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Processing and properties of highly porous Ti6Al4V mimicking human bones

  • Jose Luis Cabezas-Villa (a1), Luis Olmos (a1), Didier Bouvard (a2), José Lemus-Ruiz (a3) and Omar Jiménez (a4)...

Ti6Al4V alloy samples with large pores suitable for bone implants are fabricated by pressing and sintering. Ti6Al4V powder is mixed with different volume fractions of salt particles. The sintering behavior up to 1260 °C is studied by dilatometry and pore features are observed by scanning electron microscopy and X-ray microtomography. Sintered materials with a relative density between 0.26 and 0.97 are obtained. 3D image analysis proves that large pores form a connected network when the amount of salt is 20% and above. The Young’s modulus and the yield stress of sintered materials deduced from compression tests span over wide ranges of values, which are consistent with real bone data. A simple analytical model is proposed to estimate the relative density as a function of the fraction of salt. This model combined with classical Gibson and Ashby’s power equations for mechanical properties can predict the fraction of salt required to obtain prescribed properties.

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Contributing Editor: Amit Bandyopadhyay

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1. Dewidar, M.M., Khalil, K.A., and Lim, J.K.: Processing and mechanical properties of porous 316L stainless steel for biomedical applications. Trans. Nonferrous Metals Soc. 17, 468 (2007).
2. Bender, S., Chalivendra, V., Rahbar, N., and El Wakil, S.: Mechanical characterization and modeling of graded porous stainless steel specimens for possible bone implant applications. Int. J. Eng. Sci. 53, 67 (2012).
3. Eriksson, M., Andersson, M., Adolfsson, E., and Carlström, E.: Titanium–hydroxyapatite composite biomaterial for dental implants. Powder Metall. 49, 70 (2006).
4. Rack, H.J. and Qazi, J.: Titanium alloys for biomedical applications. Mater. Sci. Eng., C 26, 1269 (2006).
5. Oksiuta, Z., Dabrowski, J.R., and Olszyna, A.: Co–Cr–Mo-based composite reinforced with bioactive glass. J. Mater. Process. Technol. 209, 978 (2009).
6. Dourandish, M., Godlinski, D., Simchi, A., and Firouzdor, V.: Sintering of biocompatible P/M Co–Cr–Mo alloy (F-75) for fabrication of porosity-graded composite structures. Mater. Sci. Eng., A 472, 338 (2008).
7. Crosby, K.: Titanium–6Aluminum–4Vanadium for functionally graded orthopedic implant applications. Doct. Diss. 218, 1 (2013).
8. Long, M. and Rack, H.: Titanium alloys in total joint replacement—A materials science perspective. Biomaterials 19, 16211639 (1998).
9. Bahraminasab, M., Sahari, B.B., Edwards, K.L., Farahmand, F., Arumugam, M., and Hong, T.S.: Aseptic loosening of femoral components—A review of current and future trends in materials used. Mater. Des. 42, 459 (2012).
10. Niinomi, M. and Nakai, M.: Titanium-based biomaterials for preventing stress shielding between implant devices and bone. Int. J. Biomater. 2011, 10 (2011).
11. Moyen, B.J., Lahey, P.J., Weinberg, E.H., and Harris, W.H.: Effects on intact femora of dogs of the application and removal of metal plates. A metabolic and structural study comparing stiffer and more flexible plates. J. Bone Jt. Surg., Am. 60A, 940 (1978).
12. Wang, X., Xu, S., Zhou, S., Xu, W., Leary, M., Choong, P., and Xie, Y.M.: Topological design and additive manufacturing of porous metals for bone scaffolds and orthopaedic implants: A review. Biomaterials 83, 127 (2016).
13. Gibson, L.J. and Ashby, M.F.: Cellular Solids: Structure and Properties, 2nd ed., Vol. 175 (Cambridge University Press, Cambridge, United Kingdom, 1999).
14. Shen, H. and Brinson, L.C.: A numerical investigation of porous titanium as orthopedic implant material. Mech. Mater. 43, 420 (2011).
15. Karageorgiou, V. and Kaplan, D.: Porosity of 3D biomaterial scaffolds and osteogenesis. Biomaterials 26, 5474 (2005).
16. Takemoto, M., Fujibayashi, S., Neo, M., Suzuki, J., Kokubo, T., and Nakamura, T.: Mechanical properties and osteoconductivity of porous bioactive titanium. Biomaterials 26, 6014 (2005).
17. Oh, I.H., Nomura, N., Masahashi, N., and Hanada, S.: Mechanical properties of porous titanium compacts prepared by powder sintering. Scr. Mater. 49, 1197 (2003).
18. Chino, Y. and Dunand, D.C.: Directionally freeze-cast titanium foam with aligned, elongated pores. Acta Mater. 56, 105 (2008).
19. Li, F., Li, J., Huang, T., Kou, H., and Zhou, L.: Compression fatigue behavior and failure mechanism of porous titanium for biomedical applications. J. Mech. Behav. Biomed. Mater. 65, 814 (2017).
