TY - GEN A1 - Brandl, Erhard A1 - Viehweger, Bernd A1 - Michailov, Vesselin A1 - Leyens, Christoph T1 - Deposition of Ti-6Al-4V using laser and wire, part I: Microstructural properties of single beads KW - Titanium KW - Ti-6Al-4V KW - Microstructure KW - Additive manufacturing KW - Laser KW - Deposition Y1 - 2011 ER - TY - GEN A1 - Bähr, Martin A1 - Buhl, Johannes A1 - Radow, Georg A1 - Schmidt, Johannes A1 - Bambach, Markus A1 - Breuß, Michael A1 - Fügenschuh, Armin T1 - Stable honeycomb structures and temperature based trajectory optimization for wire-arc additive manufacturing T2 - Optimization and Engineering N2 - We consider two mathematical problems that are connected and occur in the layer-wise production process of a workpiece using wire-arc additive manufacturing. As the first task, we consider the automatic construction of a honeycomb structure, given the boundary of a shape of interest. In doing this, we employ Lloyd’s algorithm in two different realizations. For computing the incorporated Voronoi tesselation we consider the use of a Delaunay triangulation or alternatively, the eikonal equation. We compare and modify these approaches with the aim of combining their respective advantages. Then in the second task, to find an optimal tool path guaranteeing minimal production time and high quality of the workpiece, a mixed-integer linear programming problem is derived. The model takes thermal conduction and radiation during the process into account and aims to minimize temperature gradients inside the material. Its solvability for standard mixed-integer solvers is demonstrated on several test-instances. The results are compared with manufactured workpieces. KW - Mixed-integer linear programming KW - Geometric optimization KW - Eikonal equation KW - Heat transmission KW - Additive manufacturing KW - Centroidal Voronoi tesselation Y1 - 2021 U6 - https://doi.org/10.1007/s11081-020-09552-5 SN - 1573-2924 VL - 22 IS - 2 SP - 913 EP - 974 ER - TY - GEN A1 - Bambach, Markus A1 - Sizova, Irina A1 - Szyndler, Joanna A1 - Bennett, Jennifer A1 - Hyatt, Greg A1 - Cao, Jian A1 - Papke, Thomas A1 - Merklein, Marion T1 - On the hot deformation behavior of Ti-6Al-4V made by additive manufacturing T2 - Journal of Materials Processing Technology KW - Titanium KW - Additive manufacturing KW - Hot deformation Y1 - 2021 U6 - https://doi.org/10.1016/j.jmatprotec.2020.116840 SN - 0924-0136 SN - 1873-4774 VL - 288 ER - TY - GEN A1 - Sviridov, Alexander A1 - Alimov, Artem A1 - Jensch, Felix A1 - Dubinin, Sergej A1 - Härtel, Sebastian T1 - Influence of surface quality on performance of forging dies produced by additive manufacturing the role of post-processing in LPBF-manufactured X55 steel T2 - Materials research proceedings N2 - 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. KW - Additive manufacturing KW - L-PBF KW - Forging dies KW - Hot bulk forging KW - Friction KW - X55 Y1 - 2025 SN - 978-1-64490-359-9 U6 - https://doi.org/10.21741/9781644903599-27 SN - 2474-395X VL - 54 SP - 245 EP - 253 PB - Materials Research Forum LLC CY - Millersville, PA ER - TY - GEN A1 - Emdadi, Aliakbar A1 - Yang, Yitong A1 - Szyndler, Joanna A1 - Jensch, Felix A1 - Ertugrul, Gökhan A1 - Tovar, Michael A1 - Härtel, Sebastian A1 - Weiß, Sabine T1 - Highly printable Fe₃Al intermetallic alloy T2 - Metals : open access journal N2 - 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. KW - Fe₃Al intermetallic KW - Iron aluminide KW - Additive manufacturing KW - Laser powder bed fusion (LPBF) KW - Porosity KW - Microstructure Y1 - 2026 U6 - https://doi.org/10.3390/met16010005 VL - 16 IS - 5 SP - 1 EP - 15 PB - MDPI CY - Basel ER -