Effect of build and unit cell orientation on the tensile, compressive, and torsional behavior of Ti-6Al-4V gyroid sheet-based structures

Laser powder bed fusion (LPBF) enables the fabrication of intricate porous metallic structures, such as the sheet-based gyroid, recently used in orthopedic implants. Many implants are subjected to a complex stress environment, making strength verification across different loading modes imperative. This study investigates the effect of both unit cell and build orientation on gyroid structures. Build orientation and unit cell orientation were varied from 0 degrees to 90 degrees in 15 degrees increments to determine the degree of anisotropy of Ti-6Al-4V samples in tension, compression, and torsion. For the relatively isotropic gyroid structure, build orientation was the most influential factor on anisotropy in tension and compression. The samples with 30 degrees build orientation (B30) showed the highest strength across all three loading modes due to the overall print quality and orientation of layers withstanding the applied forces. These results guide the design optimization of 3D printed orthopedic implants with varying build and unit cell orientation.