TY - JOUR A1 - Spranger, Felix A1 - Schirdewahn, S. A1 - Kromm, Arne A1 - Merklein, M. A1 - Hilgenberg, Kai T1 - On the influence of TiB2, TiC, and TiN hard particles on the microstructure of localized laser dispersed AISI D2 tool steel surfaces N2 - The control of friction and wear is a major concern in many industrial applications. A promising method for tailored surface modification is the so-called laser implantation technique. This method combines surface texturing and material optimization in one processing step by a localized dispersing of hard ceramic particles using pulsed laser radiation. Wear resistant, protruding micrometric features (implants) with defined geometry can be created in a deterministic pattern where needed on highly stressed surfaces, i.e., on forming or cutting tools. However, in order to maintain the implants over the tool’s lifetime, a suitable selection of hard ceramic particles is a prerequisite. They must provide a defect-free metal matrix composite with a high share of homogeneously distributed particles and, especially, high implant hardness. In this study, TiN, TiC, and TiB2 hard particles were compared as implant materials for the first time. By a systematic variation of pulse power and pulse duration, their dispersing behavior and influence on the material properties of AISI D2 tool steel were investigated. Although all powder materials had grain sizes smaller than 10 μm, it was possible to disperse them by pulsed laser radiation and to obtain defect-free protruding implants. The highest share of dispersed particles (∼64%) was observed for TiB2. By scanning electron microscopy and energy dispersive x-ray spectroscopy, it was also shown that a significant share of the preplaced particles was dissolved by the laser beam and precipitated as nanometer sized particles within the matrix during solidification. These in situ formed particles have a decisive influence on the material properties. While the TiN and TiC implants have shown maximum hardness values of 750 and 850 HV1, the TiB2 implants have shown the highest hardness values with more than 1600 HV1. By x-ray diffraction, it was possible to ascribe the lower hardness values of TiC and TiN implants to high amounts of retained austenite in the metal matrix. By implanting TiB2, the formation of retained austenite was successfully suppressed due to the in situ formation of TiC particles, which was proven by electron backscatter diffraction. In conclusion, all the implant materials are basically suitable for laser implantation on AISI D2 tool steel. However, TiB2 has shown the most promising results. T2 - ICALEO 2019 CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser implantation KW - Surface texturing KW - AISI D2 KW - TiB2 KW - TiN KW - TiC KW - Retained Austenite KW - Localized laser dispersing PY - 2020 DO - https://doi.org/10.2351/7.0000059 VL - 32 IS - 2 SP - 022028 EP - 022028-9 PB - AIP Publishing AN - OPUS4-50712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schirdewahn, S. A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Merklein, M. T1 - Localized Laser Dispersing of Titanium-Based Particles for Improving the Tribological Performance of Hot Stamping Tools N2 - Within the scope of this work, a new surface engineering technology named laser implantation has been investigated, in order to improve the tribological performance of hot stamping tools. This technique is based on manufacturing highly wear-resistant, separated, and elevated microfeatures by embedding hard ceramic particles into the tool surface via pulsed laser radiation. Hence, the topography and material properties of the tool are modified, which influences the thermal and tribological interactions at the blank-die interface. To verify these assumptions and to clarify the cause–effect relations, different titanium-based particles (TiB2, TiC, TiN) were laser-implanted and subsequently analyzed regarding to their geometrical shape and mechanical properties. Afterwards, quenching tests as well as tribological experiments were carried out by using titanium-diboride as the most promising implantation material for reducing the tribological load due to high hardness value of the generated implants. Compared to conventional tooling systems, the modified tool surfaces revealed a significantly higher wear resistance as well as reduced friction forces while offering the possibility to adjust the thermal interactions at the blank-die interface. Based on these results, a tailored tool surface modification can be pursued in future research work, in order to enhance the effectiveness of the hot stamping technology. KW - Hot stamping KW - Tribology KW - Surface modification KW - Localized laser dispersing PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510981 DO - https://doi.org/10.3390/jmmp4030068 VL - 4 IS - 3 SP - 68 PB - MDPI AN - OPUS4-51098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schirdewahn, S. A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Merklein, M. T1 - Localized dispersing of TiB2 and TiN particles via pulsed laser radiation for improving the tribological performance of hot stamping tools N2 - The aim of this study is to increase the tribological performance of hot stamping tools by using a laser implantation process. This technique allows the fabrication of separated, elevated and dome-shaped microfeatures on the tool surface in consequence of a localized dispersing of ceramic particles via pulsed laser radiation. Hence, the topography and material properties of the tool are modified, which influences the tribological interactions at the blank-die interface. However, an appropriate selection of ceramic particles is an essential prerequisite, in order to obtain tailored and highly wear resistant surface features. In this regard, different titanium-based hard particles (TiB2 and TiN) were laser-implanted on hot working tool specimens and subsequently tested by means of a modified pin-on-disk test regarding to their wear and friction behavior. KW - Surface modification KW - Tribology KW - Laser implantation KW - Hot working tool steel KW - Hot stamping PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514171 DO - https://doi.org/10.1016/j.procir.2020.09.069 VL - 94 SP - 901 EP - 904 PB - Elsevier B.V. AN - OPUS4-51417 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heßmann, Jennifer A1 - Bachmann, Marcel A1 - Hilgenberg, Kai T1 - Numerical and experimental investigation of controlled weld pool displacement by electromagnetic forces for joining dissimilar materials N2 - In order to reduce CO2 emissions, an increasing interest in lightweight construction exists in the automotive industry, especially the multi-material-design approach. The main construction materials here are steels and aluminium alloys. Due to their different physical material properties and limited mutual solubility, these two materials cannot be joined thermally without difficulty. This paper presents a new joining approach for dissimilar materials. It uses electromagnetic displacement of a laser-generated melt pool to produce overlap joints between 1 mm steel (1.0330) and 2 mm aluminium alloy (EN AW 5754). Contactless induced Lorentz forces are generated by an alternating current (AC) magnet system. The controlled displacement of the aluminium alloy melt into the hole of the overlying steel sheet is investigated through numerical and experimental studies. The numerical results are compared with cross sections and thermocouple measurements. For the first time, it is possible to achieve a reproducible controlled melt pool displacement on thin sheets to produce overlap joints between dissimilar materials. KW - Displacement KW - Laser beam welding KW - Dissimilar materials KW - Joining technology KW - Electromagnetic field KW - Lorentz force KW - Numerical investigation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516640 DO - https://doi.org/10.3390/met10111447 VL - 10 IS - 11 SP - 1447 EP - 1462 PB - MDPI CY - Basel, Schweiz AN - OPUS4-51664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schridewahn, S. A1 - Spranger, F. A1 - Hilgenberg, Kai A1 - Merklein, M. T1 - Laser Implantation of Niobium and Titanium-Based Particles on Hot Working Tool Surfaces for Improving the Tribological Performance within Hot Stamping N2 - Within the scope of this work, a laser implantation process has been used, in order to improve the tribological performance of hot stamping tools. This surface engineering Technology enables the generation of dome-shaped, elevated and highly wear resistant microfeatures on tool surfaces in consequence of a localized dispersing of hard ceramic particles via pulsed laser radiation. As a result, the topography and material properties of the tool and thus the tribological interactions at the blank-die interface are locally influenced. However, a suitable selection of hard ceramic particles is imperative for generating defect-free surface features with a high share of homogenously disturbed particles. For this purpose, different niobium (NbB2 and NbC) as well as titanium-based (TiB2 and TiC) materials were embedded on hot working tool specimens and subsequently analyzed with regard to their resulting shape and mechanical properties. Afterwards, modified pin-on-disk tests were carried out by using conventional and laser-implanted tool surfaces, in order to evaluate the wear and friction behavior of both tooling systems. KW - Surface modification KW - Triobology KW - Laser implantation PY - 2020 DO - https://doi.org/10.4028/www.scientific.net/DDF.404.117 SN - 1662-9507, VL - 404 SP - 117 EP - 123 PB - Trans Tech Publications Ltd. AN - OPUS4-53690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schridewahn, S. A1 - Spranger, F. A1 - Hilgenberg, Kai A1 - Merklein, M. T1 - Verbesserung des tribologischen Einsatzverhaltens von Presshärtewerkzeugen durch Laserimplantation titanbasierter Hartstoffpartikel N2 - In der Automobilindustrie stellt das Presshärteverfahren eine