TY - CONF A1 - Schirdewahn, S. A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Merklein, M. ED - Merklein, M. T1 - Untersuchung des tribologischen Einsatzverhaltens von lokal dispergierten Presshärtewerkzeugoberflächen N2 - Das Presshärteverfahren hat sich zur ressourceneffizienten Verarbeitung von höchstfesten Stahlwerkstoffen im Karosserieleichtbau weltweit etabliert. Die fehlerfreie Bauteilproduktion wird jedoch durch Reibungs- und Verschleißerscheinungen aufgrund hoher thermo-mechanischer Werkzeugbelastungen und fehlender Schmierstoffsysteme limitiert. Als Lösungsansatz wird eine Modifikation der Werkzeugoberfläche mittels Laserimplantation angestrebt, um folglich deren Verschleißbeständigkeit nachhaltig zu erhöhen. Das Verfahren basiert auf einem lokalen Dispergieren keramischer Hartstoffpartikel in die Werkzeugoberfläche, infolgedessen hochfeste und erhabene Strukturen im Mikrometerbereich entstehen. Aufgrund der signifikanten Reduzierung der Kontaktfläche sowie der hohen Verschleißbeständigkeit der eingesetzten TiB2-Hartstoffe wird ein verbessertes tribologisches Einsatzverhalten unter presshärtetypischen Prozessbedingungen erwartet. Zur Verifizierung dieser Annahmen wurden im Rahmen dieser Arbeit modifizierte Pin-on-Disk Tests durchgeführt, um das Reib- und Verschleißverhalten der laserimplantierten Werkzeugoberflächen unter Presshärtebedingungen zu untersuchen. Zur weiteren Vertiefung des Prozess-verständnisses wurden die verschlissenen Platinen via Tastschnittmessungen und Querschliffaufnahmen analysiert. Durch den Ergebnisvergleich mit konventionellen Werkzeugoberflächen erfolgte eine abschließende Bewertung des tribologischen Einsatzverhaltens der laserimplantierten Strukturen. T2 - 14. Erlanger Workshop Warmblechumformung 2019 CY - Fürth, Germany DA - 19.11.2019 KW - Laserimplantation KW - TiB2 KW - X38CrMoV5-3 KW - Presshärten KW - Tribologie PY - 2019 SP - 169 EP - 178 PB - Meisenbach Verlag Bamberg CY - Bamberg AN - OPUS4-49703 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schirdewahn, S. A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Merklein, M. ED - M., Oldenburg ED - J., Hardell ED - D., Caellas T1 - Tribological performance of localized dispersed X38CrMoV5-3 surfaces for hot stamping of Al-Si coated 22MnB5 sheets N2 - Over the last years, the weight of modern car bodies has risen significantly due to the increasing customers’ demand for comfort and safety equipment. However, this ongoing trend leads to an increasing fuel consumption and thus to higher carbon dioxide emissions. In order to counteract these problems, hot stamping has been established in the automotive industry as a key technolo-gy for lightweight construction, regarding the manufacturing of safety-relevant car body compo-nents. Hot stamped parts are commonly made out of boron-manganese steel 22MnB5, which is initially austenized and subsequently formed and quenched in one process step. As a result, geo-metrical complex structures with an ultimate tensile strength of 1500 MPa are generated. The surfaces of the workpieces are coated with an Al-Si layer to avoid oxide scale formation and to ensure corrosion protection. However, the coating system leads to an increased adhesive wear on the tool surface due to the high thermo-mechanical tool stresses. Therefore, a time and cost con-suming rework of the hot stamping tools is required. The aim of this study is to increase the tribological performance of hot stamping tools by using a laser implantation process. This tech-nique allows the ma-nufacturing of separated, elevated and dome-shaped microstructures on the tool surface in consequence of a localized dispersing of hard ceramic particles by pulsed laser radiation. The generated surface features offer great potential for reducing the tribological load, due to their high hardness and wear resistance. For this purpose, the friction coefficient of un-modified and laser implanted tool surfaces were examined and compared by using a modified pin-on-disk test. In addition, the surfaces were analyzed by optical measurements in order to quantify the amount of wear. T2 - 7th International Conference on Hot Sheet Metal Forming of High-Performance Steel CHS2-2019 CY - Lulea, Sweden DA - 