20. Hrabe, N.W., Heinl, P., Flinn, B., Körner, C., and Bordia, R.K.: Compression-compression fatigue of selective electron beam melted cellular titanium (Ti–6Al–4V). J. Biomed. Mater. Res., Part B 99, 313 (2011).
21. Cheng, X.Y., Li, S.J., Murr, L.E., Zhang, Z.B., Hao, Y.L., Yang, R., Medina, F., and Wicker, R.B.: Compression deformation behavior of Ti–6Al–4V alloy with cellular structures fabricated by electron beam melting. J. Mech. Behav. Biomed. Mater. 16, 153 (2012).
22. Parthasarathy, J., Starly, B., Raman, S., and Christensen, A.: Mechanical evaluation of porous titanium (Ti6Al4V) structures with electron beam melting (EBM). J. Mech. Behav. Biomed. Mater. 3, 249 (2010).
23. Liu, Y.J., Li, S.J., Wang, H.L., Hou, W.T., Hao, Y.L., Yang, R., Sercombe, T.B., and Zhang, L.C.: Microstructure, defects and mechanical behavior of beta-type titanium porous structures manufactured by electron beam melting and selective laser melting. Acta Mater. 113, 56 (2016).
24. Sallica-Leva, E., Caram, R., Jardini, A.L., and Fogagnolo, J.B.: Ductility improvement due to martensite α′ decomposition in porous Ti–6Al–4V parts produced by selective laser melting for orthopedic implants. J. Mech. Behav. Biomed. Mater. 54, 149 (2016).
25. Scott-Emuakpor, O., Holycross, C., George, T., Knapp, K., and Beck, J.: Fatigue and strength studies of titanium 6Al–4V fabricated by direct metal laser sintering. J. Eng. Gas Turbines Power 138, 022101 (2016).
26. Krishna, B.V., Bose, S., and Bandyopadhyay, A.: Low stiffness porous Ti structures for load-bearing implants. Acta Biomater. 3, 997 (2007).
27. Furumoto, T., Koizumi, A., Alkahari, M.R., Anayama, R., Hosokawa, A., Tanaka, R., and Ueda, T.: Permeability and strength of a porous metal structure fabricated by additive manufacturing. J. Mater. Process. Technol. 219, 10 (2015).
28. Reig, L., Amigó, V., Busquets, D.J., and Calero, J.A.: Development of porous Ti6Al4V samples by microsphere sintering. J. Mater. Process. Technol. 212, 3 (2012).
29. Torres, Y., Rodríguez, J.A., Arias, S., Echeverry, M., Robledo, S., Amigo, V., and Pavón, J.J.: Processing, characterization and biological testing of porous titanium obtained by space-holder technique. J. Mater. Sci. 47, 6565 (2012).
30. Torres, Y., Pavón, J.J., Nieto, I., and Rodríguez, J.A.: Conventional powder metallurgy process and characterization of porous titanium for biomedical applications. Metall. Mater. Trans. B 42, 891 (2011).
31. Jorgensen, D.J. and Dunand, D.C.: Ti–6Al–4V with micro-and macropores produced by powder sintering and electrochemical dissolution of steel wires. Mater. Sci. Eng., A 527, 849 (2010).
32. Kalantari, S.M., Arabi, H., Mirdamadi, S., and Mirsalehi, S.A.: Biocompatibility and compressive properties of Ti–6Al–4V scaffolds having Mg element. J. Mech. Behav. Biomed. Mater. 48, 183 (2015).
33. Torres, Y., Lascano, S., Bris, J., Pavón, J., and Rodriguez, J.A.: Development of porous titanium for biomedical applications: A comparison between loose sintering and space-holder techniques. Mater. Sci. Eng., C 37, 148 (2014).
34. Aşık, E.E. and Bor, Ş.: Fatigue behavior of Ti–6Al–4V foams processed by magnesium space holder technique. Mater. Sci. Eng., A 621, 157 (2015).
35. Shang, H., Mohanram, A., and Bordia, R.K.: Densification and microstructural evolution of hierarchically porous ceramics during sintering. J. Am. Ceram. Soc. 98, 3424 (2015).
36. Olmos, L., Takahashi, T., Bouvard, D., Martin, C.L., Salvo, L., Bellet, D., and Di Michiel, M.: Analysing the sintering of heterogeneous powder structures by in situ microtomography. Philos. Mag. 89, 2949 (2009).
37. Serra, J.: Image Analysis and Mathematical Morphology (Academic Press, London, 1982).
38. Babin, P., Della Valle, G., Chiron, H., Cloetens, P., Hoszowska, J., Pernot, P., Réguerre, A.L., Salvo, L., and Dendievel, R.: Fast X-ray tomography analysis of bubble growth and foam setting during breadmaking. J. Cereal Sci. 43, 393 (2006).