Schlüsseltechnologie zur ressourceneffizienten Herstellung sicherheitsrelevanter Karosserie-komponenten dar. Während der Umformoperation treten jedoch hohe Reibungs- und Verschleißerscheinungen an den interagierenden Werkzeug- und Werkstückwirkflächen auf, die sowohl die Bauteilqualität als auch die Maschinenstandzeit nachhaltig beeinträchtigen. Um die bestehenden Verfahrensgrenzen zu erweitern, wird daher eine Modifikation der Presshärtewerkzeuge mittels Laserimplantation angestrebt. Hierbei werden in die Werkzeugoberfläche keramische Hartstoffpartikel anhand eines gepulsten Laserstrahles eingebettet, infolgedessen kuppelförmige sowie höchstfeste Strukturen im Mikrometerbereich entstehen. Die Auswahl geeigneter Hartstoffmaterialien stellt jedoch ein entscheidendes und bisweilen limitierendes Kriterium dar, um defektfreie sowie verschleißresistente Oberflächenmodifikationen zu generieren. In diesem Zusammenhang wurden im Rahmen dieser Arbeit unterschiedliche titanbasierte Hartstoffpartikel auf presshärtespezifische Werkzeugstähle laserimplantiert und anschließend mittels modifizierten Pin-on-Disk-Tests hinsichtlich ihres tribologischen Einsatzverhaltens untersucht. Um die Wirksamkeit des Laserimplantationsverfahrens zu evaluieren, wurden zudem Verschleißuntersuchungen an unmodifizierten Werkzeugoberflächen durchgeführt und mit den erzielten Ergebnissen der lokal dispergierten Topographien verglichen. T2 - 15. Erlanger Workshop Warmblechumformung 2020 CY - Erlangen, Germany DA - 17.11.2020 KW - Laserimplantation KW - Werkzeugmodifikation KW - Presshärten KW - Tribologie PY - 2020 SP - 1 AN - OPUS4-53692 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heßmann, Jennifer A1 - Hilgenberg, Kai T1 - Prozesssimulation elektromagnetischer Kräfte zum Fügen artungleicher Werkstoffe N2 - Prozesssimulation zur Eingrenzung der elektromagnetischen Kräfte zum gezielten Verdrängen einer laserstrahlinduzierten Schmelze zum Fügen artungleicher Materialien. Berechnung der Lorentzkraftverteilung im Schmelzbad. Abschätzung der Temperaturentwicklung beim Verdrängungsprozess. T2 - Assistentenseminar der WGF 2020 CY - Online meeting DA - 01.09.2020 KW - Stahl und Aluminium KW - Artungleiche Werkstoffe KW - Elektromagnetische Schmelzbadbeeinflussung KW - Fügetechnologie KW - Laserstrahlschweißen PY - 2020 SN - 978-3-96144-141-9 VL - 370 SP - 51 EP - 60 PB - DVS Media GmbH AN - OPUS4-53927 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Additive Manufacturing: Opportunities and challenges for NDT N2 - Additive manufacturing processes are increasingly being used in industrial applications. Especially powder bed fusion processes are of high interest due to their capability to economically produce individual, highly complex and functionally integrated components in small batches. However, the quality assurance of these components remains a challenge. Internal defects and undesirable microstructures and surface conditions can deteriorate the mechanical properties. Especially for use in safety-relevant applications, new design and inspection concepts are needed that take these factors into account. This talk presents typical defects and microstructure phenomena resulting from the laser powder bed fusion process and identifies challenges and opportunities for non-destructive testing from a manufacturing engineering perspective. In particular, the possibility of a process-integrated quality control is shown based on current research results. T2 - The 13th International Symposium on NDT in Aerospace 2021 CY - Online meeting DA - 05.10.2021 KW - Additive manufacturing KW - Laser powder bed fusion KW - In-situ monitoring PY - 2021 AN - OPUS4-53484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kempf, A. A1 - Hilgenberg, Kai T1 - Influence of heat treatments on AlSi10Mg specimens manufactured with different laser powder bed fusion machines N2 - Mechanical properties such as ultimate tensile strength, yield strength, and tensile elongation of parts manufactured with Laser Powder Bed Fusion (L-PBF) can differ significantly after the building process limiting the advantage of production flexibility of that technology. At this background, the present work investigated the influence of post process heat treatments (HT) on microstructure, hardness, and tensile properties of AlSi10Mg specimens in different As-built (AB) conditions. For this purpose, two superordinate aspects were covered within this study. Firstly, various HTs were performed on specimens built-up with the same L-PBF machine applying the same parameter set-up. Results of tensile tests and hardness measurements were discussed considering the microstructural changes examined with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy as well as X-ray diffraction, and gathered in a material data map. Based on the observed microstructural changes and a calculated quality index which comprises strength and ductility properties, three HTs were selected for the second part of this work. Therein, the effect of these HTs on specimens fabricated with overall three L-PBF machines working with different raw materials, process parameters, and build-up strategies was studied. Specimens characterization included porosity measurements, the evaluation of material defects, microstructure analysis via SEM, hardness measurements, and tensile tests. It was found that strength properties in the AB condition revealed appreciable deviations: Values of yield strength and ultimate tensile strength were from 228 to 292 MPa and from 346 to 484 MPa, respectively. Whereas heat treated specimens at 300 °C for 0.5 as well as 2 h only exhibited slight differences in strength, a complete homogenization of strength properties was obtained after conducting a T6 HT. Nevertheless, ductility was not homogenized after heat treating caused by the presence of material defects such as keyhole pores and lack of fusion defects. It was shown that even slight differences in porosity determined in cross-sections can significantly affect ductility properties. KW - Laser powder bed fusion PY - 2021 DO - https://doi.org/10.1016/j.msea.2021.141371 SN - 0921-5093 VL - 818 SP - 141371 PB - Elsevier B.V. CY - Berlin AN - OPUS4-52741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heßmann, Jennifer A1 - Bachmann, Marcel A1 - Hilgenberg, Kai T1 - Joining dissimilar materials a new approach based on laser beam welding and melt displacement by electromagnetic forces N2 - In order to reduce weight of vehicles, the interest in multi-material-design has been growing within the last few years. For vehicles the combination of steel and aluminium alloys offers the most promising compromise between weight, strength and formability. Thermal joining of these dissimilar materials is still a challenge to overcome. A possible approach is a new joining technology, whereby a combination of laser beam welding and contactless induced electromagnetic forces are used to displace the generated melt of one joining partner into a notch of the other. This paper presents the working principle and shows numerical analyses to improve the understanding of this joining process. The simulations help to calculate the thermal development of the joining partners, which is important for the formation of intermetallic phases. Furthermore, the calculation of the time required for a complete displacement is possible. The numerical results are validated by experimental results. T2 - LiM 2021 CY - Online meeting DA - 21.06.2021 KW - Joining dissimilar materials KW - Laser beam welding KW - Electromagnetic forces KW - Steel and aluminium PY - 2021 SP - 1 EP - 9 PB - Wissenschaftliche Gesellschaft Lasertechnik e.V. (WLT) AN - OPUS4-52978 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heßmann, Jennifer A1 - Hilgenberg, Kai A1 - Bachmann, Marcel T1 - An electromagnetic approach to dissimilar metal welding N2 - To save weight without affecting the functional properties of vehicles, heavy materials must be replaced with lighter alternatives.Modern lightweight concepts have therefore been developed, featuring multi-material designs that require the joining of dissimilar materials.One new possible approach for the joining of dissimilar metals is based on laser welding and melt displacement by contactless induced electromagnetic forces. KW - Joining dissimilar materials KW - Laser beam welding KW - Electromagnetic forces KW - Steel and aluminium PY - 2021 SP - 1 EP - 5 AN - OPUS4-53373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schirdewahn, S. A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Merklein, M. T1 - Investigation of the thermal and tribological performance of localized laser dispersed tool surfaces under hot stamping conditions N2 - In the automotive industry, hot stamping has been established as a key technology for manufacturing safety-relevant car body components with high strength-to-weight ratio. However, hot stamping tools are stressed by cyclic thermo-mechanical loads, which leads to severe wear and high friction during the forming operation. Consequently, the quality of the parts, the durability of the tools and the efficiency of the process are negatively affected. Within the scope of this work, a promising approach named laser implantation process has been investigated for improving the tribological behavior of hot stamping tools. This technique enables the fabrication of highly wear resistant, separated and elevated micro-features by embedding hard ceramic particles into the tool via pulsed laser radiation. Hence, highly stressed tool areas can be modified, which influences the thermal and tribological interactions at the blank-die interface. To clarify these cause-effect relations, numerical simulations, quenching tests as well as tribological investigations have been conducted. In this context, laser-implanted tools reveal a significantly improved tribological performance while offering the possibility to adjust the thermal properties within hot stamping. Based on these