02.06.2019 KW - Laser implantation KW - Surface texturing KW - X38CrMoV5-3 KW - TiB2 KW - Hot-Stamping PY - 2019 VL - 2019 SP - 357 EP - 364 AN - OPUS4-48285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai A1 - Mohr, Gunther A1 - Altenburg, Simon A1 - Ulbricht, Alexander A1 - Seeger, Stefan T1 - Prozessmonitoring für die additive Fertigung: Entwicklungen an der BAM N2 - Das Prozessmonitoring stellt einen wichtigen Baustein für eine Qualitätssicherung additiv gefertigter Bauteile dar, insbesondere bei kleinen Losgrößen. Der Vortrag zeigt einen Überblick aktueller Entwicklungen der BAM im Bereich des Prozessmonitorings für das Laserstrahlschmelzen (laser powder bed fusion) metallischer Werkstoffe. Durch Vergleich mit der Referenzmethode Computertomografie wird am Beispiel der thermografischen Verfahren gezeigt, wie relevante Defekte in Bauteilen detektiert werden können und Einsatzpotenziale sowie Limitierungen aufgezeigt. T2 - Forum Additive Fertigung Rheinland-Pfalz CY - Ludwigshafen, Germany DA - 07.11.2019 KW - Optische Tomografie KW - Additive Fertigung KW - Prozessmonitoring KW - Thermografie PY - 2019 AN - OPUS4-49958 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF 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 a 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 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 a 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 the pulse power and pulse duration, their dispersing behavior and influence on the material properties of AISI D2 tool steel was 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 pre-placed 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 HV1 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 - 38th International Congress on Applications of Lasers & Electro-Optics CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser implantation KW - Surface texturing KW - AISI D2 KW - TiB2 PY - 2019 SN - 978-1-940168-1-42 SP - 1 EP - 10 AN - OPUS4-49317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spranger, Felix A1 - Oliveira Lopes, M. A1 - Schirdewahn, S. A1 - Merklein, M. A1 - Hilgenberg, Kai T1 - Microstructural evolution and geometrical properties of TiB2 metal matrix composite protrusions on hot work tool steel surfaces manufactured by laser implantation N2 - The laser implantation–named technique aims to address the tribological problems frequently seen on tool surfaces during hot stamping. It is based on the creation of elevated dome- or ring-shaped hard structures on the surface of tool steels by a localized dispersing of hard particles. Therefore, a combination of the two distinct approaches that are normally used in surface Technology for optimizing friction and wear, i.e., surface texturing and surface material optimization, are realized in one processing step. In experimental studies, a localized dispersing of TiB2 particles in the surface layer of the hot work tool steel X38CrMoV5-3 was considered and compared with punctual laser–remelted textures. The structures (micro-) hardness was measured at top- and cross-sections. With the aid of a scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction the interaction between the hard particles and the substrate material were studied. From the results, an optimal parameter range was identified for laser implantation. To the investigation’s end, the implant geometry was measured by optical microscopy and White light microscopy. Furthermore, a mathematic model was introduced, which allows a prediction of the implant geometry as a response to the laser parameters. It was shown that the implantation of TiB2 particles leads to a significant hardness increase up to 1600 HV1 due to the dispersion of initial particles and an in situ precipitation of new titanium-rich phases. It was possible to create defect-free dome- and ring-shaped microstructures on the surfaces. It was also shown that the implants geometry highly depends on the applied laser parameters. The applied central composite design shows a good agreement with the experimental results. KW - Laser implantation KW - Surface texturing KW - X38CrMoV5-3 KW - TiB2 KW - Hot-Stamping PY - 2019 U6 - https://doi.org/10.1007/s00170-019-04630-0 SN - 0268-3768 VL - 2019 SP - 1 EP - 23 PB - Springer-Verlag London Ltd. CY - London AN - OPUS4-49827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mohr, Gunther A1 - Seeger, Stefan A1 - Hilgenberg, Kai T1 - Measurement of particle emissions in Laser Powder Bed Fusion (L-PBF) processes and its potential for in-situ process monitoring N2 - Laser Powder Bed Fusion (L-PBF) is a promising additive manufacturing (AM) technology for metal part production especially for complex and lightweight structures or functional designs. In L PBF processes several by-products including welding plume and its condensates, spatter and ejected powder are generated during laser exposure. Investigations of micro- and nano-sized by-products have received little attention in literature. This study focuses on the analysis of particle emissions in L PBF of 316L stainless steel using a scattered light aerosol spectrometer and a fast mobility particle sizer spectrometer during the process which allows for in-situ analysis of particle sizes in the range of 6 nm to 100 µm. A distinct correlation of emission signals to part position can be revealed. In addition, a significant influence of laser scanning vector directions on emission signals is presented. Furthermore, differing powder layer thicknesses can be recognised by deviations in emission signals. T2 - Euro PM 2019 CY - Maastricht, The Netherlands DA - 13.10.2019 KW - Plume KW - Laser Powder Bed Fusion (L-PBF) KW - Additive Manufacturing (AM) KW - Spatter KW - Fume KW - Particle gas emission KW - Aerosol measurements PY - 2019 SP - 1 EP - 7 AN - OPUS4-49388 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hilgenberg, Kai A1 - Spranger, Felix T1 - Localized laser surface treatments of metals: State of the art and new developments N2 - Localized laser surface treatments are able to produce tailor-made surface properties to fulfill requirements of a variety of technical applications. Especially micrometric surface topologies can be beneficial for optimizing tribological contact situations. Structures with lowered surface features are already utilized for bearings or cylinders of combustion engines. There are also other fields of application, where the potential of protruding surface features is known, e. g. for metal forming tools. A promising approach for a tailored surface treatment working in the microsecond range is the localized dispersing of hard ceramic particles by pulsed laser radiation, the so-called laser implantation. This technique is able to produce micrometric surface structures and to improve simultaneously the wear resistance by creating metal matrix composites. In this talk, the laser implantation technique is described and compared to the state of the art. The potential to adjust the geometry as well as the mechanical properties of laser implanted surfaces is demonstrated by means of microstructural and topographical investigations of different ceramic materials and steel substrates. Finally, results of research projects are presented aiming on the application of such structured surfaces. Their capability to change and optimize friction and wear are demonstrated for fully lubricated contacts, tools for hot sheet metal forming and tools for cold rolling of sheets for automotive applications. T2 - 10th International Conference on Laser Applications (ICLA 10) CY - Cairo, Egypt DA - 23.11.2019 KW - Tool steel KW - Laser implantation KW - Laser surface texturing KW - Laser dispersing PY - 2019 AN - OPUS4-49959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spranger, Felix A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - Laserimplantation von TiB2-Partikeln in X153CrMoV12 Kaltarbeitsstahl und Ihr Einfluss auf die Materialeigenschaften N2 - Die Laserimplantation erlaubt die Herstellung verschleißbeständiger, erhabener Mikrostrukturen (Implants) auf Stahloberflächen durch ein diskontinuierliches Dispergieren von keramischen Partikeln mittels gepulster Laserstrahlung. Durch die flexible Anordnung separierter Implants zu komplexen Mustern erlaubt das Verfahren eine gezielte Oberflächenstrukturierung zur Beeinflussung des Reibungs- und Verschleißverhaltens. Insbesondere erwies sich Titandiborid (TiB2) als Implantationsmaterial für geeig-net, da eine