Additive Manufacturing

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Additive manufacturing, also known as 3D printing, is a bottom-up approach in which a part is manufactured layer by layer from a 3D computer model. In the SMAM group, we study the influence of the processing parameters on the microstructural evolution during the printing process. This is achieved by fast operando X-ray diffraction, radiography and small-angle scattering, combined with state-of-the-art post-processing characterisation techniques. 

Laser powder bed fusion is a very complex technique, with many variables. To ensure an optimal build quality, in situ process monitoring is crucial. In a SNF funded Sinergia project, the SMAM group, in collaboration with research groups from EPFL, EMPA and PSI  aim to develop an online monitoring strategy for additive manufacturing. 

Laser powder-bed fusion (LPBF) is the most widely used additive manufacturing process for monolithic metal parts. Many applications would greatly profit if more then one materials could be co-processed in the powder bed. Besides offering a much wider design space, multi-material LPBF would allow for producing functional parts without joining and assembly operations, and add 'function for free' as a new dimension to LPBF. In this project, we explore laser exposure strategies that allow controlled 3D printing of multi-material.

Laser powder bed fusion has great potential to design advanced alloys in situ during the printing process. We explore by operando X-ray diffraction the phase evolution during 3D printing of powder mixtures.

  • Navarre C, Hearn W, Van der Meer M, Schlenger L, Vaerenberg R, Mari N, et al.
    Exploring real-time monitoring of laser-induced recrystallization using acoustic emissions
    Optics and Laser Technology. 2026; 195: 114591 (11 pp.). https://doi.org/10.1016/j.optlastec.2025.114591
    DORA PSI
  • Karra VSSA, Lamprinakos N, Chen Y, Guss G, Rack A, Van Petegem S, et al.
    Solidification cracking of laser melted commercial-purity tungsten
    Scientific Reports. 2025; 15: 42578 (17 pp.). https://doi.org/10.1038/s41598-025-24742-w
    DORA PSI
  • Hearn W, Goel S, Pauzon C, Shaikh AS, Casati N, Hryha E, et al.
    Phase transformations in hypo-eutectoid carbon steel during laser powder bed fusion
    Additive Manufacturing. 2025; 113: 105020 (14 pp.). https://doi.org/10.1016/j.addma.2025.105020
    DORA PSI
  • Markovic P, Scheel P, Wrobel R, Van Petegem S, Leinenbach C, Mazza E, et al.
    High-fidelity thermomechanical simulation of laser powder bed fusion process: impact of constitutive model choice
    Additive Manufacturing Letters. 2025; 51: 100324 (10 pp.). https://doi.org/10.1016/j.addlet.2025.100324
    DORA PSI
  • Özsoy A, Gaudez S, Hearn WA, Baganis A, Hegedüs Z, Chen Y, et al.
    Phase-separation-driven cracking in additive manufacturing of Ni-Cu alloy systems
    Additive Manufacturing. 2025; 110: 104950 (14 pp.). https://doi.org/10.1016/j.addma.2025.104950
    DORA PSI
  • Sofras C, Čapek J, Soundarapandiyan G, Baganis A, Özsoy A, Šmíd M, et al.
    Solidification pathway induced microstructural differences in austenitic stainless steels produced by L-PBF
    Materials Research Letters. 2025; 13(9): 928-935. https://doi.org/10.1080/21663831.2025.2536044
    DORA PSI
  • Özsoy A, Hearn WA, Gaudez S, Jeswani R, Chen Y, Rack A, et al.
    Deconvoluting cracking mechanisms in fusion processing of steel-copper multi-materials via Operando X-ray characterisation
    Virtual and Physical Prototyping. 2025; 20(1): e2526798 (27 pp.). https://doi.org/10.1080/17452759.2025.2526798
    DORA PSI
  • Jamili AM, Basu I, Cayron C, Van Petegem S, Jhabvala J, Grundy AN, et al.
    Formation mechanism and microstructural characteristics of a body-centered cubic phase in 3D printed 316L–CuCrZr multi-material structures, combining laser powder bed fusion with foils
    Scripta Materialia. 2025; 268: 116844 (7 pp.). https://doi.org/10.1016/j.scriptamat.2025.116844
    DORA PSI
  • Jamili AM, Jhabvala J, Van Petegem S, Weisz-Patrault D, Boillat E, Nohava J, et al.
    Avoiding cracks in multi-material printing by combining laser powder bed fusion with metallic foils: application to Ti6Al4V-AlSi12 structures
    Additive Manufacturing. 2025; 97: 104615 (18 pp.). https://doi.org/10.1016/j.addma.2024.104615
    DORA PSI
  • Esmaeilzadeh R, Pandiyan V, Van Petegem S, Van der Meer M, Nasab MH, de Formanoir C, et al.
    Acoustic emission signature of martensitic transformation in laser powder bed fusion of Ti6Al4V-Fe, supported by operando X-ray diffraction
    Additive Manufacturing. 2024; 96: 104562 (18 pp.). https://doi.org/10.1016/j.addma.2024.104562
    DORA PSI
  • Yang J, Schlenger LM, Nasab MH, Van Petegem S, Marone F, Logé RE, et al.
    Experimental quantification of inward Marangoni convection and its impact on keyhole threshold in laser powder bed fusion of stainless steel
