Metsintez LLC, Tula, Russia:

A. V. Kasimtsev, Director, e-mail: metsintez@yandex.ru
S. N. Yudin, Head of the Process Office, e-mail: Sergey-USN@mail.ru

Tula State University, Tula, Russia:
S. S. Volodko, Post-Graduate Student, Chair of Physics of Metals and Science of Materials, e-mail: volodko.sv@yandex.ru

A. A. Baikov Institute of Metallurgy and Material Science of the Russian Academy of Sciences, Moscow, Russia:
A. V. Alpatov, Senior Research Officer, Laboratory of Material Diagnostics (No. 17), e-mail: alpat72@mail.ru

Presented in the paper are the results of investigating the consolidation process (compacting, sintering, hot isostatic pressing – HIP) of calcium hydride powder of low modulus Ti – Nb alloys doped by tantalum: Ti – 30.1 wt.% Nb – 17.4 wt.% Ta (Ti – 22 at.% Nb – 6 at.% Ta), zirconium: Ti – 33.2 wt.% Nb – 8.6 wt.% Zr (Ti – 22 at.% Nb – 6 at.% Zr) and estimating their mechanical properties. It is shown that metal powders are notable for good compactability on both single-action compacting and isostatic forming. Cold isostatic forming under pressure of 200 MPa permits to obtain briquettes with relative density of 65–68%. Sintering the briquettes at a temperature of 1873 K provides blank formation with porosity of 16 and 8% for Ti – 30.1Nb – 17.4Ta, Ti – 33.2Nb – 8.6Zr (wt.%) alloys, respectively. Sintering in vacuum of 1.33 Pa leads to formation of a gas-filled layer with heightened microhardness to a depth of 8 mm. Sintering in vacuum of 1.33·10–2 Pa allows to avoid this phenomenon. Hot isostatic pressing of the sintered blanks at a temperature of 1193 K and pressure of 150 MPa guarantees obtaining practically porousless material (1% of pores). It is determined that Ti – 30.1Nb – 17.4Ta, Ti – 33.2Nb – 8.6Zr (wt.%) are characterized after sintering by the following values of the yield stress and the Young’s modulus: σ_0.2 = 444 ± 7 MPa, E = 57 ± 5 GPa and σ_0.2 = 570 ± 29 MPa, E = 62 ± 5 GPa, respectively. After HIP: σ_0.2 = 791 ± 16 MPa, E = 87 ± 4 GPa and σ_0.2 = 750 ± 50 MPa, E = 81 ± 1 GPa, respectively.

The work was financially supported by the Russian Foundation for Basic Research (Project No. 16-43-710688 р_а). Determination of hydrogen content is performed within the framework of the State task No. 007-00129-18-00.

1. Niinomi M. Recent research and development in titanium alloys for biomedical applications and healthcare goods. Science and Technology of Advanced Materials. 2003. Vol. 4. pp. 445–454.
2. Balazic M., Kopac J., Jackson M. J., Ahmed W. Review: titanium and titanium alloy applications in medicine. International Journal of Nano and Biomaterials. 2007. Vol. 1, No. 1. pp. 3–34.
3. Brailovski V., Prokoshkin S., Gauthier M., Inaekyan K., Dubinskiy S., Petrzhik M., Filonov M. Bulk and porous metastable beta Ti – Nb – Zr(Ta) alloys for biomedical applications. Materials Science and Engineering: C. 2011. Vol. 31. pp. 643–657.
4. Ahmed T., Rack H. J. Low modulus biocompatible titanium base alloys for medical devices: Pat. 5871595 (USA). 1999.

5. Eisenbarth E., Velten D., Müller M., Thull R., Breme J. Biocompatibility of β-stabilizing elements of titanium alloys. Biomaterials. 2004. Vol. 25. pp. 5705–5713.
6. Kuroda D., Niinomi M., Morinaga M., Kato Y., Yashiro T. Design and mechanical properties of new β-type titanium alloys for implant materials. Materials Science and Engineering: A. 1998. Vol. 243. pp. 244–249.
7. Matsuno H., Yokoyama A., Watari F., Uo M., Kawasaki T. Biocompatibility and osteogenesis of refractory metal implants, titanium, hafnium, niobium, tantalum and rhenium. Biomaterials. 2001. Vol. 22. pp. 1253–1262.
8. Sun J., Yao Q., Xing H., Guo W. Y. Elastic properties of β, α^'' and ω metastable phases in Ti–Nb alloy from first-principles. Journal of Physics: Condensed Matter. 2007. Vol. 19. No. 48. pp. 1–8.
9. Ikehata H., Nagasako N., Furuta T., Fukumoto A., Miwa K., Saito T. First-principles calculations for development of low elastic modulus Ti alloys. Physical Review B. 2004. Vol. 70. pp. 174113-1–174113-8.
10. Gutiérrez Moreno J. J., Bönisch M., Panagio topoulos N. T., Calin M., Papageorgiou D. G., Gebert A., Eckert J., Evangelakis G. A., Lekka Ch. E. Ab-initio and experimental study of phase stability of Ti – Nb alloys. Journal of Alloys and Compounds. 2017. Vol. 696. pp. 481–489.

