@misc{BambachFuegenschuhBuhletal., author = {Bambach, Markus and F{\"u}genschuh, Armin and Buhl, Johannes and Jensch, Felix and Schmidt, Johannes}, title = {Mathematical Modeling and Optimization for Powder-Based Additive Manufacturing}, series = {Procedia Manufacturing; Part of Special issue: 23rd International Conference on Material Forming}, volume = {47}, journal = {Procedia Manufacturing; Part of Special issue: 23rd International Conference on Material Forming}, editor = {Bambach, Markus}, issn = {2351-9789}, doi = {10.1016/j.promfg.2020.04.158}, pages = {1159 -- 1163}, language = {en} } @misc{SzczepańskiBambachJenschetal., author = {Szczepański, Łukasz and Bambach, Markus and Jensch, Felix and Ambroziak, Andrzej and Kurzynowski, Tomasz}, title = {Structural investigations of Fe-Zr-Si-Cu metallic glass with low glass-forming ability produced in laser powder bed fusion technology}, series = {Materials \& Design}, volume = {Vol. 210}, journal = {Materials \& Design}, issn = {0264-1275}, doi = {https://doi.org/10.1016/j.matdes.2021.110112}, pages = {7}, language = {en} } @misc{DeillonJenschPalmetal., author = {Deillon, L{\´e}a and Jensch, Felix and Palm, Frank and Bambach, Markus}, title = {A new high strength Al-Mg-Sc alloy for laser powder bed fusion with calcium addition to effectively prevent magnesium evaporation}, series = {Journal of materials processing technology}, volume = {Vol. 300}, journal = {Journal of materials processing technology}, issn = {1873-4774}, doi = {10.1016/j.jmatprotec.2021.117416}, pages = {10}, language = {en} } @misc{JenschEissingRichardetal., author = {Jensch, Felix and Eissing, Katharina and Richard, Williams and Trautmann, Marcus and Yang, Yitong and Dubinin, Sergej and H{\"a}rtel, Sebastian}, title = {Improving the structural integrity of challenging to manufacture LPBF components with toolpath correction}, series = {Materials Research Proceedings}, volume = {41}, journal = {Materials Research Proceedings}, publisher = {Materials Research Forum LLC}, issn = {2474-395X}, doi = {10.21741/9781644903131-12}, pages = {110 -- 119}, abstract = {This work deals with the influence of optimised exposure strategies on the distortion and microstructure of components susceptible to overheating and warpage. Therefore, different distortion-prone specimen geometries of 316L were fabricated with the standard parameters, as well as with exposure strategies optimised by machine learning, which were generated using the AMAIZE software package. The manufactured samples were analysed with regard to distortion. The results of the distortion analysis were then linked with the results of the digital tomography from AMAIZE. Furthermore, components were manufactured that tend to overheat due to their geometry and orientation on the substrate plate. The influence of overheating during the LPBF process on the microstructure and porosity was investigated along the build-up direction by means of an EBSD analysis and a porosity analysis. With the presented approach for optimising the exposure strategy with AMAIZE, it could be shown that a successful production of distortion- prone components with a porosity of less than 1 \% is possible in the first trial.}, language = {en} } @misc{GruegerJenschDittrichetal., author = {Gr{\"u}ger, Lennart and Jensch, Felix and Dittrich, Fabian and H{\"a}rtel, Sebastian}, title = {On the creation of a material bond between L-PBF-manufactured AZ91 and Ti-6Al-4V components in the context of medical applications}, series = {Materials}, volume = {17}, journal = {Materials}, number = {18}, publisher = {MDPI AG}, issn = {1996-1944}, doi = {10.3390/ma17184667}, abstract = {Within the scope of these investigations, the feasibility of a material bond between Ti-6Al-4V and the magnesium alloy AZ91 is analyzed. Ti-6Al-4V is frequently used for implants due to its biocompatibility, corrosion resistance, and specific strength. However, depending on the surface quality, the attachment behavior of the bone to the implant varies. Magnesium implants promote the regeneration of bone tissue and biodegrade as the bone tissue heals. Combining the properties of both materials in one implant enables a reduced implant volume and increased stability. For this reason, this study aims to demonstrate the feasibility of creating a material bond between the materials Ti-6Al-4V and AZ91. For this purpose, Ti-6Al-4V truncated cones and AZ91 sleeves were produced using the additive manufacturing process of laser powder bed fusion (L-PBF). The as-built sleeves were then pressed onto machined truncated cones. Since zinc serves as a lubricant and has good diffusion properties with the materials used as a result of heat treatment, a comparison was made between zinc-coated and the as-built Ti-6Al-4V samples. This showed that a bond was created after hot isostatic pressing and that the push-out force could be increased by more than 4.5 times. Consequently, a proof of feasibility was demonstrated, and a high potential for applications in medical technology was shown.