Exploring the potential of Ta-Nb-Ti-based multi-component alloys for biomedical applications: Microstructural evolution and key mechanical observations

The present study investigates multi-component alloys based on the biocompatible elements Ta, Nb, and Ti, designed via thermodynamic calculations, synthesized by arc-melting, and subjected to homogenization heat treatments. Microstructures were characterized using SEM and XRD, whilst mechanical properties were evaluated through hardness testing, room-temperature compression, and 3-point bending on microsamples. Results show a strong correlation between mechanical performance and Ti content, homogenization time, and temperature. Overall hardness increased after homogenization, which is attributed to solid solution strengthening. However, grain-orientation specific hardness indentation did not yield clear correlations, attributed to the high number of active slip systems in bcc lattices and the large grain sizes present. Compression tests revealed high plastic deformability (> 25 %) and composition-dependent yield strength for all alloys, with deviations noted at higher Ti contents post-homogenization. All alloys demonstrated enhanced elastic deformability and reduced flexural moduli compared to the reference, aligning more closely with bone and suggesting improved suitability for orthopedic applications. Notably, the equimolar Ta-Nb-Ti alloy exhibited the most balanced mechanical properties in terms of hardness, flexural strength, and compressive behavior, making it a promising candidate for further evaluation as an orthopedic implant material.