An ab initio study of the structural and mechanical alterations of Ti-Nb alloys
| Autor: | G.A. Evangelakis, J. J. Gutiérrez Moreno, Ch.E. Lekka, D.G. Papageorgiou |
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| Rok vydání: | 2018 |
| Předmět: |
Phase transition
Materials science Alloy Ab initio General Physics and Astronomy Thermodynamics 02 engineering and technology engineering.material 01 natural sciences Biomaterials symbols.namesake Polycrystalline material Ab initio quantum chemistry methods Phase stability 0103 physical sciences Titanium alloys Anisotropy Elastic modulus Elastic stiffness Titanium 010302 applied physics Crystal structure Titanium alloy Transition metals Poisson's ratio 021001 nanoscience & nanotechnology Phase transitions engineering symbols 0210 nano-technology Crystal orientation |
| Zdroj: | Journal of Applied Physics. 124:245102 |
| ISSN: | 1089-7550 0021-8979 |
| Popis: | This article describes a systematic theoretical investigation of the role of Nb substitution on the structural and mechanical properties of Ti-Nb alloys. The aim is to understand the origin of the low-rigidity of some of these materials. This quality makes these materials suitable for metallic implants. The mechanical stability conditions in conjunction with the calculated elastic constants of Ti-Nb predict the destabilization of α′ and ω structures, while the β-phase can be stabilized for Nb content above 10 at. %. The evaluated Young's moduli (E) follow the sequence of Eω > Eα′ > Εα″ > Εβ, revealing high Eω and Eα′ values (greater than 120 GPa), while the Eβ value converges to approximately 87 GPa. The averaged E, estimated from a weighted average of Eω, Eα′, Εα″, and Εβ ab initio values, reproduces the experimental Ti-Nb Young's modulus w-shaped curve. Young's modulus surface reveals highly anisotropic E values for all Ti-Nb phases. Eβ exhibits values under 30 GPa along the [100] direction for Nb compositions larger than 12 at. %, suggesting that the orientational growth of a Ti-Nb alloy is important for the design of low-rigidity alloys, especially at small Nb concentrations. These results can be used as a guide for the design of novel low-rigidity alloys for biomedical applications. |
| Databáze: | OpenAIRE |
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