Microstructure and mechanical properties of spark plasma sintered Ti-Mo alloys for dental applications

Abstract

Ti-Mo alloys with various Mo contents from 6wt% to 14wt% were processed by spark plasma sintering based on elemental powders. The influence of sintering temperature and Mo content on the microstructure and mechanical properties of the resulting alloys were investigated. For each Mo concentration, the optimum sintering temperature was determined, resulting in a fully dense and uniform microstructure of the alloy. The optimized sintering temperature gradually increases in the range of 1100–1300°C with the increase in Mo content. The microstructure of the Ti-(6–12)Mo alloy consists of acicular α phase surrounded by equiaxed grains of β phase, while the Ti-14Mo alloy only contains single β phase. A small amount of fine α lath precipitated from β phase contributes to the improvement in strength and hardness of the alloys. Under the sintering condition at 1250°C, the Ti-12Mo alloy is found to possess superior mechanical properties with the Vickers hardness of Hv 472, the compressive yield strength of 2182 MPa, the compression rate of 32.7%, and the elastic modulus of 72.1 GPa. These results demonstrate that Ti-Mo alloys fabricated via spark plasma sintering are indeed a perspective candidate alloy for dental applications.

Keywords

titanium alloys / spark plasma sintering / microstructure / mechanical properties

References

[1] Long M, Rack HJ. Titanium alloys in total joint replacement: a materials science perspective. Biomaterials, 1998, 19(18): 1621.

[2] Niinomi M. Mechanical properties of biomedical titanium alloys. Mater. Sci. Eng. A, 1998, 243(1–2): 231.

[3] Akman E, Demir A, Canel T, Sınmazçelik T. Laser welding of Ti6Al4V titanium alloys. J. Mater. Process. Technol., 2009, 209(8): 3705.

[4] Seshacharyulu T, Dutta B. Influence of prior deformation rate on the mechanism of β→α+β transformation in Ti-6Al-4V. Scripta Mater., 2002, 46(9): 673.

[5] Zhou YL, Luo DM. Corrosion behavior of Ti-Mo alloys cold rolled and heat treated. J. Alloys Compd., 2011, 509(21): 6267.

[6] Kuroda D, Niinomi M, Morinaga M, Kato Y, Yashiro T. Design and mechanical properties of new β type titanium alloys for implant materials. Mater. Sci. Eng. A, 1998, 243(1–2): 244.

[7] Ho WF, Ju CP, Chern Lin JH. Structure and properties of cast binary Ti-Mo alloys. Biomaterials, 1999, 20(22): 2115.

[8] Takekawa J, Sakurai N. Effect of the processing conditions on density, strength and microstructure of Ti-12Mo alloy fabricated by PIM process. J. Jpn. Soc. Powder Powder Metall., 1999, 46(8): 877.

[9] Liu Y, Wei WF, Zhou KC, Chen LF, Tang HP. Microstructures and mechanical behavior of PM Ti-Mo alloy. J. Cent. South Univ. Technol., 2003, 10(2): 81.

[10] Kim YW, Lee YJ, Nam TH. Shape memory characteristics of Ti-Ni-Mo alloys sintered by sparks plasma sintering. J. Alloys Compd., 2013, 577(1): S205.

[11] Li YY, Zou LM, Yang C, Li YH, Li LJ. Ultrafine-grained Ti-based composites with high strength and low modulus fabricated by spark plasma sintering. Mater. Sci. Eng. A, 2013, 560, 857.

[12] Nicula R, Lüthen F, Stir M, Nebe B, Burkel E. Spark plasma sintering synthesis of porous nanocrystalline titanium alloys for biomedical applications. Biomol. Eng., 2007, 24(5): 564

[13] Ibrahim A, Zhang F, Otterstein E, Burkel E. Processing of porous Ti and Ti5Mn foams by spark plasma sintering. Mater. Des., 2011, 32(1): 146.

[14] Xie GQ, Qin FX, Zhu SL, Inoue A. Ni-free Ti-based bulk metallic glass with potential for biomedical applications produced by spark plasma sintering. Intermetallics, 2012, 29, 99.

[15] Thibon I, Ansel D, Boliveau M, Debuigne J. Interdiffusion in the β Mo-Ti solid solution at high temperatures. Mater. Res. Adv. Tech., 1998, 89, 187

[16] Feng L, Li JS, Huang L, Chang H, Cui YW, Zhou L. Interdiffusion behavior of Ti-Mo binary system in β phase. Chin. J. Nonferrous Met., 2009, 19(10): 1766

[17] Bolzoni L, Esteban PG, Ruiz-Navas EM, Gordo E. Mechanical behaviour of pressed and sintered titanium alloys obtained from prealloyed and blended elemental powders. J. Mech. Behav. Biomed. Mater., 2012, 14, 29.

[18] Majumdar P, Singh SB, Chakraborty M. The role of heat treatment on microstructure and mechanical properties of Ti-13Zr-13Nb alloy for biomedical load bearing applications. J. Mech. Behav. Biomed. Mater., 2011, 4(7): 1132.

[19] Delvat E, Gordin DM, Gloriant T, Duval JL, Nagel MD. Microstructure, mechanical properties and cytocompatibility of stable beta Ti-Mo-Ta sintered alloys. J. Mech. Behav. Biomed. Mater., 2008, 1(4): 345.

[20] Almeida A, Gupta D, Loable C, Vilar R. Laser-assisted synthesis of Ti-Mo alloys for biomedical applications. Mater. Sci. Eng. C, 2012, 32(5): 1190.

[21] Niinomi M, Nakai M, Hieda J. Development of new metallic alloys for biomedical applications. Acta Biomater., 2012, 8(11): 3888.

[22] Zhou YL, Luo DM. Microstructures and mechanical properties of Ti-Mo alloys cold-rolled and heat treated. Mater. Charact., 2011, 62(10): 931.

[23] Geng F, Niinomi M, Nakai M. Observation of yielding and strain hardening in a titanium alloy having high oxygen content. Mater. Sci. Eng. A, 2011, 528(16–17): 5435.