Geometric and Mechanical Properties of Ti6Al4V Skeletal Gyroid Structures Produced by Laser Powder Bed Fusion for Biomedical Implants

Skeletal gyroid structures possess promising applications in biomedical implants, owing to their smooth and continuously curved surfaces, open porosity, and customisable mechanical properties. This study simulated the geometric properties of Ti6Al4V skeletal gyroid structures, with relative densities ranging from 1.83% to 98.17%. The deformation behaviour of these structures was investigated through a combination of uniaxial compression tests and simulations, within a relative density range of 13.33% to 50% (simulation) and 15.19% to 41.69% (experimental tests). The results established explicit analytical correlations of pore size and strut diameter with the definition parameters of the structures, enabling precise control of these dimensions. Moreover, normalised Young’s modulus (ranging from 1.05% to 20.77% in simulations and 1.65% to 15.53% in tests) and normalised yield stress (ranging from 1.75% to 17.39% in simulations and 2.09% to 13.95% in tests) were found to be power correlated with relative density. These correlations facilitate the design of gyroid structures with low stiffness to mitigate the stress-shielding effect. The presence of macroscopic 45° fractures in the gyroid structures confirmed that the primary failure mechanism is induced by shear loads. The observed progressive failure and plateau region proved the bending-dominant behaviour and highlighted their excellent deformability. Additionally, the anisotropy of gyroid structures was confirmed through variations in stress and strain concentrations, deformation behaviour, and Young’s modulus under different loading directions.