Manipulation der Implantgeometrie in einem breiten Bereich vorgenommen werden konnte, ohne dass Materialdefekte wie Risse oder Poren auftraten. Ziel der Untersuchungen war es, den Einfluss implantierter TiB2-Partikel auf die Materialeigenschaften von X153CrMoV12 zu ermitteln. Hierfür wurden im Rahmen der Arbeit die Laserparameter (Pulsleistung und -dauer) in einem breiten Parameterfeld variiert und vergleichende Untersuchungen an TiB2 implan-tierten Zonen sowie an punktuell umschmelzstrukturierten Zonen durchgeführt. Die Ergebnisse zeigen, dass eine reine Umschmelzstrukturierung zu einer deutlichen Reduktion der Oberflächenhärte aufgrund erhöhter Restaustenitgehalte (γR) führt. Im Gegensatz dazu führt das Laserimplantieren von TiB2-Partikeln zu einer deutlichen Härtesteigerung in den kuppel- oder ringförmigen Implants. Härtewerte von bis zu 1800 HV1 resultieren aus dispergierten TiB2-Primärpartikeln sowie in-situ ausgeschiedenen Se-kundärphasen, durch die der Restaustenitanteil zudem deutlich reduziert wird. T2 - 39. Assistentenseminar Füge- und Schweißtechnik CY - Eupen, Belgium DA - 12.09.2018 KW - Laserimplantation KW - TiB2 KW - AISI D2 KW - Laserdispergieren PY - 2019 SN - 978-3-96144-070-2 VL - Band 356 SP - 51 EP - 59 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-48751 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spranger, Felix A1 - Hilgenberg, Kai T1 - Laser implantation: An innovative technique for surface texturing N2 - The laser implantation technique bases on a localized dispersing of ceramic particles in metallic surface layers for changing their micro geometry as well as their material properties. Using TiB2 and NbC hard particles, tailored microtextures consisting of elevated dome-, ring-, or line-shaped Features can be manufactured. Especially TiB2 implants feature high hardness values up to 1800 HV1 and ceramic particle contents up to 55 %, indicating superior wear resistant properties. KW - Laser implantation KW - Surface texturing KW - AISI D2 KW - TiB2 KW - NbC PY - 2019 UR - https://onlinelibrary.wiley.com/doi/epdf/10.1002/phvs.201900002 U6 - https://doi.org/10.1002/phvs.201900002 SN - 2626-1294 VL - 16 IS - 1 SP - 38 EP - 41 PB - WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim CY - Weinheim AN - OPUS4-47290 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spranger, Felix A1 - Oliveira Lopes, M. A1 - Schirdewahn, S. A1 - Merklein, M. A1 - Hilgenberg, Kai T1 - Investigations on TaC Localized Dispersed X38CrMoV5-3 Surfaces With Regard to the Manufacturing of Wear Resistant Protruded Surface Textures N2 - The potential of lowered surface features as well as the application of wear resistant coatings have been known for many years to improve the tribological behavior of forming tools. More recent studies also discuss the capability of protruded microfeatures for adjusting the tribological behavior between contacting surfaces. The demand for a high wear resistance of such structures as well as their economical and reliable production, however, often limits the industrial application. The laser implantation process can overcome these limitations. In contrast to conventional cw-laser dispersing processes, where the formation of uniform metal matrix composite layers is intended, this surface engineering technique aims to improve the tribological behavior of contacting surfaces by a localized dispersing of pre-placed hard ceramic particles. This enables the formation of deterministic textures composed of separated wear resistant dome- or ring-shaped microstructures (implants). Since TaC shows very promising material properties for improving the wear resistance of tools exposed to severe operating conditions, this paper analyzes its suitability for pulsed laser implantation on X38CrMoV5-3 tool steel for the first time. In the experiments, the influence of the particles and the laser parameters (pulse power, pulse duration and focal diameter) on the material properties of the localized dispersed zones was studied by optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The composite´s (micro-) hardness was measured and calculated by using a rule of mixture. Additionally, the influence of the laser parameters and the TaC particles on the