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In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing

The laser–matter interaction and solidification phenomena associated with laser additive manufacturing (LAM) remain unclear, slowing its process development and optimisation. Here, through in situ and operando high-speed synchrotron X-ray imaging, we reveal the underlying physical phenomena during t...

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Autores principales: Leung, Chu Lun Alex, Marussi, Sebastian, Atwood, Robert C., Towrie, Michael, Withers, Philip J., Lee, Peter D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893568/
https://www.ncbi.nlm.nih.gov/pubmed/29636443
http://dx.doi.org/10.1038/s41467-018-03734-7
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author Leung, Chu Lun Alex
Marussi, Sebastian
Atwood, Robert C.
Towrie, Michael
Withers, Philip J.
Lee, Peter D.
author_facet Leung, Chu Lun Alex
Marussi, Sebastian
Atwood, Robert C.
Towrie, Michael
Withers, Philip J.
Lee, Peter D.
author_sort Leung, Chu Lun Alex
collection PubMed
description The laser–matter interaction and solidification phenomena associated with laser additive manufacturing (LAM) remain unclear, slowing its process development and optimisation. Here, through in situ and operando high-speed synchrotron X-ray imaging, we reveal the underlying physical phenomena during the deposition of the first and second layer melt tracks. We show that the laser-induced gas/vapour jet promotes the formation of melt tracks and denuded zones via spattering (at a velocity of 1 m s(−1)). We also uncover mechanisms of pore migration by Marangoni-driven flow (recirculating at a velocity of 0.4 m s(−1)), pore dissolution and dispersion by laser re-melting. We develop a mechanism map for predicting the evolution of melt features, changes in melt track morphology from a continuous hemi-cylindrical track to disconnected beads with decreasing linear energy density and improved molten pool wetting with increasing laser power. Our results clarify aspects of the physics behind LAM, which are critical for its development.
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spelling pubmed-58935682018-04-13 In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing Leung, Chu Lun Alex Marussi, Sebastian Atwood, Robert C. Towrie, Michael Withers, Philip J. Lee, Peter D. Nat Commun Article The laser–matter interaction and solidification phenomena associated with laser additive manufacturing (LAM) remain unclear, slowing its process development and optimisation. Here, through in situ and operando high-speed synchrotron X-ray imaging, we reveal the underlying physical phenomena during the deposition of the first and second layer melt tracks. We show that the laser-induced gas/vapour jet promotes the formation of melt tracks and denuded zones via spattering (at a velocity of 1 m s(−1)). We also uncover mechanisms of pore migration by Marangoni-driven flow (recirculating at a velocity of 0.4 m s(−1)), pore dissolution and dispersion by laser re-melting. We develop a mechanism map for predicting the evolution of melt features, changes in melt track morphology from a continuous hemi-cylindrical track to disconnected beads with decreasing linear energy density and improved molten pool wetting with increasing laser power. Our results clarify aspects of the physics behind LAM, which are critical for its development. Nature Publishing Group UK 2018-04-10 /pmc/articles/PMC5893568/ /pubmed/29636443 http://dx.doi.org/10.1038/s41467-018-03734-7 Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Leung, Chu Lun Alex
Marussi, Sebastian
Atwood, Robert C.
Towrie, Michael
Withers, Philip J.
Lee, Peter D.
In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing
title In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing
title_full In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing
title_fullStr In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing
title_full_unstemmed In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing
title_short In situ X-ray imaging of defect and molten pool dynamics in laser additive manufacturing
title_sort in situ x-ray imaging of defect and molten pool dynamics in laser additive manufacturing
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893568/
https://www.ncbi.nlm.nih.gov/pubmed/29636443
http://dx.doi.org/10.1038/s41467-018-03734-7
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