Detection of sub-superficial defects by infrared thermography in parts made by powder bed fusion with electron beam
Silvio DEFANTI, Simone DE GIORGI, Giovanni RIZZA, Giulia COLOMBINI, Emanuele TOGNOLI, Ahmet Ayberk Gürbüz, Lucia DENTI, Manuela Galati, Luca Iuliano
Abstract. This study explores infrared thermography as a cost-effective alternative to computed tomography for detecting subsurface defects in parts produced by powder bed fusion with an electron beam (PBF-EB). Ti6Al4V specimens were produced with designed defects that mimic subsurface pores or discontinuities whose size and depth are typical of PBF-EB. Computed tomography (CT-scan) was used to collect information on the defect dimensions and coordinates accurately. The same samples were therefore analysed using Joule heating infrared thermography, applying electric current while an infrared camera recorded the temperature development on the surface of the sample. The joint analysis of CT scan and thermography data provided a comprehensive study on the limits of the inspection technologies, PBF-EB process, and measuring system in terms of defect size, depth, and the size-to-depth ratio. The results showed that the surface characteristics of the PBF-EB are critical for thermography.
Keywords
Powder Bed Fusion, Thermography, Inspection
Published online 9/10/2025, 9 pages
Copyright © 2025 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Silvio DEFANTI, Simone DE GIORGI, Giovanni RIZZA, Giulia COLOMBINI, Emanuele TOGNOLI, Ahmet Ayberk Gürbüz, Lucia DENTI, Manuela Galati, Luca Iuliano, Detection of sub-superficial defects by infrared thermography in parts made by powder bed fusion with electron beam, Materials Research Proceedings, Vol. 57, pp 38-46, 2025
DOI: https://doi.org/10.21741/9781644903735-5
The article was published as article 5 of the book Italian Manufacturing Association Conference
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
References
[1] ASTM International and ISO/ASTMTR52905, Additive Manufacturing of Metals—Nondestructive Testing and Evaluation—Defect Detection in Parts. ASTM International100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, 2023. https://doi.org/10.1520/ISO/ASTMTR52905-EB
[2] M. Galati, “Electron beam melting process,” in Additive Manufacturing, Elsevier, 2021, pp. 277–301. https://doi.org/10.1016/B978-0-12-818411-0.00014-8
[3] ASTM International and E3166-20, “Standard Guide for Nondestructive Examination of Metal Additively Manufactured Aerospace Parts After Build,” Feb. 01, 2020, ASTM International, West Conshohocken, PA. https://doi.org/10.1520/E3166-20
[4] Y. Zhu, Z. Wu, W. D. Hartley, J. M. Sietins, C. B. Williams, and H. Z. Yu, “Unraveling pore evolution in post-processing of binder jetting materials: X-ray computed tomography, computer vision, and machine learning,” Addit Manuf, vol. 34, p. 101183, Aug. 2020. https://doi.org/10.1016/j.addma.2020.101183
[5] Y. Gui, K. Aoyagi, and A. Chiba, “Development of macro-defect-free PBF-EB-processed Ti–6Al–4V alloys with superior plasticity using PREP-synthesized powder and machine learning-assisted process optimization,” Materials Science and Engineering: A, vol. 864, p. 144595, Feb. 2023. https://doi.org/10.1016/j.msea.2023.144595
[6] Z. Snow, A. R. Nassar, and E. W. Reutzel, “Invited Review Article: Review of the formation and impact of flaws in powder bed fusion additive manufacturing,” Addit Manuf, vol. 36, p. 101457, Dec. 2020. https://doi.org/10.1016/j.addma.2020.101457
[7] T. Liu, S. Guessasma, J. Zhu, W. Zhang, H. Nouri, and S. Belhabib, “Microstructural defects induced by stereolithography and related compressive behaviour of polymers,” J Mater Process Technol, vol. 251, pp. 37–46, Jan. 2018. https://doi.org/10.1016/j.jmatprotec.2017.08.014
[8] P. Charalampous, I. Kostavelis, and D. Tzovaras, “Non-destructive quality control methods in additive manufacturing: a survey,” Rapid Prototyp J, vol. 26, no. 4, pp. 777–790, Mar. 2020. https://doi.org/10.1108/RPJ-08-2019-0224