geometrical properties of the implants was studied by optical microscopy and white light interferometry. The results showed that defect-free implants with hardness values of ~900 HV1 can be obtained at the focal spot, since a localized dispersing of the TaC particles is possible using a pulsed millisecond laser. However, in dependence of the laser intensity, also a partial dissolution of the initial particles occurs. This leads to the precipitation of new dendritic TaC nanoparticles and to varying contents of retained austenite in the matrix. Both effects have a strong influence on the implant hardness and must be considert by the rule of mixture. Regarding the geometrical response it was pointed out that protruded microfeatures with heights up to 10 µm can be created. In comparison to laser remelted zones, the implanted zones showed significantly altered weld pool profiles due to the influence of the particles on the melt convection. A transition of the implant shape from predominantly dome-shaped to predominantly ring-shaped was observed for intensities >1.7∙106 W/cm2 due to the onset of the keyhole effect. KW - Laser implantation KW - Surface texturing KW - TaC KW - Tantalum carbide KW - Hot-Stamping KW - X38CrMoV5-3 KW - Localized Laser Dispersing PY - 2019 U6 - https://doi.org/10.1007/s40516-019-00106-x SN - 2196-7229 VL - 2019 IS - First Online SP - 1 EP - 22 PB - Springer Nature Switzerland AG. Part of Springer Nature. AN - OPUS4-50041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fritzsche, André A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - Influence of welding parameters on electromagnetic supported degassing of die-casted and wrought aluminum N2 - The paper describes a systematic investigation of the EM influenced laser beam welding of the aluminum die casting alloy AlSi12(Fe) in comparison to a reference material, a wrought aluminum alloy AlMg3. By using of a face centred CCD test plan, the influencing variables laser power, welding velocity and magnetic flux density are varied with regard to their influence on the remaining porosity. The global pore fraction of the weld seams was analyzed by X-ray images with ImageJ. This enabled a qualitatively very good regression model to be derived for the respective material, which identifies the dominant influencing variables. The results prove, statistically verified, for the investigated parameter range, that - the magnetic flux density is the main cause for the porosity reduction, - the porosity rises with increasing laser power the porosity in the weld seams rises, - the influence of the welding velocity is negligible, - the pore quantity in wrought alloy is more strongly minimized by the magnetic flux density than in die casting, - the porosity decreases due to the EM influence by approx. 70 % compared to the unaffected welds. This effect is emphasized by the contour line charts, which illustrate the relationship between laser power and magnetic flux density. With the exception of the quadratic influence of B at the wrought alloy, the statistical correlation shows a linear development of the respective influence variables for both aluminum alloys. In order to investigate these deviations, further simulations with a focus on weld pool geometry and weld pool flow are to be performed. In addition, the welding results can be classified in accordance with DIN EN ISO 13919-2 in the highest evaluation group B for AlMg3 and in evaluation group C for AlSi12(Fe) by applying a magnetic flux density of 350 mT. The analysis of the CT images at constant laser power and welding velocity allows a direct comparison both between the two alloys and also as a function of the magnetic flux density with regard to the number and size of pores. An increase in the magnetic flux density leads to a significant decrease in the number and volume of pores, which can be seen more clearly in wrought alloy than in die casting. Very acceptable results can be achieved for both materials and different welding parameters. This successfully demonstrates the desired process robustness and functionality of the EM system for practical applications. For subsequent investigations of overlap joints, the lowest possible laser power and a high magnetic