TY - GEN A1 - Graf, Marcel A1 - Pippig, Robert A1 - Lehnert, Tim A1 - Jedynak, Angelika A1 - Härtel, Sebastian ED - Mocellin, Katia T1 - Aluminium-Matrix-Composites (AMC) for Hot Forged Components T2 - Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1 N2 - The development of new materials or material systems is always accompanied by the development of processing technologies suitable for the material. The reduction of process steps, the saving of material and the optimization of material properties are aims of forming processes. The basis for this is the comprehensive characterisation of the thermos-physical and thermos-mechanical technologically relevant material behaviour, taking into account the real process conditions. In the present work, the material-specific process limits were determined by means of experimental simulation and used in the numerical simulation in order, on the one hand, to identify the forming steps for optimizing the manufacturing conditions and, on the other hand, to be able to set the final material properties. It was essential to homogenize the casting microstructure for the forming processes and to adjust it to globulitical grains by solution annealing. The previously limited forming behaviour of the cast AlSi9Mg alloy with 20 vol.-% SiC could be increased thus to forging-relevant plastic strains without occurring damages. Based on the comprehensive temperature-dependent material data, a one-step and resource-efficient manufacturing process for AMC materials by hot forming could be developed with the help of the FE software Simufact Forming and validated in reality under near-industrial conditions. Y1 - 2023 SN - 978-3-031-41022-2 SN - 978-3-031-41023-9 U6 - https://doi.org/10.1007/978-3-031-41023-9_4 SN - 2195-4356 SP - 36 EP - 47 PB - Springer Nature Switzerland CY - Cham ER - TY - GEN A1 - Buhl, Johannes A1 - Härtel, Sebastian A1 - Besong, Lemopi Isidore ED - Mocellin, Katia T1 - Temperature Control of the Two-Point Incremental Forming Process to Achieve Homogeneous Martensite Content Based on Finite Element Simulations T2 - Proceedings of the 14th International Conference on the Technology of Plasticity - Current Trends in the Technology of Plasticity, ICTP 2023 - Volume 1 N2 - Deformation-induced martensite has been observed in the incremental sheet forming of metastable austenitic stainless steels (MASS). The presence of martensite improves the characteristics of the springs. Martensite transformation usually occurs at low temperatures (<70 ℃). Depending on the tool speed, incremental forming of disk springs requires between 3 to 5 min. The forming time needs to be short to increase the process output in industrial settings. However, accelerating the process leads to high temperatures above the martensite transformation temperature that suppress martensite formation, necessitating temperature control during forming. It is suggested to enhance the martensite content of the blank by cooling during the forming operation. In this contribution, two-point incremental sheet forming is conducted to determine the influence of process temperature on the phase content of MASS disk springs. A temperature-dependent phase change material model that includes the strain rate effect is implemented in finite element (FE) simulations to predict the martensite content. FE simulations are performed to investigate the convection coefficients and cooling time leading to process temperatures below 70 ℃. The framework can be used to control and speed up the incremental forming of disk springs while maintaining a high martensite content. Y1 - 2023 SN - 978-3-031-41022-2 SN - 978-3-031-41023-9 U6 - https://doi.org/10.1007/978-3-031-41023-9_74 SN - 2195-4356 SP - 739 EP - 747 PB - Springer CY - Cham ER - TY - GEN A1 - Szyndler, Joanna A1 - Härtel, Sebastian A1 - Bambach, Markus T1 - Machine learning of the dynamics of strain hardening based on contact transformations T2 - Journal of Intelligent Manufacturing N2 - Dislocation density-based models offer a physically grounded approach to modeling strain hardening in metal forming. Since these models are typically defined by Ordinary Differential Equations (ODEs), their accuracy is constrained by both, the model formulation and the parameter identification process. Machine Learning (ML) provides an alternative by allowing models to be constructed directly from experimental data, bypassing the accuracy limitations of explicitly defined models. However, applying ML to ODEs introduces the need for novel training techniques. This work presents a new approach for developing neural ODE models for flow curve description, utilizing a contact transformation to simplify the problem of learning an ODE into a learning a multivariate function. Y1 - 2025 UR - https://link.springer.com/article/10.1007/s10845-025-02577-6 U6 - https://doi.org/10.1007/s10845-025-02577-6 VL - 2025 PB - Springer ER - TY - GEN A1 - Grüger, Lennart A1 - Szyndler, Joanna A1 - Jensch, Felix A1 - Härtel, Sebastian T1 - Porosity analysis of L-PBF manufactured AZ91D components T2 - Materials research proceedings N2 - 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. KW - A91D KW - Additive Manufacturing KW - L-PBF KW - HIP KW - Process Parameter Analysis Y1 - 2025 SN - 978-1-64490-359-9 U6 - https://doi.org/10.21741/9781644903599-22 SN - 2474-395X VL - 54 SP - 199 EP - 208 PB - Materials Research Forum LLC CY - Millersville, PA 