}, language = {en} } @misc{JenschBuhlLaueetal., author = {Jensch, Felix and Buhl, Johannes and Laue, Robert and H{\"a}rtel, Sebastian}, title = {Application of the plane-strain-compression-test to determine the local mechanical properties of LPBF-manufactured 316l components}, series = {Material Forming: The 26th International ESAFORM Conference on Material Forming, Krak{\´o}w, Poland, April 19-21, 2023}, volume = {28}, journal = {Material Forming: The 26th International ESAFORM Conference on Material Forming, Krak{\´o}w, Poland, April 19-21, 2023}, doi = {10.21741/9781644902479-17}, pages = {149 -- 149}, language = {en} } @misc{SchmidtJenschHaertel, author = {Schmidt, Alexander and Jensch, Felix and H{\"a}rtel, Sebastian}, title = {Multi-material additive manufacturing-functionally graded materials by means of laser remelting during laser powder bed fusion}, series = {Frontiers of Mechanical Engineering}, volume = {18}, journal = {Frontiers of Mechanical Engineering}, number = {4}, issn = {2095-0233}, doi = {10.1007/s11465-023-0765-z}, pages = {1 -- 11}, abstract = {Many processes may be used for manufacturing functionally graded materials. Among them, additive manufacturing seems to be predestined due to near-net shape manufacturing of complex geometries combined with the possibility of applying different materials in one component. By adjusting the powder composition of the starting material layer by layer, a macroscopic and step-like gradient can be achieved. To further improve the step-like gradient, an enhancement of the in-situ mixing degree, which is limited according to the state of the art, is necessary. In this paper, a novel technique for an enhancement of the in-situ material mixing degree in the melt pool by applying laser remelting (LR) is described. The effect of layer-wise LR on the formation of the interface was investigated using pure copper and low-alloy steel in a laser powder bed fusion process. Subsequent cross-sectional selective electron microscopic analyses were carried out. By applying LR, the mixing degree was enhanced, and the reaction zone thickness between the materials was increased. Moreover, an additional copper and iron-based phase was formed in the interface, resulting in a smoother gradient of the chemical composition than the case without LR. The Marangoni convection flow and thermal diffusion are the driving forces for the observed effect.}, language = {en} } @misc{AlimovSviridovSydowetal., author = {Alimov, Artem and Sviridov, Alexander and Sydow, Benjamin and Jensch, Felix and H{\"a}rtel, Sebastian}, title = {Additive Manufacturing of Hot-Forming Dies Using Laser Powder Bed Fusion and Wire Arc Direct Energy Deposition Technologies}, series = {Metals}, volume = {13}, journal = {Metals}, number = {11}, issn = {2075-4701}, doi = {10.3390/met13111842}, abstract = {Additive technologies are now widely used for the production of complex precise parts and have high potential for the production of forming dies. In this work, hot-forming dies optimized for additive manufacturing were developed and produced with wire arc direct energy deposition (WA-DED) and laser powder bed fusion (L-PBF) technologies. The concept of lightweight hot-forming dies with a 2D-lattice structure was developed, which reduced the weight of each die by 56\%, from 14.2 kg to 6.1 kg, in production using L-PBF. Maraging/precipitation-hardened steel 17-4PH was used as an alternative to traditional hot-working steels with slightly lower mechanical properties and a much higher processability in the additive manufacturing process. The workability of the manufactured dies was confirmed by forging tests on an industrial screw press.}, language = {en} } @misc{GruegerSzyndlerJenschetal., author = {Gr{\"u}ger, Lennart and Szyndler, Joanna and Jensch, Felix and H{\"a}rtel, Sebastian}, title = {Porosity analysis of L-PBF manufactured AZ91D components}, series = {Materials research proceedings}, volume = {54}, journal = {Materials research proceedings}, publisher = {Materials Research Forum LLC}, address = {Millersville, PA}, isbn = {978-1-64490-359-9}, issn = {2474-395X}, doi = {10.21741/9781644903599-22}, pages = {199 -- 208}, abstract = {Several materials for joint replacement parts approved in medical technology are being investigated. Magnesium alloys are very suitable for implants due to the similar strength properties between magnesium alloys and human bone. Therefore, the present work aims to examine the parameters for producing the magnesium alloy AZ91D. For this purpose, 16 samples were manufactured with varying laser power and exposure speed and examined using µCT analyses. As a result, densities between 99.56 and 95.21 percent were achieved. The samples with the lowest density were subjected to a HIP process to increase the relative density. However, a further µCT analysis revealed only minor positive effects of the HIP process. An analysis of the number and size of the pores indicates that the pores bonded together instead of being closed.