Effect of preheating on the thermal, microstructural and mechanical properties of selective electron beam melted Ti-6Al-4V components
| Autor: | Peter D. Lee, Sara Nonni, Emmanuel Muzangaza, Philip J. Withers, Riccardo Tosi, Chu Lun Alex Leung |
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| Jazyk: | angličtina |
| Předmět: |
Technology
X-ray computed tomography (CT) Materials science Scanning electron microscope Additive manufacturing Materials Science Dimensional accuracy Materials Science Multidisciplinary 02 engineering and technology PORE 010402 general chemistry 01 natural sciences Tortuosity Indentation hardness POWDER BED Thermal conductivity Thermal lcsh:TA401-492 General Materials Science Composite material 0912 Materials Engineering Anisotropy Porosity Materials Science & Technology Mechanical Engineering 021001 nanoscience & nanotechnology 0910 Manufacturing Engineering 0104 chemical sciences Image-based modelling Mechanics of Materials Preheating Cathode ray lcsh:Materials of engineering and construction. Mechanics of materials 0210 nano-technology 0913 Mechanical Engineering |
| Zdroj: | Materials & Design Materials & Design, Vol 174, Iss, Pp-(2019) Leung, C L A, Tosi, R, Muzangaza, E, Nonni, S, Withers, P J & Lee, P D 2019, ' Effect of preheating on the thermal, microstructural and mechanical properties of selective electron beam melted Ti-6Al-4V components ', Materials and Design, vol. 174, 107792 . https://doi.org/10.1016/j.matdes.2019.107792 |
| ISSN: | 0264-1275 |
| DOI: | 10.1016/j.matdes.2019.107792 |
| Popis: | 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, EA) 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 EA 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 EA (411 kJ m−2) is sufficient to produce components with a high hardness whilst optimising build accuracy. Keywords: Preheating, Thermal conductivity, Additive manufacturing, Dimensional accuracy, X-ray computed tomography (CT), Image-based modelling |
| Databáze: | OpenAIRE |
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