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

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Understanding the microstructural evolution of metallic materials is essential if mechanical properties are to be tailored to meet the needs of specific applications. The present study investigates four multi-component alloys based on the biocompatible elements Ta, Nb, and Ti, which were designed via thermodynamic calculations, synthesized by arc-melting and subjected to homogenization heat treatments. The microstructures of the alloys were characterized using SEM and XRD, whilst the mechanical properties were evaluated through hardness testing, room-temperature compression, and 3-point bending on microsamples. Results show a strong correlation between the mechanical performance and the Ti content, homogenization time and temperature. The overall hardness of all alloys increased after heat treatment, though no clear relationship with grain orientation could be established. The compression tests revealed high plastic deformability (> 25%) and composition-dependent yield strength for all alloys tested, with deviations noted at higher Ti contents post-homogenization. All alloys demonstrated enhanced elastic deformability and reduced flexural moduli compared to the reference alloy thus aligning more closely with bone and suggesting improved suitability for orthopaedic applications. Notably, the equimolar Ta-Nb-Ti alloy exhibited the most balanced mechanical properties in terms of hardness, flexural strength and compressive properties, making it a promising candidate for orthopaedic applications. As we previously reported on the excellent biocompatibility of similar alloys, this study now provides further insights into the potential of tailoring the systems for specific and application related mechanical properties.