Microstructural features and compressive properties of SLM Ti6Al4V lattice structures

Lightweight lattice structures have great potentials for the application in medical industries due to their large specific surface area and high strength-to-weight ratio. Selective laser melting (SLM) as one of the most attractive additive manufacturing processes has been widely used for the fabrication of porous structures. In this study, two Ti6Al4V lattice structures, trabecular (Trab.) and triply periodic minimal surface (TPMS), were produced through SLM to study the microstructural distribution and compressive properties with different cell types. The results show that cell type has insignificant effect on the microstructure of the SLM lattice structures studied in this work. For both lattice samples, refined near-equiaxed beta phase was formed in the lattice struts, while coarse beta phase was formed in the solid bulk region. However, cell type posed significant effects on the compressive properties of the lattice structures. The Trab. structure was found to have higher compressive strength and better energy absorption capacity than the TPMS structure. This work demonstrated that the elastic modulus of Trab. (5.58 GPa) and TPMS (5.51 GPa) lattices could be comparable to that of natural bones (0.022-21 GPa) through rational structural parameters design, which can avoid the stress shielding effect that always occurs on biomedical implant.