OBRABOTKA METALLOV

Introduction. Ti-40 wt. % Nb (Ti-40Nb) is a non-conventional material for medical applications as it has low modulus of elasticity (50-60 GPa) which is of great importance for the mechanical compatibility of an implant with bone tissue. The progressive methods productions of finished items on Ti-40Nb alloy are severe plastic deformation (SPD) and selective laser melting (SLM). These methods have different nature and influence on phase composition, structure and properties of finished item. Due to this fact rigorous structural researches are required. Aim of present study is evaluation of structural characteristics of Ti-40Nb alloy produced in conditions of high-energy influence via SPD and SLM methods, taking into account heterogeneity of elemental composition, which is caused by the structure formation conditions. Object of research. Alloy ingots were produced via electro-arc melting. SPD of quenched ingots was carried out via combined method including subsequent operations of pressing to symmetric channel, multiaxial forging and rolling. SLM of mechanically alloyed powder was carried out with VARISKAF-100MVS installation. Research methods. Specimens’ structure was studied with the methods of optical and scanning electron microscopy, energy-dispersive microanalysis, X-ray diffraction analysis. Elastic modulus and nanohardness were estimated via unrestored print method. Results. It is shown that in the process of ingot’s crystallization dendritic structure, consisting of β-phase with intracrystalline segregation and Nb concentration’s difference up to 6 wt. %, is formed. After ingot’s quenching α''-phase’s martensite structure is formed in Nb-depleted zones. Ingot’s SPD leads to the elimination of segregation, to the reverse α'' → β + α transformation and to the formation of ultrafinegrained structure with the optimal complex of physical mechanical properties required for the implants production. SLM forms structure, consisting of β-phase grains of micron size with interlays of nonequilibrium α''-phase throughout the grains’ boundaries. It is proposed to remove the formed in the alloy intracrytalline segregation with the difference of Nb concentrations up to 27 wt. % via subsequent thermal treatment. Conclusion. Two considered high-energy methods of medical implants production, which are SPD and SLM, have significant influence on the structure of Ti-40Nb alloy. Character of the influence is defined with the method by itself and with the formed heterogeneity of elemental composition.

1.   Zhao D., Chang K., Ebel T., Nie H., Willumeit R., Pyczak F. Microstructure and mechanical behavior of metal injection molded Ti-Nb binary alloy as biomedical material. Journal of the Mechanical Behavior of Biomedical Materials, 2013, vol. 28, pp. 171–182. DOI: 10.1016/j.jmbbm.2013.08.013.

2.   Niinomi M., Nakai M., Hieda J. Development of new metallic alloys for biomedical applications. Acta Biomaterialia, 2012, vol. 8, iss. 11, pp. 3888–3903. DOI: 10.1016/j.actbio.2012.06.037.

3.   Xu L., Xiao S.L., Tian J., Chen Y., Huang Y. Microstructure and dry wear properties of Ti-Nb alloys for dental prostheses. Transactions of Nonferrous Metals Society of China, 2009, vol. 19, iss. 3, pp. 639–644. DOI: 10.1016/S1003-6326(10)60124-0.

4.   Sharkeev Yu., Komarova E., Sedelnikova M., Sun Z., Zhu Q., Zhang J., Tolkacheva T., Uvarkin P. Structure and properties of micro-arc calcium phosphate coatings on pure titanium and Ti-40Nb alloy. Transactions of Nonferrous Metals Society of China, 2017, vol. 27, iss. 1, pp. 125–133. DOI: 10.1016/S1003-6326(17)60014-1.

5.   Cremasco A., Osório W.R., Freire C.M.A., Garcia A., Caram R. Electrochemical corrosion behavior of a Ti-35Nb alloy for medical prostheses. Electrochimica Acta, 2008, vol. 53, iss. 14, pp. 4867–4874. DOI: 10.1016/j.electacta.2008.02.011.

6.   Ozaki T., Matsumoto H., Watanabe S., Hanada S. Beta Ti alloys with low Young’s modulus. Materials Transactions, 2004, vol. 45, iss. 8, pp. 2776–2779. DOI: 10.2320/matertrans.45.2776.

7.   Niinomi M., Liu Y., Nakai M., Liu H., Li H. Biomedical titanium alloys with Young’s moduli close to that of cortical bone. Regenerative Biomaterials, 2016, vol. 3, iss. 3, pp. 173–185. DOI: 10.1093/rb/rbw016.

8.   Moffat D.L., Kattner U.R. The stable and metastable Ti-Nb phase diagrams. Metallurgical Transactions A, 1988, vol. 19, iss. 10, pp. 2389–2397. DOI: 10.1007/BF02645466.

