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8. Metal Additive Manufacturing of Space Components @ DLR

Author

Artzt, Katia Juliane, Bauer, Peter-Philipp, Gussone, Joachim, Kasperovich, Galina, Barriobero Vila, Pere, Requena, Guillermo, Haubrich, Jan, Kitsche, Wolfgang, Riccius, Jörg, Suslov, Dmitry, Kleinert, Jan, Rosauer, Philipp, Siggel, Martin, and Hümbert, Simon

Subjects
LPBF, Additive Manufacturing, space components
Published
2022

13. The effect of build direction and geometric optimization in laser powder bed fusion of Inconel 718 structures with internal channels

Author

Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Kasperovich, Galina, Becker, Ralf, Artzt, Katia, Barriobero Vila, Pere, Requena, Guillermo, Haubrich, Jan, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Kasperovich, Galina, Becker, Ralf, Artzt, Katia, Barriobero Vila, Pere, Requena, Guillermo, and Haubrich, Jan

Abstract

A laser powder bed fusion (LPBF) strategy was developed for manufacturing small channels with high dimensional accuracy in Inconel 718 structures. Particular attention was paid to surface characteristics such as equivalent diameter and shape factor. The inherent surface quality of external surfaces was optimized by a systematic variation of the LPBF contour parameters as well as the channel cross-section. The mean arithmetic roughness Sa was analysed for upskin, vertical and downskin surfaces with respect to the build platform. Simultaneously, the effect of the build direction on the quality of internal free-shaped surfaces was investigated on channels with diameters from 500 to 1000 µm and build orientations from the horizontal (0°) to vertical (90°). A significant improvement in dimensional accuracy was achieved by using an optimized droplet-shaped cross-section that is scaled as a function with the build inclination. An angular analysis of the surface roughness in different regions of the channels confirms that this modified cross-section reduces the fraction of channel regions that show a particularly high surface roughness due to inward melting. In combination with an optimized contour processing strategy, the modified channel resulted in the best properties for inclinations below 45°. The shape factor increased from 0.4 to almost 0.9, i.e., close to the ideally round shape., Peer Reviewed, Postprint (published version)

Published
2021

20. Mapping the geometry of Ti-6Al-4V: from martensite decomposition to localized spheroidization during selective laser melting

Author

Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Barriobero Vila, Pere, Artzt, Katia, Stark, Andreas, Schell, Norbert, Siggel, Martin, Gussone, Joachim, Kleinert, Jan, Kitsche, Wolfgang, Requena, Guillermo, Haubrich, Jan, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Barriobero Vila, Pere, Artzt, Katia, Stark, Andreas, Schell, Norbert, Siggel, Martin, Gussone, Joachim, Kleinert, Jan, Kitsche, Wolfgang, Requena, Guillermo, and Haubrich, Jan

Abstract

The influence that complex component geometries can have on microstructure formation is investigated in a rocket engine impeller fabricated of a Ti-6Al-4V alloy by selective laser melting (SLM). The SLM melt pool monitoring, indicative of the component's thermal history during processing, is linked to the bulk mapping of martensite decomposition obtained by high energy synchrotron X-ray diffraction. In addition to the martensitic and lamellar microstructures typically obtained during SLM of Ti-6Al-4V, spheroidization is identified to take place in the component's down-skin regions. Grain boundary migration may contribute to the latter effect. Small recrystallized grains form along grain boundaries., Peer Reviewed, Postprint (author's final draft)

Published
2020

21. Pandora’s box–influence of contour parameters on roughness and subsurface residual stresses in laser powder bed fusion of Ti-6Al-4V

Author

Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Artzt, Katia, Mishurova, Tatiana, Bauer, Peter, Gussone, Joachim, Barriobero Vila, Pere, Evsevleev, S, Bruno, Giovanni, Requena, Guillermo, Haubrich, Jan, Universitat Politècnica de Catalunya. Departament de Ciència i Enginyeria de Materials, Universitat Politècnica de Catalunya. CIEFMA-PROCOMAME - Disseny Microestructural i Fabricació Avançada de Materials, Artzt, Katia, Mishurova, Tatiana, Bauer, Peter, Gussone, Joachim, Barriobero Vila, Pere, Evsevleev, S, Bruno, Giovanni, Requena, Guillermo, and Haubrich, Jan

Abstract

The contour scan strategies in laser powder bed fusion (LPBF) of Ti-6Al-4V were studied at the coupon level. These scan strategies determined the surface qualities and subsurface residual stresses. The correlations to these properties were identified for an optimization of the LPBF processing. The surface roughness and the residual stresses in build direction were linked: combining high laser power and high scan velocities with at least two contour lines substantially reduced the surface roughness, expressed by the arithmetic mean height, from values as high as 30 µm to 13 µm, while the residual stresses rose from ~340 to about 800 MPa. At this stress level, manufactured rocket fuel injector components evidenced macroscopic cracking. A scan strategy completing the contour region at 100 W and 1050 mm/s is recommended as a compromise between residual stresses (625 MPa) and surface quality (14.2 µm). The LPBF builds were monitored with an in-line twin-photodiode-based melt pool monitoring (MPM) system, which revealed a correlation between the intensity quotient I2/I1, the surface roughness, and the residual stresses. Thus, this MPM system can provide a predictive estimate of the surface quality of the samples and resulting residual stresses in the material generated during LPBF., Peer Reviewed, Postprint (published version)

Published
2020

25. Numerische und experimentelle Untersuchungen zum anisotropen Kriechverhalten von oxidkeramischen Faserverbundwerkstoffen

Author

Artzt, Katia J. (Dipl.-Ing.)

