these structures to mimic the mechanical behavior of bone, their performance under these conditions must be understood. This study explores the effects of stress state on the mechanical behavior of three lattice structures across a range of clinically relevant porosities. The scaffolds were fabricated via 3D printing Ti6Al4V using LBPF. The gyroid exhibited more efficient mechanical performance at equivalent porosity than the other structures for all loading modes. Stress state has a statistically significant impact on the strength of the scaffolds. This study provides the first dataset on the impact of stress state on the fracture of 3D printed biomimetic scaffolds for orthopedic applications.