Influence of alloying elements Nb, Zr, Sn, and oxygen on structural stability and elastic properties of the Ti2448 alloy

Abstract

The mechanisms of how alloying elements and oxygen influence the stability and elastic properties of binary Ti-X (X = Nb, Zr, or Sn) and Ti2448 (Ti-24Nb-4Zr-8Sn in wt.%) alloys are studied via first principles calculations. In addition to the fully disordered solid solution phase, we consider 44 quasirandom configurations to search for the possible distributions of the alloying elements in Ti2448. Our results show that all alloying elements considered here are good β-stabilizers for Ti, and the formation energies are greatly affected by their distributions. The site preference of oxygen and its concentration dependence in binary Ti alloys and in Ti2448 are also investigated. Oxygen prefers to occupy the octahedral site regardless of the concentrations of the alloys and strongly interacts with Ti and Nb in Ti-Nb. The elastic properties of Ti2448 alloy and the influence of oxygen on the elastic parameters are evaluated. The calculated polycrystalline Young's modulus of the Ti2448 alloy is very close to that of the human bone (10-40 GPa). We find that oxygen has a weak effect on the elastic moduli of Ti2448. The electronic structures are analyzed to reveal how the alloying elements and oxygen influence the stability of binary Ti-X and Ti2448 alloys.

On the high-pressure phase stability and elastic properties ofβ-titanium alloys

“…On the other hand, we note that deliberate addition of oxygen appears to have little effect on the stability with respect to pressure of alloys which are already in the β phase at ambient conditions; both Ti-13.5Mo-0.26O and Ti-13.5Mo-0.40O were stable to their highest studied pressure with no secondary phases emerging (figure 2) and, for a second-order EOS ( ′ B 0 fixed at 4), their compressibilities are comparable within error. This finding reinforces the conclusions of a recent ab initio study on binary Ti alloys Ti-X (X = Nb, Zr and Sn-known β-stabilisers) and on Ti2448, which suggest O as having only a small effect on elastic properties in these alloys [33]. For third-order BM EOS, the bulk modulus obtained from our measurements is significantly higher for Ti-13.5Mo-0.40O than for Ti-13.5Mo-0.26O (table 2), but it is likely that this is correlated to some extent with the value of ′ B 0 which is much lower for Ti-13.5Mo-0.4O.…”

Corrosion and Biological Behaviors of Biomedical Ti–24Nb–4Zr–8Sn Alloy under an Oxidative Stress Microenvironment

“…As a powerful β-stabilizer, Nb significantly enhanced the biomechanical properties of Ti. 34 The content of Nb improved the corrosion resistance of the binary Nb−Zr alloy system. 35 The addition of Zr enhances the stability of the β-phase and bolsters corrosion resistance compared with the Ti-22Nb alloy.…”

“…The corrosion resistance of alloys affects their biocompatibility and long-term mechanical stability, potentially resulting in implant failure. As a powerful β-stabilizer, Nb significantly enhanced the biomechanical properties of Ti . The content of Nb improved the corrosion resistance of the binary Nb–Zr alloy system .…”

Exploration of stable stoichiometries, physical properties and hardness in the Rh–Si system: a first-principles study

“…The bulk modulus (B) and shear modulus (G) are directly derived from the calculated elastic constants by using the Voigt-Reuss-Hill method, 30 and the results are tabulated in Table 3. The Young's modulus (E) and the Poisson's ratio (ν) can also be calculated from B and G using the following formulae:…”