Porosity and Tensile Properties of Rhizoid Porous Structure Fabricated Using Selective Laser Melting
Shinji Ishibashi*1, Keita Shimada*1, Hiroyasu Kanetaka*2,*3, Masaki Tsukuda*1, Takumi Mizoi*1, Masataka Chuzenji*1, Shoichi Kikuchi*4, Masayoshi Mizutani*1,, and Tsunemoto Kuriyagawa*3
*1Graduate School of Engineering, Tohoku University
6-6-01 Aramaki Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan
*2Graduate School of Dentistry, Tohoku University, Sendai, Japan
*3Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan
*4Department of Mechanical Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu, Japan
The reduced density of the autogenous bone around metal medical implants forces joint replacement patients to undergo revision surgery. The loss of bone density is caused by a significant difference in the elastic modulus between implants and autogenous bone. Various studies have attempted to reduce the elastic modulus of the implant to close the large gap in the two moduli. Porous metal is a promising material for reducing the elastic modulus of implants, but it is difficult to fabricate a closed-cell structure like bone using conventional porous metal fabrication methods. In this study, porous Ti-6Al-4V was prepared by selective laser melting, then its porosity was evaluated by X-ray computed tomography. Additionally, tensile test specimens of the porous structure were prepared and the effect of pores on the tensile properties was evaluated. Depending on the energy density, the structure of the porous body was found to form both closed- and open-cell structures. In the tensile specimens that showed the most favorable results, the elastic modulus was reduced by approximately 90%, and the tensile strength exceeded that of the annealed material. This indicates that a metal implant that has a low elastic modulus while maintaining strength can be obtained.
-  World Health Organization, “World Health Report 2000: Health Systems: Improving Performance,” 2000. https://www.who.int/whr/2000/en/whr00_en.pdf [Accessed December 25, 2019]
-  World Health Organization, “World Health Statistics 2018: Monitoring health for the SDGs,” 2018. https://apps.who.int/iris/bitstream/handle/10665/272596/9789241565585-eng.pdf [Accessed December 25, 2019]
-  Ministry of Healthy, Labour and Welfare, “Comprehensive Survey of Living Conditions 2016,” 2016. https://www.mhlw.go.jp/toukei/saikin/hw/k-tyosa/k-tyosa16/dl/05.pdf [Accessed December 25, 2019]
-  H. Noda, H. Iso, H. Toyoshima, C. Date, A. Yamamoto, S. Kikuchi, A. Koizumi, T. Kondo, Y. Watanabe, Y. Wada, Y. Inaba, and A. Tamakoshi, “Walking and Sports Participation and Mortality From Coronary Heart Disease and Stroke,” J. Am. Coll. Cardiol., Vol.46, No.9, pp. 1761-1767, 2005.
-  Ministry of Healthy, Labour and Welfare, “4th NDB Open Data Japan,” 2019. https://www.mhlw.go.jp/content/12400000/000539648.pdf [Accessed December 25, 2019]
-  Y. Noyama, T. Miura, T. Ishimoto, N. Ikeo, M. Niinomi, and T. Nakano, “Bone Loss and Degradation of Bone Quality in the Human Femur after Total Hip Arthroplasty under Stress-Shielding by Titanium-Based Implant,” J. Japan Inst. Metals, Vol.76, No.7, pp. 468-473, 2012.
-  H. Lindahl, “Epidemiology of periprosthetic femur fracture around a total hip arthroplasty,” Injury, Vol.38, pp. 651-654, 2007.
-  C. E. Wen, Y. Yamada, K. Shimojima, Y. Chino, T. Asahina, and M. Mabuchi, “Processing and mechanical properties of autogenous titanium implant materials,” J. Mater. Sci-Mater. M., Vol.13, pp. 397-401, 2002.
-  S. Fujibayashi, M. Neo, H. M. Kim, T. Kokubo, and T. Nakamura, “Osteoinduction of porous bioactive titanium metal,” Biomaterials, Vol.25, No.3, pp. 443-450, 2004.
-  T. Nakamoto, N. Shirakawa, N. Shinomiya, and H. Inui, “Selective Laser Melting of Biomaterial (Pure Titanium) with High-Power Laser,” J. of Japan Society for Laser Surgery and Medicine, Vol.33, No.2, pp. 166-174, 2012.
-  D. A. Hollander, M. V. Walter, T. Wirtz, R. Sellei, B. S. Rohlfing, O. Paar, and H. Erli, “Structural, mechanical and in-vitro characterization of individually structured Ti-6Al-4V produced by direct laser forming,” Biomaterials, Vol.27, No.7, pp. 955-963, 2006.
-  L. J. Gibson and M. F. Ashby, “Cellular Solids: structure and properties,” Pergamon Press, 1988.
-  R. Goodall and A. Mortensen, “Porous Metals,” Physical Metallurgy, pp. 2399-2595, 2014.
-  T. Shibutani, “Evaluation of Crack Initiation at Interfacial Edge on the Basis of Fracture Mechanics Concept and Application to Electronics Devices,” J. JIEP, Vol.7, No.7, pp. 639-644, 2004.