results, a tailored tool modification can be pursued in future research work, in order to enhance the effectiveness of hot stamping tooling systems. KW - Hot stamping KW - Laser Implantation KW - Surface structuring KW - Wear KW - Friction PY - 2021 DO - https://doi.org/10.1016/j.wear.2021.203694 VL - 476 SP - 1 EP - 11 PB - Elsevier B.V. AN - OPUS4-52988 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kempf, Andreas A1 - Kruse, Julius A1 - Madia, Mauro A1 - Hilgenberg, Kai T1 - Correlation between quasistatic und fatigue properties of additively manufactured AlSi10Mg using Laser Powder Bed Fusion N2 - In order to find a resource efficient approach for the fatigue lifetime prediction of laser powder bed fusion (L-PBF) processed AlSi10Mg material, results of tensile and fatigue tests were compared. The specimens were manufactured with three different L-PBF machines and studied in different heat treatment conditions (as-built, annealed, T6 heat treated). The investigations showed that the high attainable tensile strength properties after the manufacturing process are not beneficial in the high cycle fatigue (HCF) regime. In contrast, the applied heat treatments, which lead typically to a decrease of ultimate tensile strength, improved dramatically the fatigue behavior. Additionally, a clear correlation between the elongation at fracture and HCF resistance has been found for individual heat treatment conditions. This empiric relationship provides an estimation of the fatigue resistance in the presence of material defects and can be implemented in part and process approvals. T2 - FATIGUE DESIGN 2021 CY - Online meeting DA - 17.11.2021 KW - Additive Manufacturing KW - Laser powder bed fusion KW - AlSi10Mg KW - Tensile properties KW - Fatigue properties PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544921 DO - https://doi.org/10.1016/j.prostr.2022.03.009 SN - 2452-3216 VL - 38 SP - 77 EP - 83 PB - Elsevier B.V. AN - OPUS4-54492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schirdewahn, S. A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Merklein, M. T1 - Tribological and thermal behavior of laser implanted tool surfaces for hot stamping AlSi coated 22MnB5 sheets N2 - In the automotive industry, the development of electrically powered vehicles has become a major forward-looking topic. For improving the range and thus the efficiency of electric cars, lightweight construction has gained even more importance. In this regard, hot stamping has been established as a suitable and resource efficient process to manufacture high-strength and lightweight body-in-white components. This method combines hot forming and quenching of boron-manganese steel 22MnB5 in a single process step. As a result, complex structures with thin sheet thicknesses and high ultimate tensile strength up to 1500 MPa are generated. However, the use of lubricants is not possible at elevated temperatures, which subsequently leads to high thermo-mechanical tool stresses. As a side effect, high friction and severe wear occur during the forming process, which affect the resulting part quality and maximum tool life. Therefore, the aim of this study is to improve the tribological performance of hot stamping tools by using a laser implantation process. This technique is based on manufacturing highly wear resistant, separated and elevated structures in micrometer range by embedding hard ceramic particles into the tool material via pulsed laser radiation. As a result, highly stressed areas on the tool surface can be modified locally, which in turn influence the tribological and thermal behavior during the forming process. In this regard, laser implanted and conventionally tool surfaces were investigated under hot stamping conditions. A modified pin-on-disk test was used to analyze the friction coefficient and occuring wear mechanisms. Furthermore, quenching tests as well as hardness measurements were carried out to gain in-depth knowledge about the cooling behavior of the modified tool surfaces and its impact to the resulting mechanical part properties. KW - Laser implantation KW - Laser dispersing KW - Surface structuring KW - Hot stamping PY - 2022 DO - https://doi.org/10.4028/p-e4i60t SN - 1662-9507 IS - 414 SP - 69 EP - 74 PB - Trans Tech Publications CY - Baech AN - OPUS4-54302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heßmann, Jennifer A1 - Hilgenberg, Kai ED - Hausmann, J. M. T1 - Meeting the challenge of thermal joining of steel and aluminum using a new approach based on melt displacement by electromagnetic forces N2 - Environmental protection, resource conservation and CO2 reduction require new joining concepts for effective multi-material design in automotive lightweight construction. The thermal joining of dissimilar materials, especially the combination of aluminum alloys and steel, is associated with difficulties. Different material properties, such as melting point and coefficient of thermal expansion, complicate joining processes. Furthermore, the insolubility between these materials results in the formation of intermetallic phases. These brittle phases reduce the load-bearing capacity and quality of the joints. The thickness of the intermetallic phases should not reach the critical value of 10 μm to ensure good mechanical properties of the joint. It is known that a two-phase reaction layer consisting of Al5Fe2 and Al3Fe (also known as Al13Fe4) forms at the interface between solid steel and liquid aluminum. Due to high cooling rates, as it is the case in laser beam welding, metastable intermetallic compounds can form different from the equilibrium state. The formation of the intermetallic reaction layer is a diffusion-controlled process. So, it is only possible to control the growth of these phases. This problem has led to use joining methods that do not require the melting of both joining partners. A promising joining method is laser beam welding-brazing, whereby only one joining partner is melted and wets the solid joining partner. Conventional laser beam welding-brazing only results in material-fit joints and often requires the use of expensive filler materials. An additional form-fit could optimize the mechanical performance of the joint. For this reason, a new joining method for overlap configurations of dissimilar materials was developed. A laser beam melts the lower joining partner through a cavity of the upper joining partner. The created melt pool is moved upwards into the cavity of the upper joining partner due to contactless induced Lorentz forces of an AC-magnetic system. The displaced melt creates a form- and material-fit joint after solidification. The advantage of this joining technology is the absence of filler materials, flux agents and expensive auxiliary joining elements. T2 - 5th International Conference Hybrid 2022 - Materials and Structures CY - Leoben, Austria DA - 20.07.2022 KW - Joining dissimilar materials KW - Laser beam welding KW - Electromagnetic forces KW - Steel and aluminium PY - 2022 SN - 978-3-88355-426-6 SP - 6 EP - 8 PB - Deutsche Gesellschaft für Materialkunde (DGM) CY - Sankt Augustin AN - OPUS4-55536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Additive Fertigungsverfahren und Defekte N2 - Überblick über die derzeitig wichtigsten additiven Fertigungsverfahren für metallische Werkstoffe in der Industrie (PBF, DED, BJT) und Berücksichtigung der wesentlichen Prozessmerkmale und Nachbearbeitungsschritte. Vorstellung der wichtigsten Defektphänomene und Nennung von Ursachen und Abhilfemaßnahmen. T2 - BAM Akademie: Qualitätssicherung in der additiven Fertigung CY - Online meeting DA - 14.09.023 KW - Additive Fertigung KW - Defekte KW - Überblick PY - 2023 AN - OPUS4-58302 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drendel, Jan A1 - Logvinov, Ruslan A1 - Heinrichsdorff, Frank A1 - Hilgenberg, Kai T1 - Simulation-based controlling of local surface temperature in laser powder bed fusion using the process laser N2 - State-of-the-art laser powder bed fusion (PBF-LB/M) machines allow pre-heating of the substrate plate to reduce stress and improve part quality. However, two major issues have been shown in the past: First, with increasing build height the apparent pre-heat temperature at the surface can deviate drastically from the nominal pre-heat temperature in the substrate plate. Second, even within a single layer the local surface pre-heat temperature can show large gradients due to thermal bottlenecks in the part geometry underneath the top surface. Both lead to unwanted changes in microstructure or defects in the final parts. In this study, a first attempt is taken to show the feasibility of pre-heating the top surface with the onboard laser beam to overcome the mentioned issues. A single layer of a group of three parts built from IN718 to a height of 33.5 mm is pre-heated in a commercially available PBF-LB/M machine to an average steady state surface temperature of 200 °C using the onboard laser beam. The parts are continuously heated, omitting powder deposition and melting step. Temperatures are measured by thermocouples underneath the surface. The experiments are supported by a thermal finite element (FE) model that predicts the temperature field in the parts. When heating the parts uniformly with the laser beam, differences in surface temperatures as large as 170 K are observed. To overcome this inhomogeneity, the heat flux supplied by the laser beam is modulated. An optimized, spatial heat flow distribution is provided by the thermal FE model and translated into a scan pattern that reproduces the optimized heat distribution on the PBF-LB/M machine by locally modulating hatch distance and scan velocity. This successfully reduces the differences in surface temperature to 20 K. Thermographic imaging shows that a homogeneous surface temperature can be achieved despite the localized heat input by the beam. The potential for industrial application of the optimized laser-heating technique is discussed. KW - Additive Manufacturing KW - Simulation KW - Surface temperature KW - Laser powder bed fusion PY - 2023 DO - https://doi.org/10.1016/j.addma.2023.103854 SN - 2214-8604 VL - 78 SP - 1 EP - 16 PB - Elsevier B.V. AN - OPUS4-58825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Eine digitale QI für die moderne Produktion: Digital Quality Assurance in der Additiven Fertigung N2 - Der Vortragt stellt den Use Case Additive Fertigung und das zugehörige Reallabor in QI Digital in Kürze vor und zeigt, mit welchen digitalen Tools das Reallabor mit der übergeordneten Plattform QualityX Daten austauscht. T2 - QI Forum 2023 CY - Berlin, Germany DA - 10.10.2023 KW - Additive Fertigung KW - Digitale Qualitätssicherung KW - QI Digital PY - 2023 AN - OPUS4-58830 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epperlein, Martin A1 - Hilgenberg, Kai A1 - Hellfritz, Benjamin A1 - Löffler, Frank T1 - Digitisation of the quality infrastructure - using the example of additive manufacturing N2 - Rapidly advancing technologies and progressive digitisation are posing challenges to the established quality infrastructure (QI). In response, the key stakeholders of the German QI established the initiative QI-Digital aimed at developing new solutions for modern quality assurance. One of the central use cases herein is quality assurance for additive manufacturing, in which a fully interlinked additive manufacturing process chain is established. The intention is to collect and process data from each production step, allowing for a comprehensive digital view of the physical material flow. Within this process chain, prototypes of digital QI tools like machine readable standards and digital quality certificates are being demonstrated, tested, and evolved. This is complemented by research on the process level, comprising the evaluation and refinement of methods for in-situ and ex-situ quality assurance, as well as algorithms for registration, reduction, and analysis of process data. This paper presents the status, goals, and vision for the QI-Digital use case additive manufacturing. T2 - Metal Additive Manufacturing Conference 2023 CY - Wien, Austria DA - 17.10.2023 KW - Additive Manufacturing KW - Digitalisation KW - Quality Assurance PY - 2023 SP - 96 EP - 104 CY - Wien AN - OPUS4-58628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Poka, Konstantin A1 - Merz, Benjamin A1 - Epperlein, Martin A1 - Hilgenberg, Kai T1 - Integration of the whole digital chain in a unique file for PBF-LB/M: practical implementation within a digital thread and its advantages N2 - The industrialization of AM is only possible by creating synergy with the tools of Industry 4.0. The system technology of Powder Bed Fusion with Laser beam of Metals (PBF-LB/M) reached a level of high performance in terms of process stability and material spectrum in the past years. However, the digital process chain, starting from CAD via CAM and plant-specific compila-tion of the manufacturing file exhibits media disruptions. The consequence is a loss of metadata. A uniform data scheme of simulation for Design for Additive Manufacturing (DfAM), the PBF-LB/M process itself and quality assurance is currently not realized within industry. There is no entity in the common data flows of the process chains, that enables the integration of these functionalities. As part of the creation of a digital quality infrastructure in the QI-Digital pro-ject, an integration of the CAD/CAM chain is being established. The outcome is a file in an advanced commercially available format which includes all simula-tions and manufacturing instructions. The information depth of this file extends to the level of the scan vectors and allows the automatic optimization and holis-tic documentation. In addition, the KPI for the economic analysis are generated by compressing information into a unique file combined with the application of a digital twin. The implementation and advantages of this solution are demon-strated in a case study on a multi-laser PBF-LB/M system. A build job contain-ing a challenging geometry is thermally simulated, optimized, and manufac-tured. To verify its suitability for an Additive Manufacturing Service Platform (AMSP), the identical production file is transferred to a PBF-LB/M system of another manufacturer. Finally, the achieved quality level of the build job is evaluated via 3D scanning. This evaluation is carried out in the identical entity of the production file to highlight the versatility of this format and to integrate quality assurance data. T2 - Additive Manufacturing for Products and Applications 2023 CY - Lucerne, Switzerland DA - 11.09.2023 KW - Laser Powder Bed Fusion KW - Digital Twin KW - Data Integrity KW - Process Chain Integration KW - Computer Aided Manufacturing PY - 2023 SN - 978-3-031-42982-8 DO - https://doi.org/10.1007/978-3-031-42983-5_7 SN - 2730-9576 VL - 3 SP - 91 EP - 114 PB - Springer CY - Cham AN - OPUS4-58363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheuschner, Nils A1 - Heinrichsdorff, F. A1 - Oster, Simon A1 - Uhlmann, E. A1 - Polte, J. A1 - Gordei, A. A1 - Hilgenberg, Kai T1 - In-situ monitoring of the laser powder bed fusion process by thermography, optical tomography and melt pool monitoring for defect detection N2 - For the wide acceptance of the use of additive manufacturing (AM), it is required to provide reliable testing methods to ensure the safety of the additively manufactured parts. A possible solution could be the deployment of in-situ monitoring during the build process. However, for laser powder bed fusion using metal powders (PBF-LB/M) only a few in-situ monitoring techniques are commercially available (optical tomography, melt pool monitoring), which have not been researched to an extent that allows to guarantee the adherence to strict quality and safety standards. In this contribution, we present results of a study of PBF-LB/M printed parts made of the nickel-based superalloy Haynes 282. The formation of defects was provoked by local variations of the process parameters and monitored by thermography, optical tomography and melt pool monitoring. Afterwards, the defects were characterized by computed tomography (CT) to identify the detection limits of the used in-situ techniques. T2 - Lasers in Manufacturing Conference 2023 CY - Munich, Germany DA - 26.06.2023 KW - Thermography KW - Optical tomography KW - Melt-pool-monitoring KW - Laser powder bed fusion KW - Haynes 282 KW - Additive Manufacturing PY - 2023 UR - https://www.wlt.de/lim2023-proceedings/system-engineering-and-process-control SP - 1 EP - 10 AN - OPUS4-58466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, M. A1 - Schlingmann, T. A1 - Schmidt, J. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Klöden, B. T1 - A Round Robin Test To Investigate The Printing Quality Of PBF LB/M Processed AlSi10Mg N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail. T2 - World PM2022 CY - Lyon, France DA - 09.10.2022 KW - Additive manufacturing KW - AlSi10Mg KW - Laser powder bed fusion KW - Round robin KW - Reproducibility PY - 2022 AN - OPUS4-56303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, M. A1 - Schlingmann, T. A1 - Schmidt, J. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Klöden, B. T1 - A Round Robin Test To Investigate The Printing Quality Of PBF-LB/M Processed AlSi10Mg N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail. T2 - World PM2022 CY - Lyon, France DA - 09.10.2022 KW - Additive manufacturing KW - Round robin KW - Reproducibility KW - Laser powder bed fusion KW - AlSi10Mg PY - 2022 SN - 978-1-899072-54-5 SP - 1 EP - 10 PB - European Powder Metallurgy Association (EPMA) AN - OPUS4-56304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Additive Fertigungsverfahren und Defekte N2 - Überblick über die derzeitig wichtigsten additiven Fertigungsverfahren für metallische Werkstoffe in der Industrie (PBF, DED, BJT) und Berücksichtigung der wesentlichen Prozessmerkmale und Nachbearbeitungsschritte. Vorstellung der wichtigsten Defektphänomene und Nennung von Ursachen und Abhilfemaßnahmen. T2 - BAM Akademie: Qualitätssicherung in der additiven Fertigung CY - Online meeting DA - 17.09.2024 KW - Additive Fertigung KW - Defekte KW - Überblick PY - 2024 AN - OPUS4-61172 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heßmann, Jennifer A1 - Hilgenberg, Kai T1 - New approach for multi-material design: Combination of laser beam and electromagnetic melt pool displacement by induced Lorentz forces N2 - Multimaterial structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam, and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatially uncoupled from the influence of keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction and EDX analysis. The detected intermetallic phases consist of a 5–6 μm compact phase seam of Al5.6Fe2 and a needle-shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN. KW - Electromagnetic forces KW - Joining dissimilar materials KW - Laser beam welding KW - Steel and aluminium KW - Lorentz forces PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564840 DO - https://doi.org/10.2351/7.0000763 SN - 1042-346X VL - 35 IS - 1 SP - 1 EP - 8 PB - Laser Institute of America CY - Orlando, Fla. AN - OPUS4-56484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Herausforderungen in der additiven Fertigung sicherheitsrelevanter Komponenten N2 - Der Vortrag stellt nach einer kurzen allgemeinen Einleitung zur additiven Fertigung und des Laser Powder Bed Fusion Verfahrens einige Herausforderungen vor, die derzeitig den Einsatz von AM-Komponenten in sicherheitsrelevanten Anwendungen erschweren. Abschließend werden zwei Beispiele von Arbeiten der BAM gezeigt, die zur Überwindung dieser Herausforderungen beitragen können. T2 - Anwendertreffen des Laserverbundes Berlin-Brandenburg CY - Berlin, Germany DA - 25.11.2022 KW - Additive Fertigung KW - Laser Powder Bed Fusion PY - 2022 AN - OPUS4-56435 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, M. A1 - Bettge, Dirk A1 - Hilgenberg, Kai A1 - Binder, M. A1 - Dollmeier, K. A1 - Dreyer, M. A1 - Klöden, B. A1 - Schlingmann, T. A1 - Schmidt, J. T1 - Reproducibility and Scattering in Additive Manufacturing: Results from a Round Robin on PBF-LB/M AlSi10Mg Alloy T1 - Reproduzierbarkeit und Streuung bei der additiven Fertigung: Ergebnisse eines Ringversuchs mit einer PBF-LB/M AlSi10Mg-Legierung N2 - The round robin test investigated the reliability users can expect for AlSi10Mg additive manufactured specimens by laser powder bed fusion through examining powder quality, process parameter, microstructure defects, strength and fatigue. Besides for one outlier, expected static material properties could be found. Optical microstructure inspection was beneficial to determine true porosity and porosity types to explain the occurring scatter in properties. Fractographic analyses reveal that the fatigue crack propagation starts at the rough as-built surface for all specimens. Statistical analysis of the scatter in fatigue using statistical derived safety factors concludes that at a stress of 36.87 MPa the fatigue limit of 107 cycles could be reached for all specimen with a survival probability of 99.999 %. N2 - Im Rahmen eines Ringversuchs wurde durch die Untersuchung der Pulverqualität, der Prozessparameter, der Gefügefehler, der Festigkeit und der Ermüdung die Zuverlässigkeit bestimmt, die Nutzer von AlSi10Mg-Proben erwarten können, die mit pulverbettbasiertes Schmelzen mittels Laser (engl. Laser Powder Bed Fusion) gefertigt worden sind. Abgesehen von einem Ausreißer wurden die erwarteten statischen Materialeigenschaften erreicht. Eine optische Gefügeprüfung diente dazu, die tatsächliche Porosität und Arten von Porosität zu ermitteln, um die bei den Eigenschaften auftretende Streuung zu erklären. Fraktographische Unterschungen zeigen eine bei allen Proben von der rauen Oberfläche im As-built-Zustand ausgehende Ermüdungsrissausbreitung. Aus der statistischen Analyse der Streuung bezüglich der Ermüdung unter Anwendung von statistischen abgeleiteten Sicherheitsfaktoren geht hervor, dass alle Proben die Dauerfestigkeit von 107 Zyklen bei einer Spannung von 36,87 MPa mit einer Überlebenswahrscheinlichkeit von 99,999 % erreichten. KW - Additive manufacturing KW - Reproducibility KW - Reliability PY - 2022 DO - https://doi.org/10.1515/pm-2022-1018 SN - 2195-8599 VL - 59 IS - 10 SP - 580 EP - 614 PB - De Gruyter AN - OPUS4-55935 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Merz, Benjamin A1 - Nilsson, R. A1 - Garske, C. A1 - Hilgenberg, Kai T1 - Camera-based high precision position detection for hybrid additive manufacturing with laser powder bed fusion N2 - Additive manufacturing (AM) in general and laser powder bed fusion (PBF-LB/M) in particular are becoming increasingly important in the field of production technologies. Especially the high achievable accuracies and the great freedom in design make PBF-LB/M interesting for the manufacturing and repair of gas turbine blades. Part repair involves building AM-geometries onto an existing component. To minimise the offset between component and AM-geometry, a precise knowledge of the position of the component in the PBF-LB/M machine is mandatory. However, components cannot be inserted into the PBF-LB/M machine with repeatable accuracy, so the actual position will differ for each part. For an offset-free build-up, the actual position of the component in the PBF-LB/M machine has to be determined. In this paper, a camera-based position detection system is developed considering PBF-LB/M constraints and system requirements. This includes finding an optimal camera position considering the spatial limitations of the PBF-LB/M machine and analysing the resulting process coordinate systems. In addition, a workflow is developed to align different coordinate systems and simultaneously correct the perspective distortion in the acquired camera images. Thus, position characteristics can be determined from images by image moments. For this purpose, different image segmentation algorithms are compared. The precision of the system developed is evaluated in tests with 2D objects. A precision of up to 30μm in translational direction and an angular precision of 0.021∘ is achieved. Finally, a 3D demonstrator was built using this proposed hybrid strategy. The offset between base component and AM-geometry is determined by 3D scanning and is 69μm. KW - Laser powder bed fusion KW - Additive manufacturing KW - Hybrid repair KW - Machine vision KW - Image processing KW - Position detection PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568583 DO - https://doi.org/10.1007/s00170-022-10691-5 SP - 1 EP - 16 PB - Springer AN - OPUS4-56858 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Digitale Qualitätssicherung in der Additiven Fertigung N2 - Der Vortrag stellt das Pilotprojekt Additive Fertigung innerhalb von QI Digital vor und zeigt bisher Erreichtes. Dies umfasst eine digital durchgängige Baujobvorbereitung, automatisierte Datenerhebung und -registrierung sowie die Einbindung des Prozessmonitorings. Seitens der PTB wird ein digitaler Prüfbericht vorgestellt. T2 - QI Forum 2024 CY - Berlin, Germany DA - 09.10.2024 KW - Additive Fertigung KW - Digitale Qualitätssicherung KW - QI Digital PY - 2024 AN - OPUS4-61361 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poka, Konstantin A1 - Ali, Sozol A1 - Saeed, Waleed A1 - Merz, Benjamin A1 - Epperlein, Martin A1 - Hilgenberg, Kai T1 - Design and implementation of a machine log for PBF-LB/M on basis of IoT communication architectures and an ETL pipeline N2 - AbstractPowder Bed Fusion with Laser Beam of Metals (PBF-LB/M) has gained more industrial relevance and already demonstrated applications at a small series scale. However, its widespread adoption in various use cases faces challenges due to the absence of interfaces to established Manufacturing Execution Systems (MES) that support customers in the predominantly data-driven quality assurance. Current state-of-the-art PBF-LB/M machines utilize communication architectures, such as OPC Unified Architecture (OPC UA), Message Queuing Telemetry Transport (MQTT) and Representational State Transfer Application Programming Interface (REST API). In the context of the Reference Architecture Model Industry 4.0 (RAMI 4.0) and the Internet of Things (IoT), the assets, particularly the physical PBF-LB/M machines, already have an integration layer implemented to communicate data such as process states or sensor values. Missing is an MES component acting as a communication and information layer. To address this gap, the proposed Extract Transform Load (ETL) pipeline aims to extract relevant data from the fabrication of each build cycle down to the level of scan vectors and additionally to register process signals. The suggested data schema for archiving each build cycle adheres to all terms defined by ISO/TC 261—Additive Manufacturing (AM). In relation to the measurement frequency, all data are reorganized into entities, such as the AM machine, build cycle, part, layer, and scan vector. These scan vectors are stored in a runtime-independent format, including all metadata, to be valid and traceable. The resulting machine log represents a comprehensive documentation of each build cycle, enabling data-driven quality assurance at process level. KW - FAIR data KW - Data-driven quality assurance KW - Laser powder bed fusion PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601256 DO - https://doi.org/10.1007/s40964-024-00660-7 SN - 2363-9512 SP - 1 EP - 12 PB - Springer Science and Business Media LLC AN - OPUS4-60125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Hilgenberg, Kai T1 - Damage development and damage tolerance of structures manufactured by selective laser melting - a review N2 - The additive manufacturing technology of Selective Laser Melting (SLM) experiences a rapid development within an increasing marked of quite different application fields. The properties of SLM materials and structures are influenced by a number of tech-nological parameters such as the metal powder (particle size, homogeneity, cleanliness), the laser tool (power, beam diameter, pulse lengths), the scanning operation (speed, sequence and orientation of melting paths), parameters of the over-all equipment (design and preheating of the base plate, currents and turbulence in the protective gas atmosphere) and, last not least, the hatching strategy including the build-up direction of the structure with respect to the loading direction of the component. For the perspective use of SLM structures as load carrying, safety-relevant components the knowledge of their mechanical properties is necessary. It is essential to understand these in the context of the manufacturing-related features and at the back-ground of the basic characteristics of metallic materials: crystal lattice, microstructure and material defects. The paper provides an overview on factors which affect the mechanical parameters stiffness, strength, ductility, toughness, fatigue crack propagation and fatigue strength in the context of selective laser melting. T2 - FDMD 2017 CY - Lecco, Italy DA - 19.09.2017 KW - Fatigue strength KW - Fracture mechanics KW - Initial crack size KW - Short crack propagation KW - Multiple crack propagation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438511 DO - https://doi.org/10.1016/j.prostr.2017.11.071 SN - 2452-3216 VL - 7 SP - 141 EP - 148 PB - ScienceDirect CY - Lecco, Italy AN - OPUS4-43851 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fritzsche, André A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael A1 - Hilgenberg, Kai T1 - Einsatz einer elektromagnetischen Schmelzbadstütze beim Laserstrahl-(Hybrid)schweißen dickwandiger Stahlbauteile N2 - Die experimentellen Untersuchungen innerhalb dieses Berichtes zeigen die erfolgreiche Anwendung einer elektromagnetischen Schmelzbadstütze beim Laser-strahl(hybrid)schweißen von ferromagnetischen Stäh-len mit einer