Manufacturability of lattice structures fabricated by laser powder bed fusion: a novel biomedical application of the beta Ti-21S alloy

Additively manufactured lattice structures of titanium alloys, especially Ti6Al4V, are widely studied for their use in bone replacement implants. The porous nature of these lattice structures reduces the effective elastic modulus and hence can be matched to that of bone, in order to reduce stress shielding effects and allow long-term bone in- growth. The typical Ti6Al4V material manufactured by laser powder bed fusion requires post-process heat treatment to remove residual stresses and improve the ductility. A recently developed novel β-Ti alloy for laser powder bed fusion is of interest in this application due to its lower bulk elastic modulus, closer to that of bone compared to bulk Ti6Al4V. This implies that lattice structures need less porosity, improving the structural integrity while still matching the bone elastic modulus. The bulk β-Ti alloy also has high ductility without any post-process heat treatment, improving fatigue performance and reducing the number of steps involved in the process. In this work, the manufacturability of lattice structures in this new β-Ti alloy is investigated. The focus in this work is on coupon lattice samples with simple geometries and their mechanical and physical character- ization, allowing an assessment of manufacturability for future lattice implants of this β-Ti alloy.