Biomechanical influence of structural variation strategies on functionally graded scaffolds constructed with triply periodic minimal surface

The rapid development of additive manufacturing technology makes it possible to fabricate parts with complex inner structures, especially for functionally graded scaffolds (FGS) in the field of bone tissue engineering. The parametric design of FGS is of great significance to the in-depth study of the effects of structural parameters of porous bone scaffolds on their mechanical properties and rehabilitation of patients. The present study proposed a parametric design method for FGS using a triply periodic minimal surface (TPMS). Graded structures were obtained by altering the Gyroid TPMS equation. Uniform and functionally graded samples were fabricated using selective laser melting of Ti-6Al-4V powder. The FGSs successfully realized flexible control of structural parameters and showed comparable mechanical properties and permeability with natural bone tissue. Furthermore, heat treatment was verified to be an effective way to improve the ductility of TPMS-FGS. The deformation process and principal strain distribution of the FGSs were elucidated using a digital image correlation method. The FGSs proposed in the present study showed great potential in orthopedic implant or bone-substituting biomaterials.