Anisotropy of gyroid and stochastic lattice structures under axial loading

Lattice structures are an interesting possibility to tailor the strength-weight ratio and elasticity of metallic structures. In this study, Ti6Al4V gyroid and stochastic lattice structures with relative densities from 0.1 to 0.5 were manufactured by laser powder bed fusion technology, and the created structures were tested both under monotonic tension and compression to determine the strength properties and Young’s modulus. The study showed clear differences in anisotropy between the gyroid and stochastic lattice structures. In general, the anisotropy in the yield strength (YS) was higher in stochastic lattices, but the ratio between compression and tensile YS remained at 1.25 for all the studied densities. Higher variation was seen with gyroid lattices showing a ratio from 1.00–1.23 depending on the density. Gyroid structures were also stronger in strength, and superior strength levels were observed in comparison to the values found in the literature. The anisotropy in Young’s modulus (E) was high and significant differences were observed with different densities, but the trend between the gyroid and stochastic structures was similar. Interestingly, the ratio between compression and tensile Young’s modulus decreased by increasing the density, being close to 0.5 at 0.44 g/cm3 and 0.15 at 2.2 g/cm3. The measured E values were low, making them an especially promising solution for medical bone replacements.