Werkstückdicke von bis zu 20 mm. Bis-lang wurde dieses System zur Kompensation des hydrostatischen Druckes von Aluminiumlegierungen und austenitischen Stählen eingesetzt. Zunächst wur-den die Versuche an Duplexstählen vorgenommen, die jeweils zur Hälfte aus Austenit und Ferrit bestehen. Im Anschluss daran wurden die Versuche auf bis zu 20 mm dicke Werkstücke aus Baustahl erweitert. In-nerhalb der Versuchsreihen wurden die AC-Leistung sowie die Oszillationsfrequenz variiert. Für Werk-stückdicken von 15 mm war eine AC-Leistung von ca. 1 kW notwendig, um die Wurzelüberhöhung in die Bewertungsgruppe B der für laserstrahlgeschweißten Stähle gültigen DIN EN ISO 13919-1:1996-09 einord-nen zu können. Mit zunehmender AC-Leistung wird die Wurzelüberhöhung sukzessive reduziert. Nach erfolg-reicher Erweiterung auf ferromagnetische Werkstoffe wurde die Anwendung der Technologie für das Laser-strahlhybridschweißen demonstriert, indem praxisrele-vante Y-Nähte an 20 mm dicken Baustählen ohne Wurzelüberhöhung einlagig in Wannenlage geschweißt wurden. Trotz der Beeinflussung des Lichtbogens durch das oszillierende Magnetfeld sowie des zusätz-lich zum hydrostatischen Druck zu berücksichtigenden Lichtbogendruckes wurde eine ideale Kompensation auf der Wurzelseite erzielt. Die Erweiterung des Anwendungsspektrums der elekt-romagnetischen Schmelzbadstütze auf ferromagneti-sche Werkstoffe sowie auf das Laserstrahlhybrid-schweißen eröffnet für zukünftige industrielle Anwen-dungen ein großes Potenzial. Das einlagige Schwei-ßen dickwandiger Bauteile mittels Hochleistungslasern wird in Kombination mit der elektromagnetischen Schmelzbadstütze attraktiver. In nachfolgenden Un-tersuchungen wird der Einsatz der elektromagneti-schen Schmelzbadstütze beim Laserstrahlhybrid-schweißen von Pipelinestählen angestrebt, v. a. im Hinblick auf die Spaltüberbrückbarkeit und der me-chanisch-technologischen Eigenschaften der Schweißverbindungen. Zudem ist beim Schweißen von Duplexstählen der Einsatz von Zusatzwerkstoffen zu berücksichtigen, um das Gleichgewicht zwischen austenitischer und ferritischer Phasen zu stabilisieren. T2 - DVS Congress 2017 CY - Düsseldorf, Germany DA - 26.09.2017 KW - Elektromagnetische Schmelzbadunterstützung KW - Ferromagnetischer Stahl KW - Laserstrahl-(Hybrid)schweißen PY - 2017 SN - 978-3-96144-008-5 VL - 337 SP - 331 EP - 336 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-42312 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Localized laser dispersing of titanium-di-boride with pulsed fiber laser N2 - In this paper, titanium-di-boride is dispersed on a cold-working tool steel by use of a pulsed fiber laser with high beam quality to produce separated and elevated surface features. The potential to adjust the geometry as well as the mechanical properties of the produced structures in dependence on the process parameters (pulse power, pulse duration) is described by means of metallographic and topographical investigations. It can be ascertained that very hard (hardness > 1000 HV1) surface features of different shape (spots and short lines) can be produced. They are characterized by a fine-grained microstructure resulting from a rapid solidification and finely dispersed TiB2 particles. Finally, the paper proposes different applications for this structuring technique. T2 - ICALEO 2017 - International congress on applications of lasers & electro-optics CY - Atlanta, GA, USA DA - 22.10.2017 KW - Laser dispersing KW - Titanium-di-boride KW - Surface structuring KW - Laser implantation PY - 2017 AN - OPUS4-42867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai A1 - Spranger, Felix A1 - Bachmann, Marcel T1 - Localized laser dispersing of titanium-di-boride with pulsed fiber laser N2 - In this paper, titanium-di-boride is dispersed on a cold-working tool steel by use of a pulsed fiber laser with high beam quality to produce separated and elevated surface features. The potential to adjust the geometry as well as the mechanical properties of the produced structures in dependence on the process parameters (pulse power, pulse duration) is described by means of metallographic and topographical investigations. It can be ascertained that very hard (hardness > 1000 HV1) surface features of different shape (spots and short lines) can be produced. They are characterized by a fine-grained microstructure resulting from a rapid solidification and finely dispersed TiB2 particles. Finally, the paper proposes different applications for this structuring technique. T2 - ICALEO 2017 - International congress on applications of lasers & electro-optics CY - Atlanta, GA, USA DA - 22.10.2017 KW - Laser dispersing KW - Titanium-di-boride KW - Surface structuring KW - Laser implantation PY - 2017 SN - 978-1-940168-1-42 SP - Paper 118, 1 EP - 9 AN - OPUS4-42868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Build-up strategies for additive manufacturing of three-dimensional Ti-6Al-4V-parts produced by Laser Metal Deposition N2 - Laser metal deposition (LMD) has been applied as coating technology for many years. Today, the technologies capacity to produce 3D depositions leads to a new field of application as additive manufacturing method. In this paper, 3D laser metal deposition of titanium alloy Ti-6Al-4V is studied with special regard to the demands of additive manufacturing. Therefore, only the powder nozzle is used to create the shielding gas atmosphere, which ensures high geometric flexibility. Furthermore, specimen with high aspect ratio and hundreds of layers are manufactured, which represent typical features in additive manufacturing. T2 - ICALEO CY - Atlanta, USA DA - 22.10.2017 KW - Additive manufacturing KW - Ti-6Al-4V KW - Laser Metal Deposition PY - 2017 AN - OPUS4-42865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - Anwendung der Laserimplantation zur Strukturierung verschleißgefährdeter Werkzeuge N2 - In einer Vielzahl technischer Anwendungen spielt die Aufrechterhaltung eines definierten Reibungs- und Verschleißverhaltens zwischen bewegten Oberflächen für die Sicherheit und Funktionalität eine entscheidende Rolle. Die Oberflächentechnik versucht durch geeignete Verfahren die Randschichten zu ertüchtigen, um Reibung und Verschleiß zu kontrollieren. Eine Verbesserung der Materialeigenschaften kann durch flächige Beschichtungen erreicht werden. Zusätzlich ermöglichen Oberflächenstrukturierungen breite Möglichkeiten zur Beeinflussung des Schmierungszustandes bzw. der Kontaktbedingungen. Neben Negativstrukturen bieten ebenfalls erhabene Mikrostrukturen großes Potenzial zur Beeinflussung des tribologischen Verhaltens. Ihr Einsatz ist aber aufgrund der besonderen Verschleißproblematik erhabener Strukturen momentan limitiert, so dass in der Regel zusätzliche verschleißreduzierende Beschichtungen notwendig werden. In diesem Beitrag wurde das Verfahren der Laserimplantation angewandt, mit dem erhabene und separierte Oberflächenstrukturen hoher Verschleißfestigkeit in einem Fertigungsschritt erzeugbar sind. Das Verfahren basiert auf einem lokalisierten Dispergieren von Hartstoffpartikeln. Hierfür wurde erstmalig ein gepulster Faserlaser mit hoher Strahlqualität zur Erzeugung punkt- und linienförmiger Mikrostrukturen angewandt. Versuche wurden auf dem Kaltarbeitsstahl X153CrMoV12 unter Anwendung von Titandiborid als Hartstoff durchgeführt. Anhand von Härtemessungen konnte gezeigt werden, dass sowohl punkt- als auch linienförmige Strukturen mit Härten über 1000 HV1 und einer feinkörnigen Mikrostruktur mit feinverteilten Hartstoffpartikeln herstellbar sind. Des Weiteren war es möglich, die Implantgeometrien, welche an Querschliffen und durch Weißlichtinterferometeraufnahmen erfasst wurden, durch die Pulsleistung und Pulsdauer zu steuern. T2 - 38. Assistentenseminar der WGF CY - Rabenau, Germany DA - 06.09.2017 KW - Laserimplantation PY - 2018 SN - 978-3-96144-028-3 VL - 342 SP - 24 EP - 33 CY - Düsseldorf AN - OPUS4-47295 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spranger, Felix A1 - Graf, B. A1 - Schuch, M. A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - Build-up strategies for additive manufacturing of three dimensional Ti-6Al-4V-parts produced by laser metal deposition N2 - Laser metal deposition (LMD) has been applied as a coating technology for many years. Today, the technologies capacity to produce 3D depositions leads to a new field of application as additive manufacturing method. In this paper, 3D laser metal deposition of titanium alloy Ti-6Al-4V is studied with special regard to the demands of additive manufacturing. Therefore, only the coaxial LMD powder nozzle is used to create the shielding gas atmosphere, which ensures high geometric flexibility. Furthermore, specimen with high aspect ratio and hundreds of layers are manufactured, which represent typical features in additive manufacturing. The presented study contains the following steps: First, cylindrical specimens are manufactured with a standard shell-core build-up strategy and mechanical properties as well as fracture mechanisms are determined. Based on the results, experiments are conducted to improve the build-up strategy and new tensile test specimens are built with the improved strategy. The improved strategy incorporates variable track overlap ratios to achieve a constant growth in the shell and core area. As blanks, lean cylinders comprising more than 240 layers and a height of more than 120mm are manufactured. The specimens are analyzed by X-ray inspection for material defects. Fractured surfaces are observed via scanning electron microscopy and the composition of the surfaces is determined using energy dispersive X-ray spectroscopy. The tensile test results prove mechanical properties close to ASTM F1108 specification for wrought material. KW - Laser metal deposition KW - Ti-6Al-4V KW - Additive manufacturing KW - Titanium alloy KW - Turbine components PY - 2018 DO - https://doi.org/10.2351/1.4997852 SN - 1938-1387 SN - 1042-346X VL - 30 IS - 2 SP - UNSP 022001, 1 EP - 13 