11. Gasik M. M., Yu H. Phase Equilibria and Thermal Behaviour of Biomedical Ti – Nb – Zr Alloy. 17^th Plansee Seminar 2009 — International Conference on High Performance P/M Materials (25–29 May 2009) : proceedings and seminar impressions. Reutte, 2009. Vol. 1. pp. 29/1–29/7.
12. Na L., Warnes W. H. Estimation of the Nb – Ti – Ta Phase Diagram. IEEE Transactions on Applied Superconductivity. 2001. Vol. 11. No. 1. pp. 3800–3803.
13. Collings E. W. Applied Superconductivity, Metallurgy, and Physics of Titanium Alloys: Their Metallurgical, Physical, and Magnetic-Mixed-State Properties. Springer Science & Business Media, 2013. 834 p.
14. Souza S. A., Manicardi R. B., Ferrandini P. L., Afonso C. R. M., Ramirez A. J., Caram R. Effect of the addition of Ta on microstructure and properties of Ti – Nb alloys. Journal of Alloys and Compounds. 2010. Vol. 504. pp. 330–340.
15. Konopatskii A. S., Zhukova Yu. S., Dubinskii S. M., Korobkova A. A., Filonov M. R., Prokoshkin S. D. Microstructure of Superplastic Alloys Based on Ti–Nb for medical purposes. Metallurgist. 2016. Vol. 60, Nos. 1–2. pp. 223–228.
16. Konopatsky A., Zhukova Yu., Dubinsky S., Filonov M., Prokoshkin S. Production of Novel Superelastic Biocompatible Ti – Nb-based Alloys for Medical Application. ESOMAT 2015 — 10^th European Symposium on Martensitic Transformations. MATEC Web of Conferences (14–18 September, 2015) : proceedings. Belgium: EDP Sciences. 2015. Vol. 33. p. 06003-p.1-06003-p.5.
17. Martins D. Q., Os rio W. R., Souza M. E. P., Caram R., Garcia A. Effects of Zr content on microstructure and corrosion resistance of Ti – 30Nb – Zr casting alloys for biomedical applications. Electrochimica Acta. 2008. Vol. 53. pp. 2809–2817.
18. Kasimtsev A. V., Shuytsev A. V., Yudin S. N., Levinskyi Yu. V., Sviridova T. A., Alpatov A. V., Novosvetlova E. E. Hydrid-calcium synthesis of powders of Ti – Nb-based. Metally. 2017. No. 5. pp. 52–63.
19. Shelekhov E. V., Sviridova T. A. Programs for X-ray Analysis of Polycrystals. Metal Science and Heat Treatment. 2000. Vol. 42. No. 8. pp. 309–313.
20. Robertson I. M., Schaffer G. B. Review of densification of titanium based powder systems in press and sinter processing. Powder Metallurgy. 2010. Vol. 53. No. 2. pp. 146–162.
21. Kang S. J. L. Sintering: densification, grain growth and microstructure. Elsevier Butterworth-Heinemann, 2004. 265 p.
22. Eremenko V. N., Tretyachenko L. A. Triple titanium systems with transition metals of IV–VI groups. Kiev: Naukova Dumka, 1987. 232 p.
23. Zhukova Yu. S. Production and characterization of superelastic Ti – Nb – Ta, Ti – Nb – Zr alloys fro medical applications: thesis of inauguration of Dissertation … of Candidate of Engineering Sciences. Moscow: MISiS, 2013. 23 p.
24. Liu Z., Welsch G. Effects of Oxygen and Heat Treatment on the Mechanical Properties of Alpha and Beta Titanium Alloys. Metallurgical Transactions: A. 1988. Vol. 19. pp. 527–542.
25. Malinov S., Zhecheva A., Sha W. Relation between the Microstructure and Properties of Commercial Titanium Alloys and the Parameters of Gas Nitriding. Metal Science and Heat Treatment. 2004. Vol. 46. Nos. 7–8. pp. 286–293.
26. Moffat D. L., Larbalestier D. C. The Competition between the Alpha and Omega Phases in Aged Ti – Nb Alloys. Metallurgical Transactions: A. 1988. Vol. 19. pp. 1687–1694.
27. Koul M. K., Breedis J. F. Phase Transformations in Beta Isomorphous Titanium Alloys. Acta Metallurgica. 1970. Vol. 18. pp. 579–588.
28. Afonso C. R. M., Ferrandini P. L., Ramirez A. J., Caram R. High resolution transmission electron microscopy study of the hardening mechanism through phase separation in a β – Ti – 35Nb – 7Zr – 5Ta alloy for implant applications. Acta Biomaterialia. 2010. Vol. 6. pp. 1625–1629.
29. Atkinson H. V., Davies S. Fundamental Aspects of Hot Isostatic Pressing: An Overview. Metallurgical and Materials Transactions: A. 2000. Vol. 31. pp. 2981–3000.