Abstract
Background: Laser powder bed fusion (L-PBF) additive manufacturing (AM) is used for building metallic parts layer-by-layer and often generates non-uniform thermal gradients between layers during fabrication, resulting in the development of residual stresses when parts are cooled down.
Objective: The impact of modulated laser used during the L-PBF process on residual stresses in Inconel 718 (IN718) material was investigated. The impact of build directions on residual stress is also determined.
Methods: The contour method is employed to measure the full-field residual stress component on the cross-section of samples. A complementary residual stress measurement method, incremental hole drilling, was employed for obtaining in-plane residual stress components.
Results: The results show that the residual stress distribution is sensitive to the build direction, with a higher magnitude of residual stress in the direction of build than that in the transverse direction. Multiple measurements with the same manufacturing parameters show good repeatability.
Conclusion: Residual stresses in the as-built parts are significant and hence a further consideration regarding relieving residual stresses is required when post-thermal treatments are developed.
Objective: The impact of modulated laser used during the L-PBF process on residual stresses in Inconel 718 (IN718) material was investigated. The impact of build directions on residual stress is also determined.
Methods: The contour method is employed to measure the full-field residual stress component on the cross-section of samples. A complementary residual stress measurement method, incremental hole drilling, was employed for obtaining in-plane residual stress components.
Results: The results show that the residual stress distribution is sensitive to the build direction, with a higher magnitude of residual stress in the direction of build than that in the transverse direction. Multiple measurements with the same manufacturing parameters show good repeatability.
Conclusion: Residual stresses in the as-built parts are significant and hence a further consideration regarding relieving residual stresses is required when post-thermal treatments are developed.
| Original language | English |
|---|---|
| Journal | Experimental Mechanics |
| Early online date | 6 Dec 2023 |
| DOIs | |
| Publication status | E-pub ahead of print - 6 Dec 2023 |
Bibliographical note
Open access via the Springer AgreementFunding
The work was financially supported by the Lloyd’s Register Foundation, United Kingdom, a charitable foundation helping to protect life and property by supporting engineering‐related education, public engagement and the application of research. The authors would also like to thank the National Structural Integrity Research Centre (NSIRC) United Kingdom, a postgraduate engineering facility for industry-led research into structural integrity established and managed by TWI through a network of both national and international Universities.
Data Availability Statement
AvailabilityThe raw data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study. The processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.
Keywords
- Residual stresses
- The contour method
- Alloy IN718
- Laser methods
- Powder methods