}, language = {en} } @misc{SviridovAlimovJenschetal., author = {Sviridov, Alexander and Alimov, Artem and Jensch, Felix and Dubinin, Sergej and H{\"a}rtel, Sebastian}, title = {Influence of surface quality on performance of forging dies produced by additive manufacturing the role of post-processing in LPBF-manufactured X55 steel}, series = {Materials research proceedings}, volume = {54}, journal = {Materials research proceedings}, publisher = {Materials Research Forum LLC}, address = {Millersville, PA}, isbn = {978-1-64490-359-9}, issn = {2474-395X}, doi = {10.21741/9781644903599-27}, pages = {245 -- 253}, abstract = {Laser Powder Bed Fusion (LPBF) has become a key technology in additive manufacturing (AM), enabling the production of highly complex geometries and is increasingly applied in serial production. With the continuous expansion of processable materials, LPBF is now also being considered for the manufacturing of forging dies. However, LPBF application for tool steels such as H11 is limited by their susceptibility to hot cracking. Maraging steels like X55 present a promising alternative due to their superior resistance to such defects. A major advantage of this technology for forging dies lies in the potential elimination of extensive machining required to refine rough as-built surfaces, thereby streamlining and accelerating the production process. Achieving this goal requires systematic investigations into non-machining post-processing techniques for targeted surface modifications, along with a comprehensive evaluation of mechanical properties and surface integrity after post-processing. This study examines the influence of different post-processing methods on the surface quality, mechanical properties, and tribological behavior of LPBF-manufactured X55 (1.2709) specimens. To evaluate surface roughness and mechanical performance, slope specimens and tensile specimens were analyzed in different conditions: as-built, mechanically machined, sandblasted, and treated via Hirtisition®. Additionally, flat dies were produced and subjected to ring compression tests to determine friction factors under varying surface and lubrication conditions. The findings emphasize the crucial role of post-processing in optimizing the surface quality and functional performance of LPBF-manufactured forging tools, offering valuable insights for their further development.}, language = {en} } @misc{OkoloEissingWilliamsetal., author = {Okolo, Chukwuemeka and Eissing, Katharina and Williams, Richard and Jensch, Felix and Fergani, Omar and H{\"a}rtel, Sebastian}, title = {Investigation of the influence of AI-controlled process parameter adjustment on the mechanical properties of LBPF-manufactured parts}, series = {Materials research proceedings}, volume = {54}, journal = {Materials research proceedings}, publisher = {Materials Research Forum LLC}, address = {Millersville, PA}, isbn = {978-1-64490-359-9}, issn = {2474-395X}, doi = {10.21741/9781644903599-24}, pages = {218 -- 227}, abstract = {This study investigates the influence of machine learning (ML) based process parameter adjustments on the microstructure, relative density, and mechanical properties of laser powder bed fusion (LPBF)-manufactured components, focusing on AlSi10Mg and Ti6Al4V. The ML algorithm optimizes the thermal history by adjusting laser power and exposure time at the vector level, ensuring consistent cooling and solidification dynamics. Microscopy revealed a refined and homogeneous microstructure in the optimized AlSi10Mg samples, with reduced grain size (4.92 µm compared to 6.37 µm in non-optimized samples). Relative density analysis showed a significant improvement for optimized samples, achieving consistent values across top, middle, and bottom sections of the specimen. Hardness measurements confirmed the homogenized mechanical properties, with more uniform and elevated hardness values observed in optimized samples. This study demonstrates that ML-based process optimization minimizes defects like porosity and microcracks, enabling improved mechanical performance and efficient process qualification for LPBF-manufactured parts. The findings underline the potential of AI-driven solutions for addressing complex geometrical and thermal challenges in LPBF process.