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 - Okolo, Chukwuemeka A1 - Eissing, Katharina A1 - Williams, Richard A1 - Jensch, Felix A1 - Fergani, Omar A1 - Härtel, Sebastian T1 - Investigation of the influence of AI-controlled process parameter adjustment on the mechanical properties of LBPF-manufactured parts T2 - Materials research proceedings N2 - 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. KW - LPBF-process KW - Machine learning KW - Mechanical properties Y1 - 2025 SN - 978-1-64490-359-9 U6 - https://doi.org/10.21741/9781644903599-24 SN - 2474-395X VL - 54 SP - 218 EP - 227 PB - Materials Research Forum LLC CY - Millersville, PA ER - TY - GEN A1 - Emdadi, Aliakbar A1 - Jensch, Felix A1 - Szyndler, Joanna A1 - Huang, Hsuan-Po A1 - Härtel, Sebastian A1 - Weiß, Sabine T1 - Void closure behavior during hot forming of an Fe-Al alloy T2 - Materials research proceedings N2 - 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. KW - Hot metal forming KW - Laser powder bed fusion (LPBF) KW - Post-processing KW - Void closure KW - X-Ray micro-computed tomography Y1 - 2025 SN - 978-1-64490-359-9 U6 - https://doi.org/10.21741/9781644903599-99 SN - 2474-395X VL - 54 SP - 927 EP - 935 PB - IWA Publishing CY - Millersville, PA ER - TY - GEN A1 - Ertugrul, Gökhan A1 - Emdadi, Aliakbar A1 - Jedynak, Angelika A1 - Weiß, Sabine A1 - Härtel, Sebastian T1 - Hot forming behavior of tungsten carbide reinforced Ni-based superalloy 625 additively manufactured by laser directed energy deposition T2 - Additive manufacturing letters N2 - The demands of high-performance industries such as aerospace, automotive, tool manufacturing, oil, and gas industries are driving the innovation in high-performance materials and their production methods. This study explores the impact of hybrid manufacturing, specifically the effect of the addition of tungsten carbide (WC/W2C) via Laser-Directed Energy Deposition (L-DED), on the hot workability, hardness, and microstructure of nickel-based superalloy Inconel 625 (IN625). IN625 is known for its high temperature and high corrosion resistance, and tungsten carbide for its high wear resistance and grain refinement effect. The integration of WC/W2C particles into the IN625 matrix, in addition to the use of the hybrid approach of additive manufacturing followed by a hot–forming process, significantly influences the microstructure and mechanical behavior of the material. Thus, while incorporation of the WC/W2C can strengthen the material and extend the mechanical limitations, its full impact, including any potential usages, should be thoroughly evaluated for the intended application of the materials. To understand the effect of WC/W2C, additive manufacturing of IN625 both with and without WC/W2C and isothermal hot compression was carried out. The objective is to analyze the differences in microstructure and properties between L-DED manufactured IN625, and WC-reinforced IN625, and their hot-forming behavior, focusing on the effects of WC addition and post-deformation on microstructure and mechanical properties. This work represents the first investigation into the effect of WC/W2C hard particles on the hot-forming process of additively manufactured Ni-based metal matrix composites. Y1 - 2025 U6 - https://doi.org/10.1016/j.addlet.2025.100267 SN - 2772-3690 VL - 13 SP - 1 EP - 12 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Ertugrul, Gökhan A1 - Emdadi, Aliakbar A1 - Härtel, Sebastian ED - MacDonald, Eric W. T1 - Powder production and additive manufacturing of iron aluminide alloys using plasma ultrasonic atomization and laser-directed energy deposition T2 - Additive manufacturing letters N2 - With a combination of desirable properties such as low density, high specific yield strength, low material cost, and excellent oxidation and corrosion resistance, iron aluminide (Fe-Al) has shown considerable potential to be an alternative to high-alloy chromium steels, and in some cases even nickel-based superalloys, in high-temperature applications. Due to these features, it is especially suitable for the aerospace and automotive industries. Recent advancements indicate an increasing interest in Fe-Al within the additive manufacturing industry, particularly in directed energy deposition (DED) processes. Despite this progress, processing of Fe-Al materials using the laser directed energy deposition (L-DED) has not been sufficiently investigated. In this study, Fe-Al powder material was produced from a commercial Al rod encased in a commercial low alloy-steel tube by a plasma-based ultrasonic atomization eliminating the need to cast an alloy ingot in advance. Subsequently, the produced powder was used in a l-DED process to fabricate an additively manufactured sample. The sample was investigated in terms of mechanical property, microstructure, chemical composition, and phase structure by scanning electron microscope (SEM) / energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and microhardness analyses. KW - Iron Aluminides (Fe-Al); Additive Manufacturing; Laser-Directed Energy Deposition (L-DED); Process Chain Plasma Ultrasonic Atomization; Powder; Intermetallic Phase Y1 - 2025 U6 - https://doi.org/10.1016/j.addlet.2025.100313 SN - 2772-3690 VL - 14 SP - 1 EP - 9 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Ertugrul, Gökhan A1 - Emdadi, Aliakbar A1 - Härtel, Sebastian T1 - Advancements in iron aluminide alloy processing : a comparative study with