| 1. |
- Brueckner, Frank, et al.
(författare)
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Enhanced manufacturing possibilities using multi-materials in laser metal deposition
- 2018
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Ingår i: Journal of laser applications. - : American Institute of Physics (AIP). - 1042-346X .- 1938-1387. ; 26:2, s. 10-12
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Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing (AM) addresses various benefits as the buildup of complex shaped parts, the possibility of functional integration, reduced lead times or the use of difficult machinable materials compared to conventional manufacturing possibilities. Beside these advantages, the use of more than one material in a component would strongly increase the field of applications in typical AM branches as energy, aerospace, or medical technology. By means of multi-material buildups, cost-intensive alloys could be only used in high-loaded areas of the part, whereas the remaining part could be fabricated with cheaper compositions. The selection of combined materials strongly depends on the requested thermophysical but also mechanical properties. Within this contribution, examples (e.g., used in the turbine business) show how alloys can be arranged to fit together, e.g., in terms of a well-chosen coefficient of thermal expansion. As can be seen in nature, the multi-material usage can be characterized by sharp intersections from one material to the other (e.g., in case of a thin corrosion protection), but also by graded structures enabling a smoother material transition (e.g., in case of dissimilar materials which are joined together without defects). The latter is shown for an example from aerospace within this paper. Another possibility is the simultaneous placement of several materials, e.g., hard carbide particles placed in a more ductile matrix composition. These particles can be varied in size (e.g., TiC versus WC). Also the ratio between carbides and matrix alloy can be adjusted depending on its application. Especially, nozzle-based free form fabrication technologies, e.g., laser metal deposition, enable the utilization of more than one material. Within this contribution, possibilities to feed more than one filler material are demonstrated. In addition, results of multi-material processes are shown. Finally, this work focuses on different (potential) applications, mainly on power generation, but also for medical technology or wear resistant components.
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| 2. |
- Brueckner, Frank, et al.
(författare)
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Fabrication of metallic multi-material components using Laser Metal Deposition
- 2017
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Ingår i: Solid Freeform Fabrication 2017. - : The University of Texas at Austin. ; , s. 2530-2538
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Meanwhile, Laser Metal Deposition (LMD) is a well-known Additive Manufacturing technology used in various industrial branches as energy, tooling or aerospace. It can be used for the fabrication of new components but also repair applications. So far, volume build-ups were mostly carried out with one single material only. However, loading conditions may strongly vary and, hence, the use of more than one material in a component would yield major benefits. By means of multi-material build-ups, cost-intensive alloys could be used in highly-loaded areas of the part, whereas the remaining part could be fabricated with cheaper compositions. The selection of combined materials strongly depends on the requested thermo-physical and mechanical properties. Within this contribution, possibilities of material combinations by LMD and selected examples of beneficial multi-material use are presented.
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| 3. |
- Hendl, Julius, et al.
(författare)
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NDE for Additive Manufacturing
- 2022. - 1
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Ingår i: Handbook of Nondestructive Evaluation 4.0. - Cham : Springer. - 9783030732066 - 9783030732059 ; , s. 665-696
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- By means of additive manufacturing (AM) complex-shaped parts can be manufactured using a broad range of different materials. The latter can be supplied in the form of powder, wire, paste material, or even as foil. Various technologies are covered by the term “Additive Manufacturing,” for example, direct energy deposition (DED), laser powder bed fusion (LPBF), fused filament fabrication (FFF), or binder jetting printing (BJP). In all varieties, parts are manufactured layer by layer which results in changed material properties compared to conventional manufacturing routes, for example, mechanical properties or fatigue life. To reach a conformal material deposition without defects such as lack of fusion, delamination or cracking, an optimal process window with well-chosen parameters (e.g., beam power, spot size, scanning speed) has to be identified.For nondestructive evaluation (NDE), different approaches can be used to classify AM manufactured parts regarding their defect structure and consequentially their performance:1.Process optimization and understanding of defect formation in order to prevent defects 2.In situ measurements by a variety of integrated sensors and (IR) cameras for direct process observations 3.Post-processing NDE methods such as ultrasonic testing, X-ray, or computer tomography (CT)If the three approaches are simultaneously executed, a prediction of the effect of defects can be made for certain cases.
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| 4. |
- Willner, Robin, et al.
(författare)
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Potential and challenges of additive manufacturing for topology optimized spacecraft structures
- 2020
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Ingår i: Journal of laser applications. - : American Institute of Physics (AIP). - 1042-346X .- 1938-1387. ; 32:3
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Tidskriftsartikel (refereegranskat)abstract
- This study focused on the potential of topology optimization (TO) for metallic tertiary structures of spacecrafts produced by the additive manufacturing (AM) technique laser powder bed fusion. First, a screening of existing conventionally manufactured products was carried out to evaluate the benefits of a redesign concerning product performance and the associated economic impact. As a result of the study, the most suitable demonstrator was selected. This reference structure was redesigned by TO taking into consideration the AM process constraints. Another major aim of this work was to evaluate the possibilities and challenges of AM (accuracies, surface quality, process parameters, postmachining, and mechanical properties) in addition to the redesign process. A comprehensive approach was implemented including detailed analysis of the powder, mechanical properties, in-process parameters, and nondestructive inspection (NDI). All measured values were used for a back loop to the design process, thereby providing a final robust redesign. Finally, the fine-tuned demonstrator was built up in an iterative process. The parts were tested under representative conditions for the application to verify the performance. The demonstrator qualification test campaign contained thermal cycling, vibration testing, static load testing, and NDI. Thus, an improvement in technology readiness level up to "near flight qualified" was reached.
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