    Additive Manufacturing. 2024; 84: 104092 (11 pp.). https://doi.org/10.1016/j.addma.2024.104092
    DORA PSI
  • Navarre C, Van Petegem S, Schlenger L, Cayron C, Hamidi-Nasab M, Esmaeilzadeh R, et al.
    Monitoring of laser-induced fast recrystallization in SS-316L through synchrotron X-ray diffraction
    Materials and Design. 2024; 238: 112628 (14 pp.). https://doi.org/10.1016/j.matdes.2023.112628
    DORA PSI
  • de Formanoir C, Hamidi Nasab M, Schlenger L, Van Petegem S, Masinelli G, Marone F, et al.
    Healing of keyhole porosity by means of defocused laser beam remelting: Operando observation by X-ray imaging and acoustic emission-based detection
    Additive Manufacturing. 2024; 79: 103880 (18 pp.). https://doi.org/10.1016/j.addma.2023.103880
    DORA PSI
  • Esmaeilzadeh R, Hamidi-Nasab M, de Formanoir C, Schlenger L, Van Petegem S, Navarre C, et al.
    In-situ selective laser heat treatment for microstructural control of additively manufactured Ti-6Al-4V
    Additive Manufacturing. 2023; 78: 103882 (14 pp.). https://doi.org/10.1016/j.addma.2023.103882
    DORA PSI
  • Hamidi Nasab M, Masinelli G, de Formanoir C, Schlenger L, Van Petegem S, Esmaeilzadeh R, et al.
    Harmonizing sound and light: X-ray imaging unveils acoustic signatures of stochastic inter-regime instabilities during laser melting
    Nature Communications. 2023; 14: 8008 (14 pp.). https://doi.org/10.1038/s41467-023-43371-3
    DORA PSI
  • Gao S, Li Z, Van Petegem S, Ge J, Goel S, Vas JV, et al.
    Additive manufacturing of alloys with programmable microstructure and properties
    Nature Communications. 2023; 14(1): 6752 (11 pp.). https://doi.org/10.1038/s41467-023-42326-y
    DORA PSI
  • Gh Ghanbari P, Markovic P, Van Petegem S, Makowska MG, Wrobel R, Mayer T, et al.
    A close look at temperature profiles during laser powder bed fusion using operando X-ray diffraction and finite element simulations
    Additive Manufacturing Letters. 2023; 6: 100150 (9 pp.). https://doi.org/10.1016/j.addlet.2023.100150
    DORA PSI
  • König H-H, Holländer Pettersson N, Durga A, Van Petegem S, Grolimund D, Chuang AC, et al.
    Solidification modes during additive manufacturing of steel revealed by high-speed X-ray diffraction
    Acta Materialia. 2023; 246: 118713 (11 pp.). https://doi.org/10.1016/j.actamat.2023.118713
    DORA PSI
  • Chen M, Van Petegem S, Zou Z, Simonelli M, Tse YY, Chang CST, et al.
    Microstructural engineering of a dual-phase Ti-Al-V-Fe alloy via in situ alloying during laser powder bed fusion
    Additive Manufacturing. 2022; 59: 103173 (10 pp.). https://doi.org/10.1016/j.addma.2022.103173
    DORA PSI
  • Chen M, Simonelli M, Van Petegem S, Tse YY, Chang CST, Makowska MG, et al.
    A quantitative study of thermal cycling along the build direction of Ti-6Al-4V produced by laser powder bed fusion
    Materials and Design. 2023; 225: 111458 (11 pp.). https://doi.org/10.1016/j.matdes.2022.111458
    DORA PSI
  • Pandiyan V, Masinelli G, Claire N, Le-Quang T, Hamidi-Nasab M, de Formanoir C, et al.
    Deep learning-based monitoring of laser powder bed fusion process on variable time-scales using heterogeneous sensing and operando X-ray radiography guidance
    Additive Manufacturing. 2022; 58: 103007 (15 pp.). https://doi.org/10.1016/j.addma.2022.103007
    DORA PSI
  • Glerum JA, Hocine S, Chang CST, Kenel C, Van Petegem S, Casati N, et al.
    Operando X-ray diffraction study of thermal and phase evolution during laser powder bed fusion of Al-Sc-Zr elemental powder blends
    Additive Manufacturing. 2022; 55: 102806 (12 pp.). https://doi.org/10.1016/j.addma.2022.102806
    DORA PSI
  • Ghasemi-Tabasi H, de Formanoir C, Van Petegem S, Jhabvala J, Hocine S, Boillat E, et al.
    Direct observation of crack formation mechanisms with operando laser powder bed fusion X-ray imaging
    Additive Manufacturing. 2022; 51: 102619 (11 pp.). https://doi.org/10.1016/j.addma.2022.102619
    DORA PSI
  • Hocine S, Van Swygenhoven H, Van Petegem S
    Verification of selective laser melting heat source models with operando X-ray diffraction data
    Additive Manufacturing. 2021; 37: 101747 (16 pp.). https://doi.org/10.1016/j.addma.2020.101747
    DORA PSI
  • Hocine S, Van Petegem S, Frommherz U, Tinti G, Casati N, Grolimund D, et al.
    A miniaturized selective laser melting device for operando X-ray diffraction studies
    Additive Manufacturing. 2020; 34: 101194 (9 pp.). https://doi.org/10.1016/j.addma.2020.101194
    DORA PSI
  • Hocine S, Van Swygenhoven H, Van Petegem S, Chang CST, Maimaitiyili T, Tinti G, et al.
    Operando X-ray diffraction during laser 3D printing
    Materials Today. 2020; 34: 30-40. https://doi.org/10.1016/j.mattod.2019.10.001
    DORA PSI

Dr. Steven Van Petegem
Structure and Mechanics of Advanced Materials
Center for Photon Science
Paul Scherrer Institute
E-mail: steven.vanpetegem@psi.ch