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MM: Fachverband Metall- und Materialphysik

MM 47: Poster Session II

MM 47.9: Poster

Mittwoch, 14. März 2018, 18:30–19:45, Poster C

First-principles design of biocompatible Ti-xNb (0 < x< 35) alloys — •Julio Gutierrez Moreno^1,2, Dimitris Papageorgiou², Giorgios Evangelakis³, and Christina Lekka² — ¹Tyndall National Institute, University College Cork — ²Departament of Materials Science and Engineering, University of Ioannina — ³Departament of Physics, University of Ioannina

In this work, we present a systematic ab initio study on the structural, electronic and mechanical properties of Ti-xNb (x<35at%) alloys. This necessity is originated from the lack of biocompatibility and high Young's modulus (E) in the currently used Ti-6Al-4V implants, which may lead to bone atrophy and implant loosening. Our results predict a variety of phases (including ω, α', α' and β) depending on the Nb concentration. The α' and ω are stable for Nb<6.25%at, the β phase is stable at high Nb compositions Nb>18.75at% while the α" phase may form in intermediate concentrations. The α' and ω hexagonal phases become unstable at high Nb content due to the electronic band filling at the Fermi level. In β-Ti-25at%Nb, the depletion of the occupied electronic states at Fermi level results in a stable β-TiNb structure. Our results prove the Eω>Eα'>Εα">Εβ sequence, revealing the importance of the phases coexistence for the E reduction. The Young's modulus surface revealed high anisotropic E values for all Ti-Nb phases, while the Eβ along the [100] direction exhibits E<30GPa. These data could enlighten the electronic origin of the Ti-Nb phase stability and guide the design of novel alloys suitable for biomedical applications.