Thickness-dependent microstructural transition and mechanical response in thin-walled LPBF-printed Inconel 718 structures
Abstract
Thin-walled features are increasingly used in architected materials produced by laser powder bed fusion (LPBF), yet the influence of geometric thickness on microstructure, defect formation, and mechanical behavior remains poorly understood. This study investigates the effect of thickness reduction in LPBF-fabricated Inconel 718 samples using optimized parameters, with a focus on interlayer rotation and contour scanning. Comparison between bulk samples and thin beams of varying thicknesses reveals that decreasing thickness promotes grain refinement. Texture analysis revealed a strengthening of the <100> crystallographic orientation along the build direction. Density measurements and microstructural observations showed increased porosity in the thinnest beams, attributed to heat accumulation and shortened scanning tracks promoting keyhole formation. Contour scanning induces finer grains, and its increased fraction in thin beams significantly influences mechanical properties. This is evidenced by tensile tests showing increased variability and reduced ductility in thinner specimens, while yield strength increases in the thinnest samples due to grain refinement and the contribution of contour-induced fine microstructures. These results demonstrate that LPBF parameters optimized for bulk materials cannot be directly applied to thin-walled geometries and underline the need for geometry-adapted scan strategies when fabricating architected structures with fine features.
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BibTeX
@article{fouque2026thicknessdependent,
title = {{Thickness-dependent microstructural transition and mechanical response in thin-walled LPBF-printed Inconel 718 structures}},
author = {Chloé Fouqué and Serge Pascal and Ayoub Ladaci and Christina Baslari and Déborah Clement and Florent Ledrappier and Cédric Gourdin and Michel Schlegel},
journal = {Materials \& Design},
year = {2026},
month = oct,
doi = {10.1016/j.matdes.2026.117193},
url = {https://cea.hal.science/cea-05787652v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Thickness-dependent microstructural transition and mechanical response in thin-walled LPBF-printed Inconel 718 structures
AU - Chloé Fouqué
AU - Serge Pascal
AU - Ayoub Ladaci
AU - Christina Baslari
AU - Déborah Clement
AU - Florent Ledrappier
AU - Cédric Gourdin
AU - Michel Schlegel
PY - 2026
DA - 2026/10/07
JO - Materials & Design
DO - 10.1016/j.matdes.2026.117193
UR - https://cea.hal.science/cea-05787652v1
AB - Thin-walled features are increasingly used in architected materials produced by laser powder bed fusion (LPBF), yet the influence of geometric thickness on microstructure, defect formation, and mechanical behavior remains poorly understood. This study investigates the effect of thickness reduction in LPBF-fabricated Inconel 718 samples using optimized parameters, with a focus on interlayer rotation and contour scanning. Comparison between bulk samples and thin beams of varying thicknesses reveals that decreasing thickness promotes grain refinement. Texture analysis revealed a strengthening of the <100> crystallographic orientation along the build direction. Density measurements and microstructural observations showed increased porosity in the thinnest beams, attributed to heat accumulation and shortened scanning tracks promoting keyhole formation. Contour scanning induces finer grains, and its increased fraction in thin beams significantly influences mechanical properties. This is evidenced by tensile tests showing increased variability and reduced ductility in thinner specimens, while yield strength increases in the thinnest samples due to grain refinement and the contribution of contour-induced fine microstructures. These results demonstrate that LPBF parameters optimized for bulk materials cannot be directly applied to thin-walled geometries and underline the need for geometry-adapted scan strategies when fabricating architected structures with fine features.
SN - 0261-3069
SN - 0264-1275
ER -