Modeling of superelastic implant structures made of biomedical oxygen-added Ti-25Nb based shape memory alloys

This work studies the thermomechanical behavior of Ti-25Nb, Ti-25Nb-0.3O and Ti-25Nb-0.7O shape memory alloys (SMAs), for potential biomedical applications. A constitutive model derived from Brinson's model was developed to simulate the superelastic response. A numerical model of biomedical implant support was also developed using Abaqus and compared with experimental data. Results indicate that oxygen addition enhances phase stability, superelastic recovery, and stress distribution uniformity, with Ti-25Nb-0.3O exhibiting lower peak stresses and more homogeneous deformation. The support implant is composed of a lattice (X-type, honeycomb-type) structure with varying ligament thicknesses evaluated, demonstrating that ligament size strongly affects mechanical response and porosity, with thinner ligaments maintaining desirable superelastic characteristics. The combination of Ti-25Nb-0.3O alloy and optimized lattice geometry is a promising alternative to conventional Ti-6Al-4V alloy for implantable support structures, providing improved mechanical compatibility and elastic behavior. Future work should focus on fatigue resistance, manufacturability, and biocompatibility under physiological conditions to advance clinical relevance.