Ahmet Murat DURSUN, Mehmet Çağrı TÜZEMEN, Elmas SALAMCI, Oğuzhan YILMAZ, Rahmi ÜNAL

İşlevsel Geçişli Gözenekli Yapıların Tasarımı ve Eklemeli Üretilen Parçalar Arasındaki Uyumluluğun Araştırılması

Bu çalışmada, Ti-6Al-4V geçişli gözenekli yapıların üç farklı birim hücre yapısı için gözeneklilik oranlarındaki sapmalar araştırılmıştır. Bu amaçla, işlevsel geçişli hücresel yapılar tasarlanmış ve seçici lazer ergitme yöntemiyle üretilmiştir. Ayrıca birim hücre yapısının, birim hücre boyutunun ve kolon (dikme) kalınlığının gözenek boyutlarındaki sapma seviyesi üzerindeki etkilerinin araştırılması amaçlanmıştır. Numuneler, üretim sonrası yapı boyutunu belirlemek için mikro bilgisayarlı tomografide (mikro-BT) taranmıştır. Mikro-BT'den elde edilen sonuçlara göre, geçişli gözenekli tüm hücre yapılarının kolon kalınlık değerlerinde ortalama 150-300 μm arasında değişen artışlar gözlenmiştir. Kübik ve sekizyüzlü yapıların yatay kolonlarında üretim sırasında ergiyen metal sebebiyle sarkmalar oluştuğu gözlenmiştir. Üretilen parçaların gözenekliliği, tasarım değerleri ile karşılaştırıldığında kübik yapıda %5.71-%10.54, sekizyüzlü yapıda %8.59-12.39 ve elmas yapıda %13-16.49 aralıklarında değişen oranlarda sapmaların oluştuğu tespit edilmiştir.

Anahtar Kelimeler:

Eklemeli üretim, gözeneklilik, işlevsel basamaklandırılmış yapı, mikro-BT

Investigation of Compatibility Between Design and Additively Manufactured Parts of Functionally Graded Porous Structures

In this study, deviations for the porosity level of the Ti-6Al-4V functionally graded porous structures for three different cell structures were investigated. For this purpose, functionally graded porous structures are designed and produced by selective laser melting (SLM). It is also aimed to investigate the effects of unit cell structure, unit cell size, and column (strut) thickness on the porosity deviation level. The specimens were scanned at micro-computed tomography (micro-CT) to determine the structure dimensions after production. According to the results obtained from micro-CT, an average increase of 150-300 μm was observed on the column thicknesses of all functionally graded porous structures. It has been observed that the horizontal columns of cubic and octagonal structures have sagging due to metal melting during production. It has been determined that the porosity of the manufactured parts was deviated between 5.71%-10.54% for cubic, 8.59%-12.39% for octahedroid, and 13%-16.49% for diamond structures compared to the design values.

Keywords:

Additive manufacturing, porosity, functionally graded structure, micro-CT,

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[1] Zhang X. Y., Fang G., Leeflang S., Zadpoor A. A., and Zhou J., "Topological design, permeability and mechanical behavior of additively manufactured functionally graded porous metallic biomaterials", Acta Biomaterialia, 84: 437–452, (2019).
[2] Zhang X. Y., Yan X. C., Fang G., and Liu M., "Biomechanical influence of structural variation strategies on functionally graded scaffolds constructed with triply periodic minimal surface", Additive Manufacturing, 32: 101015, (2020).
[3] Zhao D., Huang Y., Ao Y., Han C., Wang Q., Li Y., Liu J., Wei Q., and Zhang Z., "Effect of pore geometry on the fatigue properties and cell affinity of porous titanium scaffolds fabricated by selective laser melting", Journal of the Mechanical Behavior of Biomedical Materials, 88: 478–487, (2018).
[4] Dallago M., Fontanari V., Winiarski B., Zanini F., Carmignato S., and Benedetti M., "Fatigue properties of Ti6Al4V cellular specimens fabricated via SLM: CAD vs real geometry", Procedia Structural Integrity, 7: 116–123, (2017).
[5] Ali H., Ghadbeigi H., and Mumtaz K., "Processing Parameter Effects on Residual Stress and Mechanical Properties of Selective Laser Melted Ti6Al4V", Journal of Materials Engineering and Performance, 27: 4059–4068, (2018).
[6] Aydın İ., and Engin F., "Hydroxyapatite Coating on Ti6Al4V Alloy Surface Through Biomimetic Method Using Glycolic Acid - Sodium Gluconate Buffer System and Examination of Properties of the Coating", Journal of Polytechnic, 20: 993–1001, (2017).
[7] Subaşi M., Safarian A., and Karataş Ç., "An Investigation of Sintering Parameters of Ti-6Al-7Nb Fabricated by Powder Injection Molding", Journal of Polytechnic, 30: 502–512, (2017).
[8] Subasi O., Oral A., and Lazoglu I., "A novel adjustable locking plate (ALP) for segmental bone fracture treatment", Injury, 50: 1612–1619, (2019).
[9] Wu L., and Zhang J., "Phase Field Simulation of Dendritic Solidification of Ti-6Al-4V During Additive Manufacturing Process", Jom, 70: 2392–2399, (2018).
[10] Challis V. J., Xu X., Zhang L. C., Roberts A. P., Grotowski J. F., and Sercombe T. B., "High specific strength and stiffness structures produced using selective laser melting", Materials and Design, 63: 783–788, (2014).
[11] Gibson L. J., and Ashby M. F., Cellular solids: Structure and properties, second edition. Cell Solids Struct Prop Second Ed.
[12] Mazur M., Leary M., McMillan M., Sun S., Shidid D., and Brandt M., "Mechanical properties of Ti6Al4V and AlSi12Mg lattice structures manufactured by Selective Laser Melting (SLM)", Laser Additive Manufacturing: Materials, Design, Technologies, and Applications, 119–161, (2017).
[13] Arabnejad S., Burnett Johnston R., Pura J. A., Singh B., Tanzer M., and Pasini D., "High-strength porous biomaterials for bone replacement: A strategy to assess the interplay between cell morphology, mechanical properties, bone ingrowth and manufacturing constraints", Acta Biomaterialia, 30: 345–356, (2016).
[14] Zhang S., Wei Q., Cheng L., Li S., and Shi Y., "Effects of scan line spacing on pore characteristics and mechanical properties of porous Ti6Al4V implants fabricated by selective laser melting", Materials and Design, 63: 185–193, (2014).
[15] Tsai P. I., Hsu C. C., Chen S. Y., Wu T. H., and Huang C. C., "Biomechanical investigation into the structural design of porous additive manufactured cages using numerical and experimental approaches", Computers in Biology and Medicine, 76: 14–23, (2016).
[16] Sing S. L., Yeong W. Y., Wiria F. E., and Tay B. Y., "Characterization of Titanium Lattice Structures Fabricated by Selective Laser Melting Using an Adapted Compressive Test Method", Experimental Mechanics, 56: 735–748, (2016).
[17] Van Bael S., Kerckhofs G., Moesen M., Pyka G., Schrooten J., and Kruth J. P., "Micro-CT-based improvement of geometrical and mechanical controllability of selective laser melted Ti6Al4V porous structures", Materials Science and Engineering A, 528: 7423–7431, (2011).
[18] Xu Y., Zhang D., Zhou Y., Wang W., and Cao X., "Study on topology optimization design, manufacturability, and performance evaluation of Ti-6Al-4V porous structures fabricated by selective laser melting (SLM)", Materials, 10 (9): 1048, (2017).
[19] Balcı A., Küçükaltun F., Aycan M. F., Usta Y., and Demir T., "Reproducibility of Replicated Trabecular Bone Structures from Ti6Al4V Extralow Interstitials Powder by Selective Laser Melting", Arabian Journal for Science and Engineering, 46: 2527–2541, (2021).
[20] Balcı A., Aycan M. F., Usta Y., and Demir T., "Seçimli Lazer Ergitme İle Ti6Al4V ELI Alaşımından Üretilen Trabeküler Metal Yapıların Basma Ve Basma-Kayma Dayanımlarının İncelenmesi", Journal of Polytechnic, 1–1, (2020).
[21] Mullen L., Stamp R. C., Brooks W. K., Jones E., and Sutcliffe C. J., "Selective laser melting: A regular unit cell approach for the manufacture of porous, titanium, bone in-growth constructs, suitable for orthopedic applications", Journal of Biomedical Materials Research - Part B Applied Biomaterials, 89: 325–334, (2009).
[22] Bai Y., Wang D., Yang Y., and Wang H., "Effect of heat treatment on the microstructure and mechanical properties of maraging steel by selective laser melting", Materials Science and Engineering A, 760: 105–117, (2019).
[23] Li S. J., Xu Q. S., Wang Z., Hou W. T., Hao Y. L., Yang R., and Murr L. E., "Influence of cell shape on mechanical properties of Ti-6Al-4V meshes fabricated by electron beam melting method", Acta Biomaterialia, 10: 4537–4547, (2014).
[24] Van Bael S., Chai Y. C., Truscello S., Moesen M., Kerckhofs G., Van Oosterwyck H., Kruth J. P., and Schrooten J., "The effect of pore geometry on the in vitro biological behavior of human periosteum-derived cells seeded on selective laser-melted Ti6Al4V bone scaffolds", Acta Biomaterialia, 8: 2824–2834, (2012).
[25] Warnke P. H., Douglas T., Wollny P., Sherry E., Steiner M., Galonska S., Becker S. T., Springer I. N., Wiltfang J., and Sivananthan S., "Rapid prototyping: Porous titanium alloy scaffolds produced by selective laser melting for bone tissue engineering", Tissue Engineering - Part C: Methods, 15: 115–124, (2009).
[26] Han C., Li Y., Wang Q., Wen S., Wei Q., Yan C., Hao L., Liu J., and Shi Y., "Continuous functionally graded porous titanium scaffolds manufactured by selective laser melting for bone implants", Journal of the Mechanical Behavior of Biomedical Materials, 80: 119–127, (2018).
[27] Emmelmann C., Scheinemann P., Munsch M., and Seyda V., "Laser additive manufacturing of modified implant surfaces with osseointegrative characteristics", Physics Procedia, 12: 375–384, (2011).
[28] Parthasarathy J., Starly B., Raman S., and Christensen A., "Mechanical evaluation of porous titanium (Ti6Al4V) structures with electron beam melting (EBM)", Journal of the Mechanical Behavior of Biomedical Materials, 3: 249–259, (2010).
[29] Bagheri Z. S., Melancon D., Liu L., Johnston R. B., and Pasini D., "Compensation strategy to reduce geometry and mechanics mismatches in porous biomaterials built with Selective Laser Melting", Journal of the Mechanical Behavior of Biomedical Materials, 70: 17–27, (2017).
[30] Weißmann V., Wieding J., Hansmann H., Laufer N., Wolf A., and Bader R., "Specific yielding of selective laser-melted Ti6Al4V open-porous scaffolds as a function of unit cell design and dimensions", Metals, 6 (7): 166, (2016).
[31] Nune K. C., Kumar A., Misra R. D. K., Li S. J., Hao Y. L., and Yang R., "Osteoblast functions in functionally graded Ti-6Al-4 v mesh structures", Journal of Biomaterials Applications, 30: 1182–1204, (2016).
[32] Shi J., Yang J., Li Z., Zhu L., Li L., and Wang X., "Design and fabrication of graduated porous Ti-based alloy implants for biomedical applications", Journal of Alloys and Compounds, 728: 1043–1048, (2017).
[33] ASTM F 136-02A, "Standard specification for wrought titanium-6aluminum-4vanadium eli (extra low interstitial) alloy for surgical implant applications", (2002).
[34] Spierings A. B., Schneider M., and Eggenberger R., "Comparison of density measurement techniques for additive manufactured metallic parts", Rapid Prototyping Journal, 17: 380–386, (2011).
[35] Romano S., Abel A., Gumpinger J., Brandão A. D., and Beretta S., "Quality control of AlSi10Mg produced by SLM: Metallography versus CT scans for critical defect size assessment", Additive Manufacturing, 28: 394–405, (2019).
[36] Pyka G., Kerckhofs G., Schrooten J., and Wevers M., "The effect of spatial micro-CT image resolution and surface complexity on the morphological 3D analysis of open porous structures", Materials Characterization, 87: 104–115, (2014).
[37] Gong H., Nadimpalli V. K., Rafi K., Starr T., and Stucker B., "Micro-CT Evaluation of Defects in Ti-6Al-4V Parts Fabricated by Metal Additive Manufacturing", Technologies, 7: 44, (2019).
[38] Zhou X., Dai N., Chu M., Wang L., Li D., Zhou L., and Cheng X., "X-ray CT analysis of the influence of process on defect in Ti-6Al-4V parts produced with Selective Laser Melting technology", The International Journal of Advanced Manufacturing Technology, 106 (1): 3-14, (2020).
[39] Liu Y., Li X., Chen C., Song Y., and Ni P., "High throughput rapid detection for SLM manufactured elements using ultrasonic measurement", Measurement: Journal of the International Measurement Confederation, 144: 234–242, (2019).
[40] Wang X., Xu S., Zhou S., Xu W., Leary M., Choong P., Qian M., Brandt M., and Xie Y. M., "Topological design and additive manufacturing of porous metals for bone scaffolds and orthopaedic implants: A review", Biomaterials, 83: 127–141, (2016).
[41] Wang D., Wu S., Fu F., Mai S., Yang Y., Liu Y., and Song C., "Mechanisms and characteristics of spatter generation in SLM processing and its effect on the properties", Materials and Design, 137: 33–37, (2018).