Microstructural Development and Mechanical Properties of Selective Laser Melted Co–Cr–W Dental Alloy
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Dental restorations are a predestined area for additive manufacturing, due to the required fast fabrication, the low quantities, and the freedom in geometrical designs. Past studies revealed that there is a significant difference in the microstructure compared to traditional investment cast restorations, with drastic implications on the material properties. In many instances, these changes are beneficial, i.e. higher mechanical strength and increased ductility, but at a reduced elastic stiffness. The latter is crucial for the type 5 classification and, based on the studies on a selective laser melted Co–Cr–W dental alloy, a post-heat treatment is inevitable to safely exceed the 150 GPa minimum requirement. Heat treatment at 1150 °C caused a recrystallization and a formation of tungsten rich precipitates, surrounded by a tungsten depleted cobalt–chromium matrix. In the heat-treated state, the alloy exhibited semi-isotropic tensile properties with an average Young’s modulus of about 200 GPa, safely meeting the dental type 2 to 5 classifications.
KeywordsPrecipitations Recrystallization Elastic stiffness Tensile properties Dental application
Sincere appreciation to Dr. Frank Alifui-Segbaya for the ongoing collaboration on the metal printing of dental restorations. Moreover, the authors would like to thank Objective 3D (Australia) for kindly supplying the samples for this study.
We gratefully acknowledge the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—280883331 (grant numbers: SCHM 1182/19-2, KR 3687/3-1).
- 1.Alifui-Segbaya F, Evans J, Eggbeer D, George R (2014) Clinical relevance of laser-sintered Co–Cr alloys for prosthodontic treatments: a review. In: Proceedings of the 1st international conference on progress in additive manufacturing, pp 115–120. https://doi.org/10.3850/978-981-09-0446-3_024
- 2.Faure SP, Mercier L, Didier P, Roux R, Coulon JF, Garel S, Trenit J, Buard H, Razan F (2012) Laser sintering process analysis: application to chromium–cobalt alloys for dental prosthesis production. In: ASME 2012 11th biennial conference on engineering systems design and analysis, ESDA 2012, vol 4, pp 9–15Google Scholar
- 4.Hitzler L, Merkel M, Hall W, Öchsner A (2018) A review of metal fabricated with laser- and powder-bed based additive manufacturing techniques: process, nomenclature, materials, achievable properties, and its utilization in the medical sector. Adv Eng Mater 20:1700658. https://doi.org/10.1002/adem.201700658CrossRefGoogle Scholar
- 5.L Hitzler, P Williams, M Merkel, W Hall, A Öchsner (2017) Correlation between the energy input and the microstructure of additively manufactured cobalt–chromium. Defect Diffus Forum 379:157–165. https://doi.org/10.4028/www.scientific.net/DDF.379.157
- 6.Kajima Y, Takaichi A, Kittikundecha N, Nakamoto T, Kimura T, Nomura N, Kawasaki A, Hanawa T, Takahashi H, Wakabayashi N (2018) Effect of heat-treatment temperature on microstructures and mechanical properties of Co–Cr–Mo alloys fabricated by selective laser melting. Mater Sci Eng, A 726:21–31. https://doi.org/10.1016/j.msea.2018.04.048CrossRefGoogle Scholar
- 7.Takaichi A, Suyalatu T Nakamoto, Joko N, Nomura N, Tsutsumi Y, Migita S, Doi H, Kurosu S, Chiba A, Wakabayashi N, Igarashi Y, Hanawa T (2013) Microstructures and mechanical properties of Co–29Cr–6Mo alloy fabricated by selective laser melting process for dental applications. J Mech Behav Biomed Mater 21:67–76. https://doi.org/10.1016/j.jmbbm.2013.01.021CrossRefGoogle Scholar
- 9.British Standards Institution (2016) BS EN ISO 22674—Dentistry: metallic materials for fixed and removable restorations and appliances, London, United KingdomGoogle Scholar
- 10.Hitzler L, Alifui-Segbaya F, Williams P, Merkel M, Heine B, Heitzmann M, Hall W, Öchsner A (2018) Additive manufacturing of cobalt-based dental alloys: analysis of microstructure and physicomechanical properties. Adv Mater Sci Eng 2018:8213023. https://doi.org/10.1155/2018/8213023CrossRefGoogle Scholar
- 11.Concept-Laser, Technical data in line with DIN EN ISO 9693/DIN EN ISO 22674 after recommended heat treatment. https://www.concept-laser.de/fileadmin//user_upload/Datasheet_remanium_star_CL.pdf. Accessed 22 Aug 2019
- 12.Schneider CA, Rasband WS, Eliceiri KW (2012) NIH image to ImageJ: 25 years of image analysis. Nat Methods 9:67–675. http://www.ncbi.nlm.nih.gov/pubmed/5554542. Accessed 14 May 2014