flux density are recommended. T2 - 38th International Congress on Applications of Lasers & Electro-Optics CY - Orlando, FL, USA DA - 07.10.2019 KW - AISI D2 KW - Laser implantation KW - Surface texturing KW - TiB2 PY - 2019 SN - 978-1-940168-1-42 SP - Paper Macro 1202 AN - OPUS4-50009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zocca, Andrea A1 - Lüchtenborg, Jörg A1 - Mühler, T. A1 - Wilbig, Janka A1 - Mohr, Gunther A1 - Villatte, T. A1 - Léonard, Fabien A1 - Nolze, Gert A1 - Sparenberg, M. A1 - Melcher, J. A1 - Hilgenberg, Kai A1 - Günster, Jens T1 - Enabling the 3D Printing of Metal Components in μ-Gravity N2 - As humanity contemplates manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments to safely work in space for years. The supply of spare parts for repair and replacement of lost equipment will be one key need, but in-space manufacturing remains the only option for a timely supply. With high flexibility in design and the ability to manufacture ready-to-use components directly from a computeraided model, additive manufacturing (AM) technologies appear extremely attractive. For the manufacturing of metal parts, laser-beam melting is the most widely used AM process. However, the handling of metal powders in the absence of gravity is one prerequisite for its successful application in space. A gas flow throughout the powder bed is successfully applied to compensate for missing gravitational forces in microgravity experiments. This so-called gas-flow-assisted powder deposition is based on a porous Building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump. KW - Additive manufacturing KW - µ-gravity KW - Laser beam melting KW - Parabolic flight KW - 3D printing PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-492190 SP - 1900506 PB - WILEY-VCH Verlag GmbH AN - OPUS4-49219 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fritzsche, André A1 - Hilgenberg, Kai A1 - Rethmeier, Michael T1 - Elektromagnetische Porenreduktion beim Laserstrahlschweißen von Aluminium-Druckgusslegierungen N2 - Innerhalb der vorliegenden Untersuchung wurde ein elektromagnetisches Schmelzbadbeeinflussungssys-tem zur Reduktion des Porenanteils beim Laserstrahlschweißen von Aluminium-Druckguss verwendet. Hierbei wird der Unterschied der elektrischen Leitfähigkeiten zwischen Gas- bzw. Lufteinschlüssen und geschmolzenem Aluminium gezielt genutzt, um die im Schmelzbad eingeschlossenen Poren während des Laserstrahlprozesses zur Oberfläche zu verdrängen. Die dafür erforderlichen Lorentzkräfte werden durch ein oszillierendes Magnetfeld erzeugt. Bei den Laserstrahlschweißversuchen handelt es sich um Ein-schweißungen in Wannenlage (PA-Position) von 6 mm dickem Aluminium-Druckguss AC-AlSi9MnMg. Über einen zuvor optimierten Laserschweißprozess wurde durch zusätzlichen Einsatz eines elektromag-netischen Feldes dessen Wirkung hinsichtlich des Porengehaltes und der Oberflächenrauheit untersucht. Die Auswertung der Schweißnähte erfolgte anhand von Querschliffaufnahmen, Röntgenbildern sowie Computer-Tomographie (CT) Aufnahmen. In Abhängigkeit von der verwendeten magnetischen Fluss-dichte konnte eine Reduktion des Porenanteils von bis zu 75 % erzielt werden, wobei vor allem großvolu-mige Poren erfolgreich aus dem Schmelzbad entfernt werden konnten. Zudem konnte eine Reduktion der Oberflächenrauigkeit von ebenfalls bis zu 75 % erreicht werden. T2 - Assistentenseminar 2017 der Wissenschaftlichen Gesellschaft Fügetechnik e.V. im DVS CY - Rabenau bei Dresden, Sachsen, Germany DA - 06.09.2017 KW - Laserstrahlschweißen KW - Aluminium-Druckguss KW - Auftriebskräfte KW - Elektromagnetische Porenreduktion PY - 2019 SN - 978-3-96144-028-3 VL - 342 SP - 103 EP - 110 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-47622 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spranger, Felix A1 - Hilgenberg, Kai T1 - Dispersion behavior of TiB2 particles in AISI D2 tool steel surfaces during pulsed laser dispersing and their influence on material properties N2 - AISI D2 is one of the most applied cold-working tool steel for deep drawing operations, due to the materials good toughness and high wear resistance. However, since the lubricant-free deep drawing as well as the processing of high strength