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In-situ Synchrotron imaging of keyhole mode multi-layer laser powder bed fusion additive manufacturing

Chen, Y; Clark, SJ; Leung, CLA; Sinclair, L; Marussi, S; Olbinado, MP; Boller, E; ... Lee, PD; + view all (2020) In-situ Synchrotron imaging of keyhole mode multi-layer laser powder bed fusion additive manufacturing. Applied Materials Today , 20 , Article 100650. 10.1016/j.apmt.2020.100650. Green open access

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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.

Type: Article
Title: In-situ Synchrotron imaging of keyhole mode multi-layer laser powder bed fusion additive manufacturing
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.apmt.2020.100650
Publisher version: http://dx.doi.org/10.1016/j.apmt.2020.100650
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Additive manufacturing, laser powder bed fusion, Keyhole mode, Synchrotron X-ray imaging
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/10099081
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