Classifying shape of internal pores within AlSi10Mg alloy manufactured by laser powder bed fusion using 3D X-ray micro computed tomography: influence of processing parameters and heat treatment

James C Hastie; Mehmet Kartal; Luke N Carter; Moataz M Attallah; Daniel M Mulvihill

doi:10.1016/j.matchar.2020.110225

Classifying shape of internal pores within AlSi10Mg alloy manufactured by laser powder bed fusion using 3D X-ray micro computed tomography: influence of processing parameters and heat treatment

James C Hastie^* (Corresponding Author), Mehmet Kartal, Luke N Carter, Moataz M Attallah, Daniel M Mulvihill

^*Corresponding author for this work

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Abstract

Internal porosity of metallic parts manufactured by laser powder bed fusion (LPBF) is governed by processing parameters including laser power, scanning speed, scan spacing and layer thickness. To fully understand the influence of processing parameters it is important to categorise the shape of process defects (pores) in 3D beyond the degree of sphericity alone. In the present paper, AlSi10Mg samples were manufactured using 30 unique LPBF parameter combinations and analysed using high resolution X-ray micro computed tomography (XμCT). The shapes of individual pores are classified and studied using an approach based on the similarity of 3D pore descriptors with simplified artificial objects. Porosity within high as-fabricated densification builds can be reduced to virtually negligible by hot isostatic pressing (HIPping), which was found to fully or partially close (flatten) pores. Subsequent T6 treatment causes pores to reopen and resemble their original shape. The effects of treatment are sensitive to pore size.

Original language	English
Article number	110225
Number of pages	14
Journal	Materials Characterization
Volume	163
Early online date	28 Feb 2020
DOIs	https://doi.org/10.1016/j.matchar.2020.110225
Publication status	Published - 1 May 2020

Bibliographical note

The authors gratefully acknowledge the support provided by the EPSRC (grant EP/R021694/1). The authors also wish to thank Rosie Bird at the University of Aberdeen for assisting with Avizo.

Keywords

laser powder bed fusion
selective laser melting
X-ray micro computed tomography
porosity classification
hot isostatic pressing
T6 heat treatment
POROSITY
Laser powder bed fusion
QUANTIFICATION
Hot isostatic pressing
Porosity classification
MECHANICAL-PROPERTIES
Selective laser melting
MELTED ALSI10MG
MICROSTRUCTURE

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© 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Accepted author manuscript, 2.41 MBLicence: CC BY-NC-ND

Cite this

Hastie, J. C., Kartal, M., Carter, L. N., Attallah, M. M., & Mulvihill, D. M. (2020). Classifying shape of internal pores within AlSi10Mg alloy manufactured by laser powder bed fusion using 3D X-ray micro computed tomography: influence of processing parameters and heat treatment. Materials Characterization, 163, Article 110225. https://doi.org/10.1016/j.matchar.2020.110225

Classifying shape of internal pores within AlSi10Mg alloy manufactured by laser powder bed fusion using 3D X-ray micro computed tomography: influence of processing parameters and heat treatment. / Hastie, James C (Corresponding Author); Kartal, Mehmet; Carter, Luke N et al.
In: Materials Characterization, Vol. 163, 110225, 01.05.2020.

Research output: Contribution to journal › Article › peer-review

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title = "Classifying shape of internal pores within AlSi10Mg alloy manufactured by laser powder bed fusion using 3D X-ray micro computed tomography: influence of processing parameters and heat treatment",

abstract = "Internal porosity of metallic parts manufactured by laser powder bed fusion (LPBF) is governed by processing parameters including laser power, scanning speed, scan spacing and layer thickness. To fully understand the influence of processing parameters it is important to categorise the shape of process defects (pores) in 3D beyond the degree of sphericity alone. In the present paper, AlSi10Mg samples were manufactured using 30 unique LPBF parameter combinations and analysed using high resolution X-ray micro computed tomography (XμCT). The shapes of individual pores are classified and studied using an approach based on the similarity of 3D pore descriptors with simplified artificial objects. Porosity within high as-fabricated densification builds can be reduced to virtually negligible by hot isostatic pressing (HIPping), which was found to fully or partially close (flatten) pores. Subsequent T6 treatment causes pores to reopen and resemble their original shape. The effects of treatment are sensitive to pore size.",

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author = "Hastie, {James C} and Mehmet Kartal and Carter, {Luke N} and Attallah, {Moataz M} and Mulvihill, {Daniel M}",

note = "The authors gratefully acknowledge the support provided by the EPSRC (grant EP/R021694/1). The authors also wish to thank Rosie Bird at the University of Aberdeen for assisting with Avizo.",

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AU - Attallah, Moataz M

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Classifying shape of internal pores within AlSi10Mg alloy manufactured by laser powder bed fusion using 3D X-ray micro computed tomography: influence of processing parameters and heat treatment

Abstract

Bibliographical note

Keywords

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Mehmet Kartal

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Classifying shape of internal pores within AlSi10Mg alloy manufactured by laser powder bed fusion using 3D X-ray micro computed tomography: influence of processing parameters and heat treatment

Abstract

Bibliographical note

Keywords

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Mehmet Kartal

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