Leung, CLA;
Tosi, R;
Muzangaza, E;
Nonni, S;
Withers, PJ;
Lee, PD;
(2019)
Effect of preheating on the thermal, microstructural and mechanical properties of selective electron beam melted Ti-6Al-4V components.
Materials & Design
, 174
, Article 107792. 10.1016/j.matdes.2019.107792.
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Abstract
Two-stage preheating is used in selective electron beam melting (SEBM) to prevent powder spreading during additive manufacturing (AM); however, its effects on part properties have not been widely investigated. Here, we employed three different preheat treatments (energy per unit area, E_{A} to a Ti-6Al-4V powder bed. Each standalone build, we fabricated a large block sample and seven can-shaped samples containing sintered powder. X-ray computed tomography (XCT) was employed to quantify the porosity and build accuracy of the can-shaped samples. The effective thermal conductivity of the sintered powder bed was estimated by XCT image-based modelling. The microstructural and mechanical properties of the block sample were examined by scanning electron microscopy and microhardness testing, respectively. The results demonstrate that increasing E_{A} reduces the anisotropy of tortuosity and increases the thermal conductivity of the sintered powder bed, improving the heat transfer efficiency for subsequent beam-matter interaction. High preheat has a negligible effect on the porosity of large AM components; however, it decreases the microhardness from 330 ± 7 to 315 ± 11 HV0.5 and increases the maximum build error from 330 to 400 μm. Our study shows that a medium E_{A} (411 kJ m^{-2} is sufficient to produce components with a high hardness whilst optimising build accuracy.
| Type: | Article |
|---|---|
| Title: | Effect of preheating on the thermal, microstructural and mechanical properties of selective electron beam melted Ti-6Al-4V components |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.matdes.2019.107792 |
| Publisher version: | https://doi.org/10.1016/j.matdes.2019.107792 |
| Language: | English |
| Additional information: | © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Preheating, Thermal conductivity, Additive manufacturing, Dimensional accuracy, X-ray computed tomography (CT), Image-based modelling |
| 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/10073767 |
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