Innovative design and compression performance of selective laser melting-printed tantalum artificial vertebral bodies

Abstract

Tantalum (Ta) holds considerable potential for clinical applications in artificial vertebral bodies (AVBs) owing to its excellent biocompatibility. A novel Ta AVB structure was engineered by combining thin-walled structure topology optimization with lattice structure filling design methods. Three types of Ta AVBs—designated as AVB-1, AVB-2, and AVB-3—were fabricated using selective laser melting. The influence of sidewall curvature on the mechanical properties and deformation behavior of AVBs was investigated through compression tests and finite element analysis. The elastic modulus and yield strength of the Ta lattice structures ranged from 1.75 to 3.21 GPa and 31 to 65 MPa, respectively. Incorporating topologically thin walls enhanced the elastic modulus and yield strength by factors of 2.26-3.77 and 3-3.62, respectively. A decrease in sidewall curvature was associated with an increase in both elastic modulus and yield strength of the AVBs. Specifically, as the sidewall curvature decreased from 0.027 to 0 mm−1, the elastic modulus and yield strength increased by factors of 2.76 and 2.19, respectively. The yield strengths of the AVBs were comparable to those of human cortical bone. Among the three designs, AVB-2 exhibited the highest yield-strength-to-elastic-modulus ratio (0.029), compared to AVB-1 and AVB-3 (0.024 and 0.019, respectively), suggesting that the optimal sidewall curvature is 0.014 mm−1. AVB-2 effectively mitigated the stress shielding effect while maximizing the load-bearing capacity, indicating its significant potential for clinical applications.

Keywords

Tantalum / Selective laser melting / Artificial vertebral body / Lattice structure / Topology optimization