PSI - Issue 79

Saveria Spiller et al. / Procedia Structural Integrity 79 (2026) 176–181

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Fig. 4: results of the EDS analysis performed on the secondary phases observed in the interdendritic areas in the fusion zone.

4. Conclusions The weldability of the AM Ni-based alloy IN625 was investigated through the analysis of a BoP obtained via LBW. The BoP is sound, revealing a minimal presence of defects such as gas porosities. No welding cracks were detected. The fusion zone obtained is characterized by large columnar grains that strongly impact the microhardness profile, resulting in a significant drop in comparison to the microhardness of the parent material, characterized by a fine microstructure. Secondary phases that are thought to be Laves phases and Nb carbides were observed in the interdendritic areas in the fusion zone. The phases are rich in Nb, C, and Mo. Although the present work results in a positive evaluation of the weldability of L-PBF IN625 plates, several other factors shall be taken into account in further studies. For example, L-PBF induces a very specific microstructure, with elongated grains along the building direction, as confirmed by the EBSD analysis carried out. The influence of the grain orientation might possibly affect the weldability of the alloy. For this reason, welding L-PBF plates obtained in different layouts is an interesting study for future development. Moreover, the set of welding parameters adopted must be compared with other combinations to evaluate the feasibility of the process with different values for laser power, welding speed, and power modulation. References AL-Nafeay, R. H., AL-Roubaiy, A. O., & Omidvar, H. (2021). Overview of Joining and Repairing Techniques of Ni-Based Superalloy for Industrial Gas Turbine Applications. IOP Conference Series: Materials Science and Engineering , 1094 (1), 012141. doi: 10.1088/1757 899x/1094/1/012141 Donnini, R., Varone, A., Palombi, A., Spiller, S., Ferro, P., & Angella, G. (2025). High Energy Density Welding of Ni-Based Superalloys: An Overview . Han, J. W., Jung, S. H., Cho, H., & Lee, H. W. (2018). Investigation of the Weld Properties of Inconel 625 based on Nb Content . 13 , 2829–2841. doi: 10.20964/2018.03.01 Henderson, M. B., Arrell, D., Larsson, R., Heobel, M., & Marchant, G. (2004). Nickel based superalloy welding practices for industrial gas turbine applications. Science and Technology of Welding and Joining , 9 (1), 13–21. doi: 10.1179/136217104225017099 Jelokhani-Niaraki, M. R., B. Mostafa Arab, N., Naffakh-Moosavy, H., & Ghoreishi, M. (2016). The systematic parameter optimization in the Nd:YAG laser beam welding of Inconel 625. International Journal of Advanced Manufacturing Technology , 84 (9–12), 2537–2546. doi: 10.1007/s00170-015-7833-4 Li, S., Wei, Q., Shi, Y., Zhu, Z., & Zhang, D. (2015). Microstructure Characteristics of Inconel 625 Superalloy Manufactured by Selective Laser Melting. Journal of Materials Science & Technology , 31 (9), 946–952. doi: 10.1016/j.jmst.2014.09.020 Marchese, B. G., Colera, X. G., Calignano, F., Lorusso, M., Biamino, S., Minetola, P., & Manfredi, D. (2016). Characterization and Comparison of Inconel 625 Processed by Selective Laser Melting and Laser Metal Deposition . Lmd , 1–9. doi: 10.1002/adem.201600635 Newbury, D. E., & Ritchie, N. W. M. (2013). Is scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS) quantitative? Scanning , 35 (3), 141–168. doi: 10.1002/sca.21041 Patterson, T., Hochanadel, J., Sutton, S., Panton, B., & Lippold, J. (2021). A review of high energy density beam processes for welding and additive manufacturing applications. Welding in the World , 65 (7), 1235–1306. doi: 10.1007/s40194-021-01116-0 Qin, L., Chen, C., Zhang, M., & Wang, X. (2017). The microstructure and mechanical properties of deposited-IN625 by laser additive manufacturing Article information: December . doi: 10.1108/RPJ-05-2016-0081 Schnell, A., Hoebel, M., & Samuleson, J. (2011). A study of the weldability of gamma prime hardened superalloys. Advanced Materials Research , 278 , 434–439. doi: 10.4028/www.scientific.net/AMR.278.434 Sekhar, N. C., & Reed, R. C. (2002). Power beam welding of thick section nickel base superalloys. Science and Technology of Welding and