}, language = {en} } @misc{EmdadiJenschSzyndleretal., author = {Emdadi, Aliakbar and Jensch, Felix and Szyndler, Joanna and Huang, Hsuan-Po and H{\"a}rtel, Sebastian and Weiß, Sabine}, title = {Void closure behavior during hot forming of an Fe-Al alloy}, series = {Materials research proceedings}, volume = {54}, journal = {Materials research proceedings}, publisher = {IWA Publishing}, address = {Millersville, PA}, isbn = {978-1-64490-359-9}, issn = {2474-395X}, doi = {10.21741/9781644903599-99}, pages = {927 -- 935}, abstract = {Hot forging is a forming process that can be used as a post-processing treatment to close residual porosity and refine the microstructure of additively manufactured materials, resulting in improved mechanical properties. During hot forging, void closure occurs through plastic deformation resulting from a predominantly compressive stress state at elevated temperatures. In the present work, Fe-25Al-1.5Ta (at. \%) samples have been produced by laser powder bed fusion (LPBF) using a larger layer thickness and scan speed than commonly used to achieve a target porosity fraction of approximately 10\%. Full densification is attempted in the subsequent hot compression step at various height reduction ratios. The as-built LPBF samples contained 8-10\% voids. After deformation to true strains of 0.2, 0.4, and 0.6, the void fraction decreased significantly to approximately 4\%, 2.3\%, and 1.1\%, respectively. Hot compression resulted in the complete closure of large pores with a size range of 200-300 µm and a significant reduction in the size of small to medium pores. These results show potential for improving the productivity of the LPBF by speeding up the process by increasing layer thickness and scanning speed while maintaining a reasonable density. Full densification should be achieved by subsequent hot forging.}, language = {en} } @techreport{SchmidtJensch, author = {Schmidt, Alexander and Jensch, Felix}, title = {Vorrichtung und Verfahren zur additiven Fertigung eines Bauteils aus einem Pulverbett}, publisher = {Deutsches Patent- und Markenamt}, address = {M{\"u}nchen}, pages = {10}, abstract = {Ein Verfahren zur additiven Fertigung eines Bauteils aus einem Pulverbett umfassend die folgenden Schritte: A) Bereitstellen eines Pulvermaterials; B) {\"U}berf{\"u}hren des Pulvermaterials unter Ausbildung eines Pulverbetts; C) Energieeintrag und/oder Auftragen des Bindemittels in das Pulverbett unter lokaler Verschmelzung und/oder lokaler Verklebung des Pulvermaterials des Pulverbetts zu einem Teilsegment des Bauteils; und mehrfache Wiederholung der Schritte B und C zur Fertigstellung des Bauteils, dadurch gekennzeichnet, dass das Pulvermaterial vor oder w{\"a}hrend des Schrittes C, also als Sch{\"u}ttung und/oder im geschmolzenen und/oder verklebten Zustand, durch Einbringung von K{\"o}rperschall, insbesondere durch Ultraschallbehandlung, konditioniert wird; sowie eine Vorrichtung zur additiven Fertigung.}, language = {de} } @misc{EmdadiBolzJenschetal., author = {Emdadi, Aliakbar and Bolz, Sebastian and Jensch, Felix and Tovar, Michael and Weiß, Sabine}, title = {On the hot deformation of a Fe-Al-Ta iron aluminide prepared via laser powder bed fusion}, series = {Crystals}, volume = {13}, journal = {Crystals}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2073-4352}, doi = {10.3390/cryst13040627}, pages = {1 -- 12}, abstract = {In the present work, a combined process of laser powder bed fusion (LPBF) and hot working in terms of microstructure refinement was investigated for Fe-25Al-1.5Ta alloy samples. Uniaxial compression tests were carried out parallel and perpendicular to the building direction (BD) at 1000 °C, where BCC A2-phase was stable, at a strain rate of 0.0013 s-1. The true stress-true strain curves indicated a broad flow stress peak followed by a slight decrease, which is typical for dynamic recrystallization (DRX) of conventional BCC metals such as ferritic iron. A negligible dependence in the flow stress behavior on the compression direction was observed. DRX initiated at a stress of 18.7 MPa for the sample compressed parallel to the BD, corresponding to a true strain of 0.011, and at 18.1 MPa for the samples compressed normal to the BD, which corresponded to a true strain of 0.010. The microstructural investigations by electron backscatter diffraction (EBSD) showed that the relatively coarse and elongated grains of the as-LPBF builds were significantly refined after hot working. The microstructure of the compressed samples mainly consisted deformed grains. These were fragmented by sub-grains bounded by low-angle boundaries independent of the compression axis, indicating the occurrence of dynamic recovery (DRV) during hot working. In addition, a few equiaxed, small grains were observed in the pre-existing grain boundaries, which formed due to DRX. Most pores in the as-LPBF builds were closed after hot compression, particularly in the central region of the deformed specimens where the compressive stress state is dominant. In summary, hot compression reveals a practical thermomechanical post-processing treatment for Fe-Al-Ta iron aluminides built by LPBF. The hot working refines the epitaxially elongated microstructure of the as-LPBF builds by DRV/DRX and reduces the porosity.