9.   Andreev A.L., Anoshkin N.F., Bochvar G.A., et al. Plavka i lit'e titanovykh splavov. Titanovye splavy [Melting of titanium alloys. Titanium alloys]. Moscow, Metallurgiya Publ., 1994. 368 p.

10. Gubkin I.N. Zametki o tekhnologii vyplavki i pererabotki Nb-Ti slitkov v prutki [Notes about technology of melting and processing of Nb-Ti ingots into rods]. Moscow, VNIINM Publ., 2006. 115 p.

11. Ozaltin K., Chrominski W., Kulczyk M., Panigrahi A., Horky J., Zehetbauer M., Lewandowska M. Enhancement of mechanical properties of biocompatible Ti-45Nb alloy by hydrostatic extrusion. Journal of Materials Science, 2014, vol. 49, iss. 20, pp. 6930–6936. DOI: 10.1007/s10853-014-8397-7.

12. Panigrahia A., Sulkowskia B., Waitza T., Ozaltinc K., Chrominskic W., Pukenasd A., Horkya J., Lewandowskac M., Skrotzkid W., Zehetbauera M. Mechanical properties, structural and texture evolution of biocompatible Ti-45Nb alloy processed by severe plastic deformation. Journal of the Mechanical Behavior of Biomedical Materials, 2016, vol. 62, pp. 93–105. DOI: 10.1016/j.jmbbm.2016.04.042.

13. Völker B., Jäger N., Calin M., Zehetbauer M., Eckert J., Hohenwarter A. Influence of testing orientation on mechanical properties of Ti45Nb deformed by high pressure torsion. Materials and Design, 2017, vol. 114, pp. 40–46. DOI: 10.1016/j.matdes.2016.10.035.

14. Panigrahi A., Bönisch M., Waitz T., Schafler E., Calin M., Eckert J., Skrotzki W., Zehetbauer M. Phase transformations and mechanical properties of biocompatible Ti-16.1Nb processed by severe plastic deformation. Journal of Alloys and Compounds, 2015, vol. 628, pp. 434–441. DOI: 10.1016/j.jallcom.2014.12.159

15. Ma J., Karaman I., Kockar B., Maier H.J., Chumlyakov Y.I. Severe plastic deformation of Ti74Nb26 shape memory alloys. Materials Science and Engineering: A, 2011, vol. 528, iss. 25–26, pp. 7628–7635. DOI: 10.1016/j.msea.2011.06.051.

16. Cojocaru V.D., Raducanu D., Gloriant T., Cinca I. Texture evolution in a Ti-Ta-Nb alloy processed by severe plastic deformation. JOM, 2012, vol. 64, iss. 5, pp. 572–581. DOI: 10.1007/s11837-012-0312-6.

17. Li Y., Yang C., Zhao H., Qu S., Li X., Li Y. New Developments of Ti-based alloys for biomedical applications. Materials, 2014, vol. 7, iss. 3, pp. 1709–1800. DOI: 10.3390/ma7031709.

18. Shahali H., Jaggessar A., Yarlagadda P. Kdv. Recent advances in manufacturing and surface modification of titanium orthopaedic applications. Procedia Engineering, 2017, vol. 174, pp. 1067–1076. DOI: 10.1016/j.proeng.2017.01.259.

19. Zhuravleva K., Bönisch M., Prashanth K.G., Hempel U., Helth A., Gemming T., Calin M., Scudino S., Schultz L., Eckert J., Gebert A. Production of porous β-type Ti-40Nb alloy for biomedical applications: comparison of selective laser melting and hot pressing. Materials, 2013, vol. 6, iss. 12, pp. 5700–5712. DOI: 10.3390/ma6125700.

20. Schwab H., Prashanth K.G., Lober L., Kuhn U., Eckert J. Selective laser melting of Ti-45Nb alloy. Materials, 2015. vol. 5, iss. 2, pp. 686–694. DOI: 10.3390/met5020686.

21. Nikonov A.Yu., Zharmukhambetova A.M., Ponomareva A.V., Dmitriev A.I. Numerical study of mechanical properties of nanoparticlesof β-type Ti-Nb alloy under conditions identical to laser sintering. Multilevel approach. Physical Mesomechanics, 2018, vol. 21, no. 1, pp. 43–51.

22. Kolken H.M.A., Janbaz Sh., Leeflang S.M.A., Lietaert K., Weinans H.H., Zadpoor A.A. Rationally designed meta-implants: a combination of auxetic and conventional meta-biomaterials. Materials Horizons, 2018, vol. 5, iss. 1, pp. 28–35. DOI: 10.1039/c7mh00699c.

