Jan-Oliver Sass (Rostock, DE), Marie-Luise Sellin (Rostock, DE), Elisa Kauertz (Rostock, DE), Jan Johannsen (Hamburg, DE), Dr. Markus Weinmann (Goslar, DE), Dr. Melanie Stenzel (Goslar, DE), Dr. Danny Vogel (Rostock, DE), PD Dr. Anika Jonitz-Heincke (Rostock, DE), Prof. Dr. Rainer Bader (Rostock, DE)
Abstract text (incl. figure legends and references)
Introduction
Laser beam powder bed fusion (PBF-LB) is an increasingly used additive manufacturing technology for the production of bone implants. Low modulus β-stabilized Ti alloys are being developed to reduce stress-shielding at the bone-implant interface1. These Ti alloys can be composed of bio-tolerant metals such as Nb and Ta2.
Objectives
This experimental study investigates the effect of the Nb content and the build orientation on the mechanical properties and biocompatibility of Ti-xNb-6Ta (x = 20, 27, 35) alloys processed by PBF-LB.
Materials and Methods
Ti/Nb/Ta spherical powders were obtained by electrode induction-melting gas atomization and used for PBF-LB.
Cylindrical specimens were additively manufactured and compressively loaded to analyze their mechanical properties as a function of Nb content and build orientation (0°, 45°, 90°). Functionality was assessed by the ratio of compressive modulus to yield strength.
Furthermore, human osteoblasts were cultured on cylindrical specimens fabricated at 0° or 90° build orientation. After cultivation for three days, mRNA levels of differentiation and inflammation markers were examined.
Results
Nb content and build orientation influenced the mechanical properties (Fig. 1) and cell behavior. The best mechanical functionality was observed for Ti-20Nb-6Ta in the 90° build orientation. Enhanced osteoblastic differentiation and reduced induction of inflammation were observed for Ti-20Nb-6Ta in the 0° build orientation.
Conclusion
Mechanical functionality and osteoblastic differentiation capacity were demonstrated for the investigated Ti-xNb-6Ta alloys. Ti-20Nb-6Ta showed the best results and is a promising material option for bone implants.
1 Farrahnoor A., et al. 2021. IJMR. 112 (6):505–513
2 Wei TY., et al. 2018. J Mech Behav Biomed Mater. 86 (10):224-231
Fig. 1: Elastic admissible strain of Ti-xNb-6Ta (x = 20, 27, 35) alloys manufactured by PBF-LB in different build orientations.