DED alternatives T2 - Materials research proceedings N2 - This article investigates the processing and characterization of iron aluminide lightweight alloy by plasma ultrasonic atomization and laser powder based directed energy deposition (DED-LB/p) and its comparison with other additive manufacturing alternatives. DED-LB/p provides precisely controllable process parameters, a wide range of feed materials supplied in powder form, a relatively high deposition rate and low heat input. These features favor the DED – LB/p process for novel materials such as iron aluminide. Thanks to a combination of desirable properties such as low density, high specific strength, low material cost, excellent oxidation resistance, and corrosion resistance, Fe-Al has established considerable potential to replace high-alloy chromium steels and, in some cases, even superalloys in high-temperature applications. In this study, Fe-Al alloy was first atomized into powder form from a commercial rod with core of aluminum and sleeve of a commercial low alloy-steel by plasma ultrasonic atomization. The resulting powder was then used for additive manufacturing with DED-LB/p in order to reduce cost and analyze the process chain. The results show that the use of powder produced by plasma ultrasonic atomization from commercial raw materials in the DED-LB/p process provides an effective combination for additive manufacturing of Fe-Al alloy and has some advantages over the alternative WAAM method. Y1 - 2025 U6 - https://doi.org/10.21741/9781644903599-28 SN - 2474-395X VL - 54 SP - 254 EP - 263 PB - Materials Research Forum LLC CY - Millersville, PA ER - TY - GEN A1 - Ertugrul, Gökhan A1 - Hälsig, Andre A1 - Rimpl, Robert A1 - Hensel, Jonas A1 - Härtel, Sebastian T1 - Artificial neural network based calibration of Goldak heat source parameters in tandem plasma transferred arc process using finite element analysis T2 - The international journal of advanced manufacturing technology N2 - The paper proposes a novel approach for determining multiple heat source parameters to achieve the necessary accuracy in the numerical prediction for a parallel tandem plasma transferred arc process. An artificial neural network (ANN) approach as a supervised learning–based artificial intelligence (AI) was used to model the complex relationship between heat distribution and tandem/dual heat source parameters based on finite element analysis (FEA). This study presents the first ANN-assisted numerical simulation for multiple heat source optimization of the tandem plasma transferred arc process. The model demonstrated high accuracy in predicting and calibrating the tandem heat source parameters, based on systematic simulation trials of the tandem plasma transferred arc welding. The results of the tandem heat source determined by ANN-assisted FEA were verified using experimental data on melt pool size and substrate distortion. This verification considered metrics such as penetration width, penetration depth, melt pool length, melt pool half-width, and the absolute distortion (measured as the difference between minimum and maximum displacement), with relative errors of 7.0%, 7.6%, 0.4%, 1.9%, and 9.7%, respectively. Y1 - 2025 U6 - https://doi.org/10.1007/s00170-025-15843-x SN - 0268-3768 VL - 139 SP - 2349 EP - 2363 PB - Springer Nature CY - London ER - TY - GEN A1 - Jiang, Yuyao A1 - Knaack, Marcus A1 - Martin, Clas Aljoscha A1 - Tost, Frank A1 - Alimov, Artem A1 - Härtel, Sebastian A1 - Gardill, Markus T1 - A 120 GHz industrial radar sensor network for condition monitoring of a forging process T2 - IEEE sensors journal N2 - Current trends in forging technology emphasize increased automation and a rising demand for high-precision components. Among the key factors influencing the forging quality are process parameters, which also serve as indispensable inputs for data-driven modeling. This necessitates the establishment of a stable and robust sensor network to enable high-quality process monitoring. This study investigates the implementation of a heterogeneous sensor network within an energy-bound forging press, integrating industrial 120 GHz radar sensors for comprehensive data collection. A complete radar signal processing chain is developed, encompassing signal acquisition, pre-processing, and state estimation of the press ram. The validation against conventional reference sensors confirms the reliability and accuracy of the radar-based measurements. The results demonstrate the feasibility of the radar employment in the complex forging environment. KW - Sensor network KW - FMCW radar KW - Kalman filter KW - Process parameter KW - Condition monitoring KW - Hot forging Y1 - 2025 U6 - https://doi.org/10.1109/JSEN.2025.3636060 SN - 1558-1748 SP - 1 EP - 10 PB - IEEE CY - Piscataway, NJ 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 - TY - GEN A1 - Jensch, Felix A1 - Sviridov, Alexander A1 - Dubinin, Sergej A1 - Karabulut, Fatih A1 - Weiß, Sabine A1 - Härtel, Sebastian T1 - Parameter optimization for low-porosity Ti-6Al-4V parts produced using accelerated PBF-LB process T2 - Progress in additive manufacturing N2 - 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. KW - Laser powder bed fusion KW - Process parameter optimization KW - Porosity analysis KW - Ti-6Al-4V KW - Additive manufacturing productivity Y1 - 2026 U6 - https://doi.org/10.1007/s40964-025-01510-w SN - 2363-9520 SP - 1 EP - 17 PB - Springer CY - Cham ER -