PB - Laser Institute of America AN - OPUS4-44655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - Anlagen zur Additiven Fertigung und Einfluss auf die Bauteilqualität N2 - Kurzüberblick zur AM-Anlagentechnik bei metallischen Werkstoffen und Betriebseinflüssen auf die Bauteilqualität am Beispiel Selective-Laser-Melting T2 - Round-Table Zertifizierung additiv gefertigter Druckgeräte CY - Berlin, Germany DA - 04.07.2018 KW - Additive Fertigung KW - Anlagen PY - 2018 AN - OPUS4-45437 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai T1 - EOS M300 as the heart of the QI living lab: Advancing with digital process chains N2 - This presentation shows how the connectivity of the EOS-M300/4 laser powder bed system is used to capture machine and process data as part of the living lab in QI Digital and how this can enable future digital quality assurance in additive manufacturing. T2 - AM Forum 2025 CY - Berlin, Germany DA - 17.03.2025 KW - Additive manufacturing KW - Quality assurance KW - QI Digital KW - Living lab PY - 2025 AN - OPUS4-62740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai A1 - Madia, Mauro T1 - Additive Fertigung von Bauteilen und Strukturen – Grenzen, Risiken, Chancen N2 - Dieser Eröffnungsvortrag des DVM-Tages beleuchtet Herausforderungen in der additiven Fertigung und plädiert für eine enge Zusammenarbeit von Fertigungstechnik und Bruchmechanik für die Vorhersage der Lebensdauer AM-gefertigter Komponenten. T2 - DVM-Tag CY - Berlin, Germany DA - 08.04.2025 KW - Additive Fertigung KW - Digitale Qualitätssicherung KW - Ermüdungsfestigkeit PY - 2025 AN - OPUS4-62971 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poka, Konstantin A1 - Ali, Sozol A1 - Saeed, Waleed A1 - Merz, Benjamin A1 - Epperlein, Martin A1 - Hilgenberg, Kai T1 - Quality assurance via a cyber physical system of a PBF-LB/M machine N2 - Powder Bed Fusion with Laser Beam of Metals (PBF-LB/M) faces challenges in reproducibility and quality assurance, even for widely applied alloys like AlSi10Mg. This work introduces a digital provenance framework for PBF-LB/M, showcased through the EOS M 300–4 multi-laser machine. An Extract, Transform, Load (ETL) pipeline autonomously captures machine data, including scan vectors as well as process signals, and organizes them into a Digital Shadow (DS). The DS is further extended by external data sources, such as Melt Pool Monitoring (MPM), to enable comprehensive analysis and root cause identification. This approach ensures continuous data representation and facilitates the development of new quality metrics. Moreover, the framework enhances quality assurance and traceability, supports compliance with industry standards, and improves productivity. It also enables more precise cost calculations and predictive maintenance. By addressing these challenges, the framework is essential for advancing PBF-LB/M in industrial applications, achieving greater consistency and scalability in production. KW - PBF-LB/M KW - Data driven quality assurance KW - Data engineering KW - Digital shadow PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625187 DO - https://doi.org/10.1007/s40964-025-00978-w SN - 2363-9520 VL - 10 IS - 3 SP - 1771 EP - 1783 PB - Springer Science and Business Media LLC AN - OPUS4-62518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kempf, A. A1 - Hilgenberg, Kai T1 - Einfluss der Porosität auf die Duktilitätseigenschaften von additiv gefertigtem AlSi10Mg N2 - Die Werkstoffeigenschaften im selektiven Laserstrahlschmelz-Verfahren hergestellter Bauteile werden von einer Vielzahl technologischer Parameter beeinflusst, sodass sich die Fertigungsgüte verschiedener Anlagen voneinander unterscheiden kann. Vor diesem Hintergrund wurde in der vorliegenden Arbeit untersucht, inwiefern sich durch verschiedene nachgelagerte Wärmebehandlungen die Mikrostruktur und die quasistatischen Festigkeitseigenschaften von Proben aus der Aluminiumlegierung AlSi10Mg, die mit verschiedenen Anlagen, Pulvern, Belichtungsstrategien und Prozessparametern gefertigt wurden, harmonisieren lassen. Die Versuche zeigten u.a., dass die erheblichen Festigkeitsunterschiede im Ausgangszustand unabhängig von der angewendeten Wärmebehandlungsroute aufgehoben wurden. Dennoch wurden signifikante Unterschiede in der Duktilität ermittelt. Anhand umfangreicher Bruchflächenanalysen konnte nachgewiesen werden, dass die in der Bruchfläche ermittelte Porosität eine lineare Korrelation zu der Bruchdehnung aufwies. T2 - 5. Tagung des Arbeitskreises Additiv gefertigte Bauteile und Strukturen CY - Online Meeting DA - 04.11.2020 KW - Wärmebehandlung KW - Additive Fertigung KW - Laser powder bed fusion KW - AlSi10Mg KW - Ringversuch PY - 2020 SN - 2509-8772 VL - 405 SP - 93 EP - 104 AN - OPUS4-51657 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werner, Tiago A1 - Teske, Tanita A1 - Hilgenberg, Kai A1 - Mauro, Madia A1 - Nielsen, S. A1 - Gärtner, F. A1 - Klassen, T. T1 - Untersuchung des Potenzials von Kaltgasspritzen für die Reparatur zyklisch belasteter Bauteile T1 - Investigation on the capability of cold-spray for repair of cyclically loaded components N2 - Die Reparatur mittels Kaltgasspritzen ist eine vielversprechende Alternative zum teuren Austausch fehlerbehafteter Bauteile in der Luft- und Raumfahrt. Im Rahmen dieser Arbeit wurde das Potential des Verfahrens an der hochfesten Aluminiumlegierungen Al6061-T6 unter Anwendung von Stickstoff als kostengünstiges Prozessgas untersucht. Es wurden quasi-statische Zugversuche und einachsige Zeitfestigkeitsversuche mit besonderem Fokus auf das in-situ Kugelstrahlen zur Verbesserung der mechanischen Eigenschaften durchgeführt. Im Ergebnis wurde die Verbesserung der Adhäsion zwischen Substrat und aufgebautem Werkstoff als entscheidendes Kriterium für eine Anwendbarkeit ermittelt. Die Laserstrukturierung von Substratoberflächen ist hierfür vielversprechend und wurde im Rahmen der Arbeit mittels Adhäsionsversuchen untersucht. N2 - Repair by cold-spray is a promising alternative to the costly replacement of flawed components in aerospace applications. In the present work this process was investigated on the high-strength aluminum alloy Al6061-T6. For the cold-spray process, inexpensive Nitrogen was used as process-gas. Quasi-static tensile and highcycle- fatigue tests (HCF) were performed, focusing on in-situ shot peening to improve the mechanical properties of the repaired part. An improved adhesion between substrate and built-up material was identified as a key-factor for the applicability of the process. Under this respect laser-structuring of the substrate surface was applied and its effect on the mechanical performance of the restored samples were examined by adhesion tests. T2 - 9. Tagung des DVM-Arbeitskreises Additiv gefertigte Bauteile und Strukturen CY - Stuttgart, Germany DA - 06.11.2024 KW - Kaltgasspritzen KW - cold-spray KW - Reparatur KW - Repair KW - Ermüdungsfestigkeit KW - Fatigue KW - Luft- und Raumfahrt KW - Aerospace KW - Substratvorbehandlung KW - Substrate pre-treatment PY - 2024 DO - https://doi.org/10.48447/ADD-2024-BB VL - 409 SP - 67 EP - 79 AN - OPUS4-63182 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai A1 - Rethmeier, Michael A1 - Steinhoff, K. T1 - Surface structuring by pulsed laser implantation N2 - Micrometric surface topologies are required for a wide range of technical applications. While lowered surface features have been used for many years to improve the tribological behavior of contacting surfaces, there are also other fields of application, where the potential of elevated surface features is known, e. g. for metal forming tools. However, the demand for a high wear resistance of these structures often inhibits an industrial application. A solution is offered by structuring techniques that use additional material. A promising approach is the localized dispersing of hard ceramic particles by pulsed laser radiation, the so-called laser implantation. This paper describes the potential to adjust the geometry as well as the mechanical properties of laser implanted surfaces by means of microstructural and topological investigations. Afterwards, results of a wear test are given and different applications for this structuring technique are discussed. It can be shown that dome-shaped or ring-shaped structures on a micrometric scale can be produced with high hardness and wear resistance. T2 - THERMEC 2016: 9th International Conference on Processing & Manufacturing of Advanced Materials CY - Graz, Austria DA - 29.05.2016 KW - Surface structuring KW - Metal forming tools KW - Laser implantation KW - Laser dispersing PY - 2017 DO - https://doi.org/10.4028/www.scientific.net/MSF.879.750 SN - 1662-9752 VL - 879 SP - 750 EP - 755 PB - Trans Tech Publications CY - Schweiz AN - OPUS4-38927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Zerbst, Uwe A1 - Hilgenberg, Kai ED - Richard, H. A. ED - Zipsner, T. ED - Schramm, B. T1 - Schadensentwicklung und Schadenstoleranz von SLM-gefertigten Strukturen N2 - Unterschiedliche Werkstoffeigenschaften reagieren auf jeweils spezifische Weise auf Gittertyp, Gefüge und Defekte. Für die schadenstolerante Betrachtung von Werkstoff und Bauteil ist das Verständnis dieser Zusammenhänge essentiell. Der Beitrag gibt mit Hinblick auf additiv gefertigte metallische Bauteile mittels Selective Laser Melting einen kurzen, keineswegs vollständigen Überblick über Faktoren, die die Steifigkeit, Festigkeit, Duktilität, Zähigkeit, Ermüdungsrissausbreitung und Schwingfestigkeit beeinflussen. Es wird aufgezeigt, wie die bruchmechanische Betrachtung zur Quantifizierung der Zusammenhänge beitragen kann. KW - Additive Fertigung KW - Selective Laser Melting (SLM) KW - Werkstoffeigenschaften KW - Schadenstoleranz KW - Bruchmechanik PY - 2017 SN - 978-3-658-17779-9 DO - https://doi.org/10.1007/978-3-658-17780-5 SP - 241 EP - 270 PB - Springer Vieweg CY - Wiesbaden AN - OPUS4-40162 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hilgenberg, Kai A1 - Steinhoff, K. T1 - Texturing of skin-pass rolls by pulsed laser dispersing N2 - Skin-pass rolling is a substantial process step in the production line of sheet material for automotive applications. Textured rolls are used to emboss an immaterial surface structure on sheets for improving their formability in subsequent deep drawing operations. In this paper, state of the art techniques for texturing skin-pass rolls are discussed in order to assess their ability to meet optimal tribological parameters. Two main problems are identified: firstly, structured rolls are affected by ongoing wear limiting the operating time and necessitates perpetual maintenance. Secondly, state of the art techniques are not able to exploit the theoretically known potential of immaterial surface structures for enabling micro-lubrication mechanisms due to geometrical inadequacies. Based on these findings, a new approach for texturing of skin-pass rolls is introduced. The technique uses a localised dispersing of hard ceramic particles by use of pulsed laser radiation. It is shown in this paper that this technique allows the creation of elevated structures with high hardness on the surface of 1.2379 cold-working steel. The wear behaviour of such textured rolls was investigated in a lubricated twin-disc-test. The experiments show that no significant wear of the laser produced structures occur during the test duration. The observed results lead to the assumption that the proposed technique allows the creation of skin-pass roll structures with significantly higher durability. KW - Skin-pass rolling KW - Roll texturing KW - Pulsed laser dispersing KW - Laser implantation KW - Oberflächenstrukturierung KW - Dressierwalzen KW - Laserimplantation PY - 2015 DO - https://doi.org/10.1016/j.jmatprotec.2015.05.027 SN - 0924-0136 SN - 1873-4774 VL - 225 SP - 84 EP - 92 PB - Elsevier CY - Amsterdam AN - OPUS4-33729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kempf, A. A1 - Hilgenberg, Kai T1 - Influence of sub-cell structure on the mechanical properties of AlSi10Mg manufactured by laser powder bed fusion N2 - AlSi10Mg is one of the most applied alloys for laser powder bed fusion (LPBF) technology, due to its great possibilities for implementing new lightweight concepts such as in automotive industries. For the component design it is necessary to know about the mechanical properties and the mechanical behaviour. The many published strength properties of LPBF processed AlSi10Mg show significant differences up to approximately 225 MPa in ultimate tensile strength (UTS) and 195 MPa in yield strength (YS). To understand these varying properties, a ring trial was carried out manufacturing specimens on 6 LPBF machines with different parameters and build-up strategies. They were studied in the as-built (AB) condition and after heat treatment at 300 °C for 30 min, respectively. For examining the mechanical properties, tensile tests and hardness measurements were carried out. The microstructure was characterized by optical light microscopy (OM), field emission scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). The identified differences in strength properties were discussed based on the 4 strengthening mechanism known for metallic materials and at the background of material defects. It was found that the size of the typical sub-cell structure of LPBF AlSi10Mg affected substantially the mechanical properties in the AB condition, in which with decreasing sub-cell size strength increased. If heat treatment was applied, the strength properties decreased and did not differ anymore. Since annealing led to coarsened sub-cells, whereas the grains itself did not change in size, the influence of sub-cell structure on strength was further confirmed. In addition, acicular precipitates in the AB condition were observed at specimens from one LPBF machine showing the lowest tensile elongation. KW - Laser powder bed fusion KW - AlSi10Mg KW - Mechanical properties KW - Microstructure PY - 2020 DO - https://doi.org/10.1016/j.msea.2020.138976 VL - 776 SP - Paper 138976, 12 PB - Elsevier B.V. AN - OPUS4-50316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dávila, Josué A1 - Mohr, Gunther A1 - Hilgenberg, Kai T1 - Parameter development for Laser Powder Bed Fusion of nickel-based Haynes 282 using diverse density determination methods N2 - To manufacture functional components using laser powder bed fusion (PBF-LB/M), the execution of a parameter development with the specific material and machine is an indispensable step. Typically, in the search for the optimal parameter set, the volumetric energy density (VED) used to melt the material serves as an adjustment variable, while the resulting part density as the target parameter. Although this approach effectively reduces the process parameters search-space, additional criteria concerning part quality should be considered in the development. This paper introduces a systematic parameter selection approach, refining the characterization process for processing the nickel-based superalloy Haynes® 282®. The presented strategy not only incorporates the density as target condition but also considers the surface quality and dimensional accuracy of the manufactured samples, crucial for near-net-shape manufacturing. Additionally, three porosity measurement methods (Archimedes method, microscopy, gaspycnometry) for AM metal parts are compared, and their validity for this purpose is discussed. T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024] CY - Fürth, Germany DA - 15.09.2024 KW - Additive Manufacturing KW - Laser powder bed fusion (PBF-LB/M) KW - Archimedes principle KW - Parameter development KW - Gaspycnometry KW - Density determination method KW - Density optimization PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624417 VL - 124 SP - 93 EP - 97 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-62441 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, André A1 - Hilgenberg, Kai A1 - Teichmann, F. A1 - Pries, H. A1 - Dilger, K. A1 - Rethmeier, Michael T1 - Improved degassing in laser beam welding of aluminum die casting by an electromagnetic field N2 - The paper describes an experimental investigation of the electromagnetic porosity reduction in partial penetration laser beam welding of 6 mm thick aluminum die casting AlSi9MnMg. The Investigation reveals that the usage of an electromagnetic field leads to a significant reduction of the porosity as well as to a surface smoothing of aluminum die casting. Based on the reference case without an electromagnetic influence, the porosity area was reduced gradually up to 76%. Metallurgical pores as well as process pores were removed from the weld pool. Also the weld reinforcement was improved up to 78%. Best results were reached with a frequency of 4325 Hz and a magnetic flux density of 348 mT. Although a complete prevention of porosity was not achieved, the best weld seam reached a high quality and can be ranked in valuation group B of DIN EN ISO 13919-2:2001–12. KW - Laser beam welding KW - Die-cast aluminum KW - Porosity reduction KW - Electromagnetic influence PY - 2018 DO - https://doi.org/10.1016/j.jmatprotec.2017.10.021 SN - 0924-0136 VL - 253 SP - 51 EP - 56 PB - Elsevier CY - Amsterdam AN - OPUS4-42767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fritzsche, André A1 - Hilgenberg, Kai A1 - Teichmann, F. A1 - Pries, H. A1 - Rethmeier, Michael T1 - Electromagnetic porosity Reduction in Laser Beam Welding of Die-Cast Aluminum Alloy N2 - The present paper investigates the electromagnetic porosity reduction in partial penetration laser beam welding of 6 mm aluminum die casting AlSi9MnMg. Applying an electromagnetic field, a significant reduction of the porosity as well as smoothing of the surface of aluminum die casting can be observed. Starting from the reference case without an electromagnetic support, the porosity was reduced by 76 %. Especially big pores can be removed from the weld pool effectively due to their beneficial volume-to-area ratio whereas very small metallurgical pores tend to remain within the weld pool even when higher magnetic flux densities are applied. T2 - Lasers in Manufacturing Conference 2017 CY - Munich, Germany DA - 26.06.2017 KW - Laser beam welding KW - Die-cast aluminum KW - Porosity reduction KW - Electromagnetic influence PY - 2017 SP - 1 EP - 10 AN - OPUS4-41244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brunner-Schwer, C. A1 - Simón Muzás, Juan A1 - Biegler, M. A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - Laser Welding of L-PBF AM components out of Inconel 718 N2 - With regard to efficient production, it is desirable to combine the respective advantages of additively and conventionally manufactured components. Particularly in the case of large-volume components that also include filigree or complex structures, it makes sense to divide the overall part into individual elements, which afterwards have to be joined by welding. The following research represents a first step in fundamentally investigating and characterizing the joint welding of Laser Powder Bed Fusion (L-PBF) components made of Inconel 718. For this purpose, bead-on-plate welds were performed on plates manufactured using the L-PBF process and compared with the conventionally manufactured material. Conventional laser beam welding was used as welding process. The weld geometry was investigated as a function of the L-PBF build-up orientation. It was found that the welding depth and weld geometry differ depending on this orientation and in comparison to the conventional material. T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022] CY - Fürth, Germany DA - 04.09.2022 KW - Laser Welding KW - L-PBF KW - PBF-LB/M KW - Seam geometry KW - Bead-on-plate welds PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560012 DO - https://doi.org/10.1016/j.procir.2022.08.072 SN - 2212-8271 VL - 111 SP - 92 EP - 96 PB - Elsevier B.V. AN - OPUS4-56001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -