PSI - Issue 41

Saveria Spiller et al. / Procedia Structural Integrity 41 (2022) 158–174 Saveria Spiller/ Structural Integrity Procedia 00 (2019) 000–000

172

15

Other metals were printed with the MEAM technique. For example, Dehdari Ebrahimi et al. (2018) used a copper-binder filament to carry on a study on the conductivity of copper samples obtained by extrusion. MEAM has the potential to produce conductive components with complex and customized geometries for thermal or electrical applications. The thermal conductivity is highly dependent on the porosity of the material, therefore the presence of large voids in the MEAM parts needs to be avoided by optimizing the printing parameters and the sintering process. Tungsten-heavy alloys were printed by Bose et al. (2018). Near fully-dense components were obtained, with a finer microstructure compared to conventionally manufactured samples. The main advantage pointed out in the research is the freedom in the achievable geometrical complexity. Metal-ceramic composites are another category of interest for engineering purposes, since these materials couple the characteristic of metals such as strength and ductility, to the characteristics of ceramics like thermal insulation. Ceramics and metal-ceramic composites are expensive materials, difficult to manufacture. Lengauer et al. (2019) printed both hardmetals (tungsten carbide) and cermet components. The feasibility of the MEAM technique for those materials was demonstrated, but further investigation is needed. The reduction of the porosity should be the main concern to improve the mechanical properties of the sample by properly optimizing the process parameters. A similar study was carried out by Abel et al. (2019). In this study bi-material components were obtained using yttria stabilized Zirconia and 17-4 PH SS. These materials are suitable to be coupled since they present a similar shrinkage behavior and thermal coefficient, meaning that the co-sintering process can be successful. 7. Conclusion Metal Extrusion Additive manufacturing (MEAM) is a promising technique to produce metallic components. Due to the simplicity of the printing process, it is cost-effective and fast compared to other AM and conventional technologies. The post-process described in the previous section is complicated compared to the printing phase since debinding step is required and the sintering is commonly performed under a controlled atmosphere. The post process is the most time and cost-consuming part of the process and further research can be done to simplify it. Nevertheless, the main drawback of the technique regards the final porosity. After the sintering, the silver part often doesn’t reach full density, and the size and distribution of pores were proven to be the roots of the poor mechanical properties of the components. With proper optimization of the parameters, the mechanical properties achieved were reported to be comparable with other techniques such as MIM. The mechanical strength reachable with powder bed fusion technologies significantly the strength of MEAM parts, but the equiaxic and isotropic microstructure increase the ductility and the fracture resistance of the MEAM parts. Further studies are required to obtain fully dense functional components via MEAM and to evaluate the underlying mechanisms of failure in these parts under extreme loading conditions such as cyclic loading where the presence of surface and internal defects is significantly detrimental. References Abel, J., Scheithauer, U., Janics, T., Hampel, S., Cano, S., Müller-Köhn, A., Günther, A., Kukla, C., & Moritz, T. (2019). Fused filament fabrication (FFF) of metal-ceramic components. Journal of Visualized Experiments , 2019 (143). doi: 10.3791/57693 Agarwala, M. K., Weeren, R. Van, Bandyopadhyay, A., Safari, A., Danforth, S. C., & Priedeman, W. R. (1996). Filament Feed Materials for Fused Deposition Processing of Ceramics and Metals. Proceedings Ofthe Solid Freeform Fabrication Symposium , 451–458. Retrieved from http://hdl.handle.net/2152/70277 Alkindi, T., Alyammahi, M., Susantyoko, R. A., & Atatreh, S. (2021). The effect of varying specimens’ printing angles to the bed surface on the tensile strength of 3D-printed 17-4PH stainless-steels via metal FFF additive manufacturing. MRS Communications , 11 (3), 310–316. doi: 10.1557/s43579-021-00040-0 Antonio Travieso-Rodriguez, J., Zandi, M. D., Jerez-Mesa, R., & Lluma-Fuentes, J. (2020). Fatigue behavior of PLA-wood composite manufactured by fused filament fabrication. Journal of Materials Research and Technology , 9 (4), 8507–8516. doi: 10.1016/j.jmrt.2020.06.003 BASF Ultrafuse 316L . (n.d.). Retrieved from https://www.ultrafusefff.com/product-category/metal/ultrafuse-316l/ Benedetti, M., du Plessis, A., Ritchie, R. O., Dallago, M., Razavi, S. M. J., & Berto, F. (2021). Architected cellular materials: A review on their mechanical properties towards fatigue-tolerant design and fabrication. Materials Science and Engineering R: Reports , 144 , 100606. doi: 10.1016/j.mser.2021.100606 Bose, A., Schuh, C. A., Tobia, J. C., Tuncer, N., Mykulowycz, N. M., Preston, A., Barbati, A. C., Kernan, B., Gibson, M. A., Krause, D., Brzezinski, T., Schroers, J., Fulop, R., Myerberg, J. S., Sowerbutts, M., Chiang, Y. M., John Hart, A., Sachs, E. M., Lomeli, E. E., & Lund, A. C. (2018). Traditional and additive manufacturing of a new Tungsten heavy alloy alternative. International Journal of Refractory Metals and Hard Materials , 73 (December 2017), 22–28. doi: 10.1016/j.ijrmhm.2018.01.019