In-process failure analysis of thin-wall structures made by laser powder bed fusion additive manufacturing

Apratim Chakraborty, Reza Tangestani, Rasim Batmaz, Waqas Muhammad, Philippe Plamondon, Andrew Wessman, Lang Yuan, Étienne Martin

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Fabrication of thin-wall components using the laser powder bed fusion (LPBF) additive manufacturing (AM) technology was investigated for two “hard-to-weld” high gamma prime Ni-based superalloys RENÉ 65 (R65) and RENÉ 108 (R108). Simple block parts with wall thicknesses of 0.25 mm, 1.00 mm, and 5.00 mm are printed using a bidirectional laser scanning strategy without layer-wise rotation. Parts with walls thinner than 5 mm fail before reaching the designated build height. Results indicate that reduction of limiting build height (LBH) corresponds to the reduction of part thickness and is unaffected by alloy composition. On the contrary, the number of internal micro-cracks along columnar grain boundaries in the build direction (BD) increases with part thickness and is significantly higher in R108 than R65. These findings suggest that reduced LBH in parts with thinner walls is not caused by internal micro-crack formation. Fractography and finite element analysis (FEA) of the in-process thermal stresses show that the LBH trend is not explained by the conventional cracking mechanism. Simulations suggest that part thickness affects stress distribution leading to more substantial distortion and consequent failure to add layers for continued fabrication of thinner parts.

Original languageEnglish (US)
Pages (from-to)233-243
Number of pages11
JournalJournal of Materials Science and Technology
Volume98
DOIs
StatePublished - Jan 30 2022

Keywords

  • Additive manufacturing
  • Laser powder bed fusion
  • Residual stress
  • Superalloys
  • Thin-wall

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Polymers and Plastics
  • Metals and Alloys
  • Materials Chemistry

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