and ultra-high strength steel sheets remaining ongoing trends in the automotive industry, the tool surfaces need to be improved regarding their friction and wear behavior. For this purpose elevated micro textures can be applied. Since protruded micro features are predominantly affected by wear, a structuring process enabling the formation of suitable textures with high wear resistance is needed. In this paper surface texturing at microscale was conducted by laser implantation. This technique allows the fabrication of highly wear resistant, separated and elevated features (implants) on steel surfaces via a discontinuous dispersing of ceramic particles by pulsed laser radiation. The aim of this study was to investigate the techniques potential for the creation of wear resistant elevated micro features on AISI D2 tool steel surfaces by the application of TiB2 particles. The laser parameters (pulse power and length) were varied and a comparative material analysis on AISI D2 laser remelted spots and TiB2 localized dispersed zones was examined. High-speed camera recordings allowed the description of the particle insertion mechanism from pre-coatings during laser processing. Mechanical properties were analyzed by (micro-) hardness measurements at top and cross sections. The microstructure was investigated by optical microscopy, scanning electron microscopy (SEM), energy dispersive Xray spectroscopy (EDX) and X-ray diffraction (XRD). The implants geometrical properties (diameter, height, depth) were investigated by white light interferometry and optical microscopy. The experiments reveal that a pulsed laser remelting of AISI D2 leads to a significant hardness drop due to high retained austenite (γR) contents. Contrary, a localized dispersing of TiB2 particles leads to defect free dome- or ring-shaped elevated features with hardness values up to 1800 HV1. The high hardness values result from the dispersed TiB2 particles and an in-situ precipitation of new hard particle phases, which lead to a reduction of the γR content within the matrix. KW - Laser dispersing KW - Laser implantation KW - AISI D2 KW - TiB2 PY - 2019 U6 - https://doi.org/10.1016/j.apsusc.2018.10.179 IS - 467-468 SP - 493 EP - 504 PB - Elsevier B.V. AN - OPUS4-46391 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 ent-scheidende 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 Oberflächenstrukturierun-gen 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 er-habener Strukturen momentan limitiert, so dass in der Regel zusätzliche verschleißreduzierende Be-schichtungen notwendig werden. In diesem Beitrag wurde das Verfahren der Laserimplantation angewandt, mit dem erhabene und sepa-rierte 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 Titandibo-rid 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 Puls-leistung und Pulsdauer zu steuern. T2 - 38. Assistentenseminar Füge- und Schweißtechnik CY - Rabenau, Germany DA - 06.10.2017 KW - Laserimplantation PY - 2019 UR - https://www.dvs-media.eu/de/neuerscheinungen/3646/38.-assistentenseminar-fuegetechnik SN - 978-3-96144-028-3 VL - 342 SP - 24 EP - 34 PB - DVS Media GmbH CY - Düsseldorf AN - OPUS4-47637 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hilgenberg, Kai A1 - Daum, Werner A1 - Maierhofer, Christiane A1 - Altenburg, Simon A1 - Bruno, Giovanni A1 - Heckel, Thomas A1 - Skrotzki, Birgit A1 - Zerbst, Uwe A1 - Kranzmann, Axel A1 - Bettge, Dirk A1 - Sommer, Konstantin A1 - Seeger, Stefan A1 - Nitsche, Michael A1 - Günster, Jens A1 - Evans, Alexander T1 - Additive manufacturing at the BAM: We focus on Safety N2 - In Germany, the Federal Institute for Materials Research and Testing (BAM) is addressing challenges in the implementation of additive manufacturing on the industrial landscape for safety-critical applications. KW - Process development KW - Additive Manufacturing KW - In-situ Process Monitoring KW - Non-destructive Materials KW - Characterisation KW - Safety KW - Fatigue KW - Environment KW - Standardisation PY - 2019 UR - https://static.asminternational.org/amp/201910/22/ SN - 0882-7958 VL - 177 IS - 7 SP - 22 EP - 26 PB - ASM International CY - Materials Park, OH, USA AN - OPUS4-49780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -