Mapping Spatial Distribution of Pores in an Additively Manufactured Gold Alloy Using Neutron Microtomography

Ghasemi-Tabasi, Hossein; Trtik, Pavel; Jhabvala, Jamasp; Meyer, Michael; Carminati, Chiara; Ströbl, Markus; Logé, Roland E.

doi:10.3390/app11041512

Cited by 6 publications

(3 citation statements)

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“…This dependence as well as effects of post processing have been widely studied, mainly based on simulations [22][23][24][25] and ex situ characterization techniques, such as XRD 5,17,26 , optical 27 and electron microscopy 19,28 . The effect of laser parameters on roughness, porosity and other structural defects is frequently investigated after manufacturing using X-ray 19,[29][30][31] and neutron 32 tomography.…”

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confidence: 99%

Operando tomographic microscopy during laser-based powder bed fusion of alumina

Makowska,

Verga,

Pfeiffer

et al. 2023

Commun Mater

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Laser-based Powder Bed Fusion (LPBF) of oxide ceramics enables fabrication of objects with complex three-dimensional shapes. However, mechanical properties of dense LPBF-manufactured ceramics are poor due to large amount of structural defects. Here, we perform the operando tomographic microscopy during LPBF of a magnetite-modified alumina to gain a deeper understanding of the underlying mechanisms. The effect of the laser energy density on the surface roughness, powder denudation zone and porosity formation mechanisms are investigated. Increasing laser power results in significant increase of the melt pool width, but not its depth and no melt pool depression is observed. Forces due to the recoil pressure are not seen to significantly influence the melt pool dynamics. Increasing power allows to avoid fusion porosity but enhances formation of spherical porosity that is formed by either reaching boiling point of liquid alumina, or by introducing gas bubbles by injection of hollow powder particles into the liquid.

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mentioning

confidence: 99%

Operando tomographic microscopy during laser-based powder bed fusion of alumina

Makowska,

Verga,

Pfeiffer

et al. 2023

Commun Mater

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show abstract

“…The effect of laser parameters on roughness, porosity and other structural defects is frequently investigated after manufacturing using X-ray 19,26−28 and neutron 29 tomography.…”

Section: Introductionmentioning

confidence: 99%

Operando tomographic microscopy during laser-based powder bed fusion

Makowska

Verga

Pfeiffer

et al. 2022

Preprint

View full text Add to dashboard Cite

Laser-based Powder Bed Fusion (LPBF) of oxide ceramics enables fabrication of objects with complex three-dimensional shapes, which are impossible to achieve using conventional manufacturing routes. However, mechanical properties of dense LPBF-manufactured ceramics are very poor due to large amount of structural defects. To acquaint deeper understanding of the underlying mechanisms, operando tomographic microscopy during LPBF of a magnetite-modified alumina using a pulsed, green laser has been carried out. Operando 3-dimensional information provides an insight into phenomena not accessible with other techniques. The effect of the laser energy density on the surface roughness, powder denudation zone and porosity formation mechanisms is investigated. Using increasing power results in significant increase of the melt pool width, but not of its depth and no melt pool depression is observed. For the investigated ceramic system, the forces due to the recoil pressure do not significantly influence the melt pool dynamics. Increasing power leads to avoid the lack of fusion porosity, but enhances formation of spherical porosity that is formed by either reaching boiling point of liquid alumina, or by introducing gas bubbles by injection of hollow powder particles into the liquid.

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“…Eleven publications report about very different topics from the application of neutron imaging, starting with an instrument at the NEUTRA facility (Switzerland) using neutrons and X-rays that was reported [1], followed by the work of the Australian imaging group, which presented new mathematical methods for reconstructing strain from energy-resolved neutron images [2]. The Swiss imaging group made a second contribution, investigating the mapping of the spatial distribution of pores using neutron microtomography [3], and from Japan a new method was presented dealing with the inner information of crystalline grain realized by wavelength-resolved neutron imaging [4].…”

mentioning

confidence: 99%