First principles theoretical investigations of low Young's modulus beta Ti–Nb and Ti–Nb–Zr alloys compositions for biomedical applications

• Published in: Materials Science & Engineering C 2015-05, Vol.50, p.52-58
• Main Authors: Karre, Rajamallu, Niranjan, Manish K., Dey, Suhash R.
• Format: Article
• Language: English
• Subjects: Ab-initio calculations; Alloy design; Alloy systems; Alloys - chemistry; Anisotropy; Biocompatibility; Biomedical; Biomedical Technology - methods; Density functional theory; Elastic Modulus; Elastic properties; Humans; Mathematical analysis; Modulus of elasticity; Phase stability-prediction; Shear Strength; Surgical implants; Ternary systems; Thermodynamics; Titanium; Titanium - chemistry; Titanium base alloys
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/j.msec.2015.01.061

High alloyed β-phase stabilized titanium alloys are known to provide comparable Young's modulus as that to the human bones (~30GPa) but is marred by its high density. In the present study the low titanium alloyed compositions of binary Ti–Nb and ternary Ti–Nb–Zr alloy systems, having stable β-phase with low Young's modulus are identified using first principles density functional framework. The theoretical results suggest that the addition of Nb in Ti and Zr in Ti–Nb increases the stability of the β-phase. The β-phase in binary Ti–Nb alloys is found to be fully stabilized from 22at.% of Nb onwards. The calculated Young's moduli of binary β-Ti–Nb alloy system are found to be lower than that of pure titanium (116GPa). For Ti–25(at.%)Nb composition the calculated Young's modulus comes out to be ~80GPa. In ternary Ti–Nb–Zr alloy system, the Young's modulus of Ti–25(at.%)Nb–6.25(at.%)Zr composition is calculated to be ~50GPa. Furthermore, the directional Young's moduli of these two selected binary (Ti–25(at.%)Nb) and ternary alloy (Ti–25(at.%)Nb–6.25(at.%)Zr) compositions are found to be nearly isotropic in all crystallographic directions. •First principles calculations (DFT) are used on Ti–Nb and Ti–Nb–Zr alloy systems.•Predicted compositions having stable β phase with low Young's modulus.•Many possible structural configurations within these alloy systems are considered.•Directional Young's modulus is studied to know anisotropy of the compositions.