}, language = {en} } @misc{EmdadiYangSzyndleretal., author = {Emdadi, Aliakbar and Yang, Yitong and Szyndler, Joanna and Jensch, Felix and Ertugrul, G{\"o}khan and Tovar, Michael and H{\"a}rtel, Sebastian and Weiß, Sabine}, title = {Highly printable Fe₃Al intermetallic alloy}, series = {Metals : open access journal}, volume = {16}, journal = {Metals : open access journal}, number = {5}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/met16010005}, pages = {1 -- 15}, abstract = {Intermetallic Fe₃Al-based alloys reinforced with Laves-phase precipitates are emerging as potential replacements for conventional high-alloy steels and possibly polycrystalline Ni-based superalloys in structural applications up to 700 °C. Their impressive mechanical properties, however, are offset by limited fabricability and poor machinability due to their severe brittleness. High tool wear during finish-machining, which is still required for components such as turbine blades, remains a key barrier to their broader adoption. In contrast to conventional manufacturing routes, additive manufacturing offers a viable solution by enabling near-net-shape manufacturing of difficult-to-machine iron aluminides. In the present study, laser powder bed fusion was used to produce an Fe-25Al-1.5Ta intermetallic containing strengthening Laves-phase precipitates, and the porosity, microstructure and phase composition were characterized as a function of the process parameters. The results showed that preheating the build plate to 650 °C effectively suppressed delamination and macrocrack formation, even though noticeable cracking still occurred at the high scan speed of 1000 mm/s. X-ray tomography revealed that samples fabricated with a lower scan speed (500 mm/s) and a higher layer thickness (0.1 mm) contained larger, irregularly shaped pores, whereas specimens printed at the same volumetric energy density (40 J/mm3) but with different parameter sets exhibited smaller fractions of predominantly spherical pores. All samples contained mostly elongated grains that were either oriented close to <001> relative to the build direction or largely texture-free. X-ray diffraction confirmed the presence of Fe₃Al and C14-type (Fe, Al)₂Ta Laves phase in all samples. Hardness values fell within a narrow range (378-398 HV10), with only a slight reduction in the specimen exhibiting higher porosity.}, language = {en} } @misc{JenschSviridovDubininetal., author = {Jensch, Felix and Sviridov, Alexander and Dubinin, Sergej and Karabulut, Fatih and Weiß, Sabine and H{\"a}rtel, Sebastian}, title = {Parameter optimization for low-porosity Ti-6Al-4V parts produced using accelerated PBF-LB process}, series = {Progress in additive manufacturing}, journal = {Progress in additive manufacturing}, publisher = {Springer}, address = {Cham}, issn = {2363-9520}, doi = {10.1007/s40964-025-01510-w}, pages = {1 -- 17}, abstract = {In this study, the influence of various process parameters on the porosity of Ti-6Al-4V parts fabricated via Powder Bed Fusion - Laser Based (PBF-LB) is investigated. Three different layer thicknesses (30 μm, 60 μm, and 120 μm) were analyzed to define process windows enabling a build-rate acceleration while keeping the porosity below 0.1\%. Through iterative parameter refinement, the effects of laser power, scan speed and hatch distance were examined in terms of linear energy density (LED), energy transmission density (ETD) and volumetric energy density (VED), and their influence on the formation of process-related defects such as pores. Correlations between these energy metrics and pore formation types (keyhole vs. lack-of-fusion) are discussed. The results demonstrate that process acceleration by a factor of more than 3 is possible while maintaining high quality of the components in terms of internal porosity. In addition, an accelerated method for manufacturing components using the PBF-LB process is presented, in which components are manufactured at very high build-rates but with increased porosity and then brought to the target porosity of 0.1\% using the HIP process. This has made it possible to accelerate the build-rate in PBF-LB production by a further 32\%. Accounting for the additional time required for HIP, the HIP route is faster than using the accelerated, which achieves the target porosity in as-built condition, for parts larger than 1421 cm3.}, language = {en} }