In-situ Synchrotron imaging of keyhole mode multi-layer laser powder bed fusion additive manufacturing
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
The keyhole mode in laser powder bed fusion (LPBF) additive manufacturing can be associated with excessive porosity and spatter, however, the underlying physics in multilayer build conditions remain unclear. Here, we used ultra-fast synchrotron X-ray imaging to reveal this phenomena. We in investigated melt pool dynamics, keyhole porosity and spatter formation mechanisms and their impact in all layers of the build. We observed that the transient melt pool dynamics associated with the keyhole include: (I) keyhole initiation, (II) keyhole development, and (III) melt pool recovery. Porosity and spatter were associated with stages (II) and (III). We also discovered that droplet spatter can form due to the collapse of the keyhole recoil zone, causing molten particle agglomeration and ejection during stage (III). Our results clarify the transient dynamics behind the keyhole mode in a multi-layer LBPF process and can be used to guide the reduction in porosity and spatter in additive manufacturing.
Date Issued
2020-09
Date Acceptance
2020-03-30
Citation
Applied Materials Today, 2020, 20, pp.1-8
ISSN
2352-9407
Publisher
Elsevier BV
Start Page
1
End Page
8
Journal / Book Title
Applied Materials Today
Volume
20
Copyright Statement
© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Identifier
https://www.sciencedirect.com/science/article/pii/S2352940720300986?via%3Dihub
Subjects
0204 Condensed Matter Physics
0912 Materials Engineering
1007 Nanotechnology
Publication Status
Published
Article Number
100650
Date Publish Online
2020-05-07