-  A. Simchi and H. Pohl, “Effects of laser sintering processing parameters on the microstructure and densification of iron powder,” Mater. Sci. Eng. A, Vol.359, Nos.1-2, pp. 119-128, 2003.
-  D. Dai, D. Gu, H. Zhang, J. Xiong, C. Ma, C. Hong, and R. Poprawe, “Influence of scan strategy and molten pool configuration on microstructures and tensile properties of selective laser melting additive manufactured aluminum based parts,” Opt. Laser Technol., Vol.99, No.1, pp. 91-100, 2018.
-  H. Gu, H. Gong, D. Pal, K. Rafi, T. J. J. Starr, and B. E. Stucker, “Influences of Energy Density on Porosity and Microstructure of Selective Laser Melted 17-4PH Stainless Steel,” Proc. of Annual Int. Solid Freeform Fabrication Symp., pp. 474-489, 2013.
-  C. Meier, R. W. Penny, Y. Zou, J. S. Gibbs, and A. J. Hart, “Thermophysical Phenomena in Metal Additive Manufacturing by Selective Laser Melting: Fundamentals, Modeling, Simulation and Experimentation,” Annu. Rev. Heat Trans., Vol.20, pp. 241-316, 2018.
-  H. Attar, S. E. Haghighi, D. Kent, X. Wu, and M. S. Dargusch, “Comparative study of commercially pure titanium produced by laser engineered net shaping, selective laser melting and casting processes,” Mater. Sci. Eng. A, Vol.705, pp. 385-393, 2017.
-  Y. Hangai, I. Akuzawa, S. Kitahara, O. Kuwazuru, N. Yoshikawa, and S. Amada, “Influence of Compression Process on Amount and Morphology of Porosity in Aluminum Alloy ADC12 Die-casting Products,” J. JFS, Vol.78, No.11, pp. 551-556, 2006.
-  M. Simonelli, Y. Y. Tse, and C. Tuck, “On the Texture Formation of Selective Laser Melted Ti-6Al-4V,” Metall. Mater. Trans. A, Vol.45, No.6, pp. 2863-2872, 2014.
-  T. Morita, C. Tsuda, H. Sakai, and N. Higuchi, “Fundamental Properties of Ti-6Al-4V Alloy Produced by Selective Laser Melting Method,” Mater. Trans., Vol.58, No.10, pp. 1397-1403, 2017.
-  E. W. Lui, W. Xu, A. Pateras, M. Qian, and M. Brandt, “New Development in Selective Laser Melting of Ti-6Al-4V: A Wider Processing Window for the Achievement of Fully Lamellar α+β Microstructures,” JOM, Vol.69, pp. 2679-2683, 2017.
-  M. Niinomi, “Mechanical properties of biomedical titanium alloys,” Mater. Sci. Eng. A, Vol.243, Nos.1-2, pp. 231-236, 1998.
-  H. Kyogoku and T. Ikeshoji, “A review of metal additive manufacturing technologies: Mechanism of defects formation and simulation of melting and solidification phenomena in laser powder bed fusion process,” Mech. Eng. Rev., Vol.7, No.1, pp. 1-19, 2020.
-  T. Ikeshoji, “Liquidation and Solidification Phenomena During Laser Powder Bed Fusion Process,” J. Smart Process., Vol.6, No.3, pp. 109-114, 2017.
-  J. J. S. Dilip, S. Zhang, C. Teng, K. Zeng, C. Robinson, D. Pal, and B. Stucker, “Influence of processing parameters on the evolution of melt pool, porosity, and microstructures in Ti-6Al-4V alloy parts fabricated by selective laser melting,” Progress in Additive Manufacturing, Vol.2, pp. 157-167, 2017.
-  M. Okayasu, K. Kanazawa, and N. Nishi, “Effects of Internal Defects on Tensile Properties of ADC10 Die Casting,” J. JFS, Vol.70, No.11, pp. 779-785, 1998.
-  T. L. Anderson, “Fracture mechanics: Fundamentals and applications (3rd ed.),” Taylor and Francis, pp. 219-232, 2011.
-  C. Ouchi, “Thermomechanical Processing in Titanium Alloys,” Bulletin of the Japan Inst. of Metals, Vol.25, No.8, pp. 672-679, 1986.
-  T. Vilaro, C. Colin, and J. D. Bartout, “As-Fabricated and Heat-Treated Microstructures of the Ti-6Al-4V Alloy Processed by Selective Laser Melting,” Metall. Mater. Trans. A, Vol.42, No.10, pp. 3190-3199, 2011.
-  H. K. Rafi, J. V. Karthik, H. Gong, T. L. Starr, and B. E. Stucker, “Microstructures and Mechanical Properties of TI6Al4V Parts Fabricated by Selective Laser Melting and Electron Beam Melting,” J. Mater. Eng. Perform., Vol.22, No.12, pp. 3872-3883, 2013.
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