23. Zhang B., Pei X., Zhou C., Fan Y., Jiang Q., Ronca A., D'Amora U., Chen Y., Li H., Sun Y., Zhang X. The biomimetic design and 3D printing of customized mechanical properties porous Ti6Al4V scaffold for load-bearing bone reconstruction. Materials and Design, 2018, vol. 152, pp. 30–39. DOI: 10.1016/j.matdes.2018.04.065.

24. Kovalevskaya Zh.G., Khimich M.A., Belyakov A.V., Shulepov I.A. Evaluation of physical and mechanical properties of structural components of Ti-Nb alloy. Advanced Materials Research, 2014, vol. 1040, pp. 39–42. DOI: 10.4028/www.scientific.net/AMR.1040.39.

25. Sharkeev Yu.P., Eroshenko A.Yu., Kovalevskaya Zh.G., Saprykin A.A., Ibragimov E.A., Glukhov I.A., Khimich M.A., Uvarkin P.V., Babakova E.V. Structural and phase state of Ti-Nb alloy at selective laser melting of the composite powder. Russian Physics Journal, 2016, vol. 59, iss. 3, pp. 430–434. DOI: 10.1007/s11182-016-0790-z.

26. Sharkeev Yu.P., Kovalevskaya Zh.G., Khimich M.A., Ibragimov E.A., Saprykin A.A., Yakovlev V.I., Bataev V.A. Investigation of the structure and phase composition of Ti and Nb powders after mechanical activation. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2016, no. 1 (70), pp. 42–51. DOI: 10.17212/1994-6309-2016-1-42-51. (In Russian).

27. Sharkeev Yu.P., Eroshenko A.Yu., Glukhov I.A., Zhu Q., Tolmachev A.I. Microstructure and mechanical properties of Ti40Nb alloy after severe plastic deformation. AIP Conference Proceedings, 2014, vol. 1623, iss. 1, pp. 567–570. DOI: 10.1063/1.4899008.

28. Zherebtsova S., Kudryavtseva E., Kostjuchenkova S., Malyshevab S., Salishcheva G. Strength and ductility-related properties of ultrafine grained two-phase titanium alloy produced by warm multiaxial forging. Materials Science and Engineering A, 2012, vol. 536, pp. 190–196. DOI: 10.1016/j.msea.2011.12.102.

29. Savchenko N.L., Vorontsov A.V., Utyaganova V.R., Eliseev A.A., Rubtsov V.E., Kolubaev E.A. Features of the structural-phase state of the alloy Ti-6Al-4V in the formation of products using wire-feed electron beam additive manufacturing. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2018, vol. 20, no. 4, pp. 60–71. DOI: 10.17212/1994-6309-2018-20.4-60-71. (In Russian).

30. Cantor B. Rapidly quenched metals III. Brighton, Metals Society, 1978. 470 p.

31. Sabirov I., Perez-Prado M.T., Molina-Aldareguia J.M., Semenova I.P., Salimgareeva G.Kh., Valiev R.Z. Anisotropy of mechanical properties in high-strength ultra-fine-grained pure Ti processed via a complex severe plastic deformation route. Scripta Materialia, 2011, vol. 64, iss. 1, pp. 69–72. DOI: 10.1016/j.scriptamat.2010.09.006.

32. Meredith C.S., Khan A.S. Texture evolution and anisotropy in the thermo-mechanical response of UFG Ti processed via equal channel angular pressing. International Journal of Plasticity, 2012, vol. 30, pp. 202–217. DOI: 10.1016/j.ijplas.2011.10.006.

33. Kim Y., Ikehara Y., Kim J.I., Yosoda H., Miyazaaki S. Martensitic transformation, shape memory effect and superelasticity of Ti-Nb binary alloys. Acta Materialia, 2006, vol. 54, iss. 9, pp. 2419–2429. DOI: 10.1016/j.actamat.2006.01.019.

34. Afonso C.R.M., Aleixo G.T., Ramirez A.J., Caram R. Influence of cooling rate on microstructure of Ti-Nb alloy for orthopedic implants. Materials Science and Engineering: C, 2007, vol. 27, iss. 4, pp. 908–913. DOI: 10.1016/j.msec.2006.11.001.

35. Reck A., Pilz S., Thormann U., Alt V., Gebert A., Calin M., Heiss C., Zimmermann M. Effects of thermomechanical history and environment on the fatigue behavior of (β)-Ti-Nb implant alloys. MATEC Web of Conferences, 2018, vol. 165, p. 06001. DOI: 10.1051/matecconf/201816506001.

36. Brandon D., Kaplan W.D. Microstructural characterization of materials. New York, John Wiley and Sons, 2013. 552 p.