Four novel superelastic alloys, Ti-41Zr-12Nb, Ti-42Zr-11Nb, Ti-43Zr-10Nb, Ti-44Zr-10Nb (at.%), were obtained and studied in terms of their microstructure and mechanical properties. The obtained alloys were subjected to thermomechanical treatment, providing alloys with a pronounced superelastic behavior. Materials phase composition and microstructure were studied using XRD and SEM methods. Based on the XRD results, maximum lattice strains in the [011]β direction were calculated as 5.9%, 6.3%, 7.5%, and 7.2% for Ti-41Zr-12Nb, Ti-42Zr-11Nb, Ti-43Zr-10Nb, and Ti-44Zr-10Nb alloys, respectively. Mechanical properties of the thermomechanically-treated alloys were studied by Vickers microhardness testing, static tensile testing, and superelastic mechanical cycling. The maximum superelastic recovery strains attained at room temperature was 3.7%, 1.9%, 3.2%, and 3.0% for the Ti-41Zr-12Nb, Ti-42Zr-11Nb, Ti-43Zr-10Nb, and Ti-44Zr-10Nb alloys, respectively. Ti-41Zr-12Nb alloy demonstrated the highest ductility, with relative elongation to failure of over 20%, combined with the total recovery strain of more than 6%. Obtained results indicate that Ti-41Zr-12Nb is one the most promising alloys of the Ti-Zr-Nb system, with quite perfect superelastic behavior at room temperature.

Superelastic biocompatible alloys attract significant attention as novel materials for bone tissue replacement. These alloys are often composed of three or more components that lead to the formation of complex oxide films on their surfaces. For practical use, it is desirable to have a single-component oxide film with a controlled thickness on the surface of biocompatible material. Herein we investigate the applicability of the atomic layer deposition (ALD) technique for surface modification of Ti-18Zr-15Nb alloy with TiO2 oxide. It was found that a 10–15 nm thick, low-crystalline TiO2 oxide layer is formed by ALD method over the natural oxide film (~5 nm) of the Ti-18Zr-15Nb alloy. This surface consists of TiO2 exclusively without any additions of Zr or Nb oxides/suboxides. Further, the obtained coating is modified by Ag nanoparticles (NPs) with a surface concentration up to 1.6% in order to increase the material’s antibacterial activity. The resulting surface exhibits enhanced antibacterial activity with an inhibition rate of more than 75% against E.coli bacteria.

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