39. Olmos, L., Martin, C.L., Bouvard, D., Bellet, D., and Di Michiel, M.: Investigation of the sintering of heterogeneous powder systems by synchrotron microtomography and discrete element simulation. J. Am. Ceram. Soc. 92, 1492 (2009).
40. Vagnon, A., Rivière, J.P., Missiaen, J.M., Bellet, D., Di Michiel, M., Josserond, C., and Bouvard, D.: 3D statistical analysis of a copper powder sintering observed in situ by synchrotron microtomography. Acta Mater. 56, 1084 (2008).
41. Marmottant, A., Salvo, L., Martin, C.L., and Mortensen, A.: Coordination measurements in compacted NaCl irregular powders using X-ray microtomography. J. Eur. Ceram. Soc. 28, 2441 (2008).
42. Phani, K.K. and Niyogi, S.K.: Young’s modulus of porous brittle solids. J. Mater. Sci. 22, 257 (1987).
43. Kováčik, J.: Correlation between Young’s modulus and porosity in porous materials. J. Mater. Sci. Lett. 18, 1007 (1999).
44. Nielsen, L.F.: Elasticity and damping of porous materials and impregnated materials. J. Am. Ceram. Soc. 67, 93 (1984).
45. Bandyopadhyay, A., Espana, F., Balla, V.K., Bose, S., Ohgami, Y., and Davies, N.M.: Influence of porosity on mechanical properties and in vivo response of Ti6Al4V implants. Acta Biomater. 6, 1640 (2010).
46. Li, J.P., Habibovic, P., van den Doel, M., Wilson, C.E., de Wijn, J.R., van Blitterswijk, C.A., and de Groot, K.: Bone ingrowth in porous titanium implants produced by 3D fiber deposition. Biomaterials 28, 2810 (2007).
47. Takahashi, Y. and Tabata, Y.: Effect of the fiber diameter and porosity of non-woven PET fabrics on the osteogenic differentiation of mesenchymal stem cells. J. Biomater. Sci., Polym. Ed. 15, 41 (2004).
48. Itälä, A.I., Ylänen, H.O., Ekholm, C., Karlsson, K.H., and Aro, H.T.: Pore diameter of more than 100 μm is not requisite for bone ingrowth in rabbits. J. Biomed. Mater. Res., Part A 58, 679 (2001).
49. Piemme, J.C.: Titanium PM for Orthopedic Implants. World PM2016 Proceedings—Biomedical Applications. Manuscript refereed by Dr. José Manuel Martin (2016).
50. Grimm, M. and Williams, J.: Measurements of permeability in human calcaneal trabecular bone. J. Biomech. 30, 743 (1997).
51. Nauman, E., Fong, K., and Keaveny, T.: Dependence of intertrabecular permeability on flow direction and anatomic site. Ann. Biomed. Eng. 27, 517 (1999).
52. Wen, C.E., Yamada, Y., Shimojima, K., Chino, Y., Asahina, T., and Mabuchi, M.: Processing and mechanical properties of autogenous titanium implant materials. J. Mater. Sci. Mater. Med. 13, 397 (2002).
53. Gagg, G., Ghassemieh, E., and Wiria, F.E.: Effects of sintering temperature on morphology and mechanical characteristics of 3D printed porous titanium used as dental implant. Mater. Sci. Eng., C 33, 3858 (2013).
54. Barui, S., Chatterjee, S., Mandal, S., Kumar, A., and Basu, B.: Microstructure and compression properties of 3D powder printed Ti–6Al–4V scaffolds with designed porosity: Experimental and computational analysis. Mater. Sci. Eng., C 70, 812 (2017).
55. Singh, R., Lee, P.D., Lindley, T.C., Dashwood, R.J., Ferrie, E., and Imwinkelried, T.: Characterization of the structure and permeability of titanium foams for spinal fusion devices. Acta Biomater. 5, 477 (2009).
56. Zhang, Z., Jones, D., Yue, S., Lee, P.D., Jones, J.R., Sutcliffe, C.J., and Jones, E.: Hierarchical tailoring of strut architecture to control permeability of additive manufactured titanium implants. Mater. Sci. Eng., C 33, 4055 (2013).
57. Despois, J.F. and Mortensen, A.: Permeability of open-pore microcellular materials. Acta Mater. 53, 1381 (2005).
58. Dias, M.R., Fernandes, P.R., Guedes, J.M., and Hollister, S.J.: Permeability analysis of scaffolds for bone tissue engineering. J. Biomech. 45, 938 (2012).
59. Camron, H.U., Pilliar, R.M., and Macnab, I.: The rate of bone ingrowth into porous metal. J. Biomed. Mater. Res., Part A 10, 295 (1976).
60. Bobyn, J.D., Pilliar, R.M., Cameron, H.U., and Weatherly, G.C.: The optimum pore size for the fixation of porous-surfaced metal implants by the ingrowth of bone. Clin. Orthop. Relat. Res. 150, 263 (1980).
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