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Tailoring the thermal conductivity of the powder bed in Electron Beam Melting (EBM) Additive Manufacturing

Smith, CJ, Tammas-Williams, S, Hernandez-Nava, E and Todd, I (2017) Tailoring the thermal conductivity of the powder bed in Electron Beam Melting (EBM) Additive Manufacturing. Scientific Reports, 7. ISSN 2045-2322

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Abstract

Metallic powder bed additive manufacturing is capable of producing complex, functional parts by repeatedly depositing thin layers of powder particles atop of each other whilst selectively melting the corresponding part cross-section into each layer. A weakness with this approach arises when melting overhanging features, which have no prior melted material directly beneath them. This is due to the lower thermal conductivity of the powder relative to solid material, which as a result leads to an accumulation of heat and thus distortion. The Electron Beam Melting (EBM) process alleviates this to some extent as the powder must first be sintered (by the beam itself) before it is melted, which results in the added benefit of increasing the thermal conductivity. This study thus sought to investigate to what extent the thermal conductivity of local regions in a titanium Ti-6Al-4V powder bed could be varied by imparting more energy from the beam. Thermal diffusivity and density measurements were taken of the resulting sintered samples, which ranged from being loosely to very well consolidated. It was found that the calculated thermal conductivity at two temperatures, 40 and 730 °C, was more than doubled over the range of input energies explored.

Item Type: Article
Uncontrolled Keywords: Science & Technology; Multidisciplinary Sciences; Science & Technology - Other Topics; ALLOY
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TK Electrical engineering. Electronics. Nuclear engineering
Divisions: Maritime & Mechanical Engineering (merged with Engineering 10 Aug 20)
Publisher: Nature Research
Related URLs:
Date Deposited: 11 Apr 2019 08:22
Last Modified: 04 Sep 2021 01:51
DOI or ID number: 10.1038/s41598-017-11243-8
URI: https://researchonline.ljmu.ac.uk/id/eprint/10533
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