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Manufacturing defect-free superalloy components using laser powder bed fusion (L-
PBF) remains a challenging and urgent issue due to the high susceptibility of the
process to microcracking. While previous studies have investigated how individual
laser scanning parameters influence microcracking behavior in superalloy components,
a comprehensive process window for crack density has yet to be developed. Moreover,
the relationship between laser scanning conditions and crack density is often treated
as a black-box model, without explicitly considering the underlying fundamental
mechanisms. Thus, the purpose of this study is twofold: first, to establish a
comprehensive process window for crack density in order to fabricate defect-free
IN738LC components by L-PBF; and second, to elucidate the fundamental
mechanisms linking laser scanning conditions to solidification cracking through
empirical causal analysis based on microstructural features. To this end, more than
100 sets of laser scanning conditions were investigated, and the optimal conditions
were found to minimize the defect ratio and crack density to less than 0.060% and
0.005 mm-1, respectively. The suitability was further validated by fabricating turbine-
blade shaped parts without internal defects. Then, microstructural features for all
samples were extracted using electron backscatter diffraction, and the resulting
dataset was used to develop regression models for predicting crack density. The
multiple linear regression and support vector regression models revealed that two
common key microstructural features—grain refinement and the alignment of <001> to
the building direction—play a primary role in suppressing microcracking. On the other
hand, the findings also imply that incorporating additional metallurgical and mechanical
features may be essential for enhancing the predictive performance.

権利情報:

• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

キーワード: Laser powder bed fusion, Inconel 738 LC, Solidification cracking, Electron backscatter diffraction, Causal analysis

刊行年月日: 2025-07-18

出版者: Elsevier BV

掲載誌:

• JOURNAL OF MANUFACTURING PROCESSES (ISSN: 15266125) vol. 151 p. 354-371

研究助成金:

原稿種別: 出版者版 (Version of record)

MDR DOI:

公開URL: https://doi.org/10.1016/j.jmapro.2025.07.023

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更新時刻: 2025-07-24 12:30:19 +0900

MDRでの公開時刻: 2025-07-24 12:19:33 +0900