Influence of heat treatment on the mechanical performance of Ti21S octet truss lattice structure fabricated by laser powder bed fusion

Abstract

Additive manufacturing allows the production of complex and custom designs including lattice structures—porous metallic structures with designed porosity and tailored mechanical properties. The bulk material has a key influence on the eventual properties of the porous lattice structure material. Among metallic biomaterials, beta-titanium alloys are gaining increasing interested because of their low Young’s modulus. In this work, the heat treatment of beta-Ti21S alloy is investigated in the context of octet truss lattice structures. The intention is to improve the performance of these structures for their reliable use in biomedical applications such as for bone implants. The study makes use of laser powder bed fusion of representative samples, uses microCT for physical characterization of manufacturing quality, while quasi-static and fatigue testing is performed to evaluate the performance of these lattice structures. The results indicate that the heat treatment significantly improves the fatigue properties of the lattice structures while changing the quasi-static failure mode more towards a stretch-based failure mode. These findings have practical implications for the implementation of this material and structure combination in medical implants. By enhancing the performance of the lattice structures, the study paves the way for their reliable use in biomedical applications.