Subjects
Kriechen, Faserverbundwerkstoff, Porosität, Hochtemperaturverhalten, ddc:620, Keramik
Abstract

Die vorliegende Arbeit befasst sich mit dem Kriechverhalten eines oxidkeramischen Faserverbundwerkstoffs (CMC) mit poröser Matrix. Anhand von unidirektionalem Material wird das Verformungsverhalten bei hoher Temperatur unter Druck, Biegung und Zug charakterisiert und Daten für nachfolgende Simulationen generiert. In Simulationen auf der Mikroskala werden anhand von parametrisierten 3D-Einheitszellen und 2D-Modellen die Einflussfaktoren Faseranordnung, Faservolumengehalt, Lastrandbedingungen und elastische Eigenschaften auf das Druckkriechverhalten in verschiedenen Belastungsrichtungen untersucht. Dabei werden insbesondere die Unterschiede herausgearbeitet, die sich durch die Porosität der Matrix des untersuchten CMCs im Vergleich zu einem CMC mit dichter Matrix ergeben. Zur Beschreibung des anisotropen Kriechverhaltens auf der Mesoebene wird ein bestehendes Materialmodell modifiziert, in Finite-Elemente Modelle implementiert und anhand von Druck- und Biegekriechsimulationen überprüft.

Published
2018

27. Selective Laser Melting of CuCr1Zr

Author

Artzt, Katia, Haubrich, Jan, and Requena, Guillermo

Subjects
CuCr1Zr, Selective Laser Melting, additive manufacturing
Published
2017

30. 3-dimensional microstructure characterization of porous ceramic matrix composites by X-ray tomography and FIB-slicing as database for numerical modelling

Author

Bartsch, Marion, Artzt, Katia, Manero, Albert, Kenesei, Peter, Eggeler, Mario, and Watermeyer, Philipp

Subjects
CMC, Ceramic Matrix Composite, Experimentelle und numerische Methoden, Tomography, Microstructure, Modelling
Abstract

All-oxide ceramic composites (CMC) are developed for applications in combustion chambers of gas turbines as an alternative for metallic materials aiming at reduction of fuel consumption and NOx emission. At DLR a CMC is processed by winding an endless alumina fibre bundle, which is infiltrated by aqueous alumina slurry, on a mandrel and further sintering of the generated ceramic ‘green body’. The result is a CMC with complex hierarchical microstructure, which is controlled by the processing parameters. Fibre arrangement, fibre volume fraction, and matrix porosity can be varied in a wide range. For determining the effect of the complex microstructure on the resulting mechanical properties, numerical models are typically based on microstructural parameters derived from microscopic analyses of cross sections. A challenge is deriving correct 3-dimensional geometry data for the numerical model from such 2-dimensional images. A distinct improvement is provided by non-destructive X-ray tomography on the length scale from mm to µm and by combined sequential focused ion beam (FIB) ablation and scanning electron microscopy, which allows for construction of 3-dimensional microstructure features in the submicron range.

Published
2016

33. Abschlussbericht LOCCA - Low NOx Oxide Ceramic Combustors for Aero-Engines

Author

Behrendt, Thomas, Hackemann, Stefan, Artzt, Katia, Aumeier, Thomas, Seiler, Patrick, Heinze, Johannes, Lange, Lena, Schroll, Michael, Doll, Ulrich, Fischer, Michael, Shi, Yuan, and Hassa, Christoph

Subjects
Brennkammer, FEM, Triebwerk, Lasermesstechnik, Kühlfilm, Wärmedämmschicht, Brennerströmung, CFD, Faserverbundkeramik
Published
2015

34. Real Time Testing of High Temperature Aerospace Materials

Author

Williams, Hunter, Sofronsky, Stephen, Manero, Albert, Okasinski, John, Almer, Jonathan, Meid, Carla, Wischek, Janine, Bartsch, Marion, Hackemann, Stefan, Artzt, Katia, and Raghavan, Seetha

Subjects
In-situ X-ray diffraction, Ceramic Matrix composites, Thermal barrier coatings, Piezospectroscopy
Published
2015

47. Development of alloys for laser additive manufacturing

Author

Barriobero Vila, Pere, Artzt, Katia Juliane, Gussone, Joachim, Stark, Andreas, Schell, Norbert, Kitsche, Wolfgang, Haubrich, Jan, and Requena, Guillermo

Subjects
synchrotron-based characterization, Metal additive manufactururing, engineering alloys

48. Additive Manufacturing of Components for Rocket Propulsion

Author

Artzt, Katia Juliane, Barriobero Vila, Pere, Gussone, Joachim, Bauer, Peter-Philipp, Kasperovich, Galina, Löbbecke, Miriam, Requena, Guillermo, Riccius, Jörg, Suslov, Dmitry, Hümbert, Simon, and Haubrich, Jan

Subjects
Additive Manufacturing

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