[9] X. Yang, Y. Li, and B. Li, “Formation mechanisms of lack of fusion and keyhole-induced pore defects in laser powder bed fusion process: A numerical study,” International Journal of Thermal Sciences, vol. 188, p. 108221, Jun. 2023. https://doi.org/10.1016/j.ijthermalsci.2023.108221
[10] C. Du et al., “Pore defects in Laser Powder Bed Fusion: Formation mechanism, control method, and perspectives,” J Alloys Compd, vol. 944, p. 169215, May 2023. https://doi.org/10.1016/j.jallcom.2023.169215
[11] M. S. Palm, B. Diepold, S. Neumeier, H. W. Hoeppel, M. Goeken, and M. F. Zaeh, “Detection and effects of lack of fusion defects in Hastelloy X manufactured by laser powder bed fusion,” Mater Des, vol. 230, p. 111941, Jun. 2023. https://doi.org/10.1016/j.matdes.2023.111941
[12] R. Zhao, A. Shmatok, R. Fischer, and B. C. Prorok, “Investigation of Causal Relationships between Printing Parameters, Pore Properties and Porosity in Laser Powder Bed Fusion,” Metals (Basel), vol. 13, no. 2, p. 330, Feb. 2023. https://doi.org/10.3390/met13020330
[13] W. Wang et al., “Processing defect, microstructure evolution and mechanical properties of laser powder bed fusion Al-12Si alloys,” Journal of Materials Research and Technology, vol. 26, pp. 681–696, Sep. 2023. https://doi.org/10.1016/j.jmrt.2023.07.231
[14] N. Kouraytem et al., “Solidification crack propagation and morphology dependence on processing parameters in AA6061 from ultra-high-speed x-ray visualization,” Addit Manuf, vol. 42, p. 101959, Jun. 2021. https://doi.org/10.1016/j.addma.2021.101959
[15] R. Yang and Y. He, “Optically and non-optically excited thermography for composites: A review,” Infrared Phys Technol, vol. 75, pp. 26–50, Mar. 2016. https://doi.org/10.1016/j.infrared.2015.12.026
[16] B. Wiecek, “Review on thermal image processing for passive and active thermography,” in 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference, IEEE, 2005, pp. 686–689. doi: 10.1109/IEMBS.2005.1616506
[17] C. Meola, S. Boccardi, and G. M. Carlomagno, Infrared Thermography in the Evaluation of Aerospace Composite Materials. Elsevier, 2015
[18] A. Heifetz, X. Zhang, J. Saniie, and W. Cleary, “Detection of Defects in Additively Manufactured Metallic Materials with Machine Learning of Pulsed Thermography Images,” Argonne, IL (United States), Sep. 2020. doi: 10.2172/1673390
[19] N. Montinaro, D. Cerniglia, and G. Pitarresi, “Defect detection in additively manufactured titanium prosthesis by flying laser scanning thermography,” Procedia Structural Integrity, vol. 12, pp. 165–172, 2018. https://doi.org/10.1016/j.prostr.2018.11.098
[20] E. D’Accardi, S. Altenburg, C. Maierhofer, D. Palumbo, and U. Galietti, “Detection of Typical Metal Additive Manufacturing Defects by the Application of Thermographic Techniques,” in The 15th International Workshop on Advanced Infrared Technology and Applications, Basel Switzerland: MDPI, Sep. 2019, p. 24. doi: 10.3390/proceedings2019027024
[21] C. G. Kolb et al., “An investigation on the suitability of modern nondestructive testing methods for the inspection of specimens manufactured by laser powder bed fusion,” SN Appl Sci, vol. 3, no. 7, p. 713, Jul. 2021. https://doi.org/10.1007/s42452-021-04685-3
[22] M. Galati and S. Defanti, “Additive Manufacturing of Locally Weakened Parts to Obtain a Designed Fracture,” Metals and Materials International, vol. 30, no. 2, 2024. https://doi.org/10.1007/s12540-023-01506-7
[23] F. J. Madruga, C. Ibarra-Castanedo, O. M. Conde, J. M. López-Higuera, and X. Maldague, “Infrared thermography processing based on higher-order statistics,” NDT & E International, vol. 43, no. 8, pp. 661–666, Nov. 2010. https://doi.org/10.1016/j.ndteint.2010.07.002
[24] R. Usamentiaga, C. Ibarra-Castanedo, and X. Maldague, “More than Fifty Shades of Grey: Quantitative Characterization of Defects and Interpretation Using SNR and CNR,” J Nondestr Eval, vol. 37, no. 2, p. 25, Jun. 2018. https://doi.org/10.1007/s10921-018-0479-z
