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 - Charmi, Amir T1 - Mechanical anisotropy of additively manufactured stainless steel 316l: an experimental and numerical study N2 - This work aims for a yield function description of additively manufactured (AM) parts of stainless steel 316L at the continuum-mechanical macro-scale by means of so-called virtual experiments using a crystal plasticity model at meso-scale. T2 - 1st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing CY - BAM, Berlin DA - 10.12.2020 KW - Anisotropy KW - Crystal plasticity KW - Additive manufacturing PY - 2020 AN - OPUS4-51941 LA - eng 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 - CONF A1 - Carstensen, Niels T1 - Generation of Tribosystems by Additive Surface Treatment on Tool Steel Substrate N2 - Laser implantation aims at reducing friction and wear on highly stressed surfaces in forming processes. Especially the hot stamping process that is used as a resource efficient process for manufacturing geometrical complex and high-strength structures, exhibits severe wear and high friction during the forming operation. The laser implantation process addresses this problem by combining two different approaches (surface modification and surface structuring) in surface technology by creating elevated, highly wear-resistant micro-features to influence the tribological performance. Pure TiB2 implants have shown to reduce tool-sided wear significally and improve the part formability by reducing local necking in deep drawing tests. Within the scope of this work, TiB2-TiC and TiB2-TaC hard material mixtures are implanted on X38CrMoV5-3 hot work tool steel. The aim is to investigate how the implant material properties can be influenced by the application of different mixing ratios of hard material mixtures under the specific variation of the process parameters. Distinct implant formations are tested on a novel test apparatus to examine the influence on the tribological properties. From the analyses of the implant properties by hardness measurements, light microscopic images, EDX and XRD analyses process parameter ranges are identified to produce defect-free dome- and ring-shaped implants. The specific process parameters (pulse power, pulse duration, mixing ratio and coating thickness) can be used for the determination of the implant geometry (height, width and depth). The tribological tests exhibit improved friction and wear properties. Based on these results, a tribosystem manufactured by this additive surface treatment technology shows great potential to enhance the effectiveness of the hot stamping process. T2 - Friction 2021 CY - Sankt Augustin, Germany DA - 18.11.2021 KW - Laser implantation KW - Surface modification KW - Additive surface treatment KW - Hot stamping KW - Tool steel PY - 2021 AN - OPUS4-53809 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kempf, A. 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 - 2021 AN - OPUS4-53792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Çağtay T1 - WelDX – progress report on the welding data exchange format N2 - The presentation shows the current development status of the Welding Data Exchange (weldx) format based on the Advanced Scientific Data Format (ASDF). The use of a complete single pass arc welding experiment example stored in a single weldx file and validated against a predefined schema definition is presented. The example includes generic experimental metadata, the workpiece geometry and materials definition following associated standards, the weld process spatial movement description, the welding process parameter descriptions and welding process measurements. The inclusion of 3D scan data of the workpiece description is also included. The full code and data is available on GitHub: https://github.com/BAMWelDX/IIW2021_joint_intermediate_CXII T2 - IIW joint intermediate meeting Comm. I,IV,XII,SG212 2021 CY - Online meeting DA - 30.03.2021 KW - WelDX KW - Research data management KW - Open science KW - Arc welding KW - Digitalization PY - 2021 AN - OPUS4-52661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ehlers, Henrik T1 - Online ET with MR Sensor Arrays for LPBF Parts N2 - In this presentation we discuss the online monitoring of LPFB parts using eddy current testing with magenoresistive sensor arrays. The underlying principle, the developed hardware and the results of the firt online monitoring are described in the presentation. T2 - 2. Online-Workshop "In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys " CY - Online meeting DA - 19.04.2021 KW - Eddy current testing KW - LPBF KW - GMR KW - SLM KW - Haynes282 KW - Additive manufacturing PY - 2021 AN - OPUS4-52700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abdel-Wakil, W. A1 - Fahmy, Alaa A1 - Kamoun, E. A1 - Hassan, W. A1 - Abdelhai, Q. A1 - Salama, T. T1 - A New Route for Synthesis of Polyurethanevinyl Acetate Acrylate Emulsions as Binders for Pigment Printing of Cotton Fabrics N2 - Herein, two polyurethane oligomers were successfully synthesized using a prepolymer mixing process. The prepolymers were synthesized based on the step-growth addition polymerization of polypropylene glycol, Methylene diphenyl diisocyanate and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Isopropanol was functioned as the isocyanate blocking agent. Thereafter, different terpolymer emulsions were prepared by the emulsion graft copolymerization with the vinyl acetate monomer in presence of 2-ethylhexyl acrylate as a vinyl monomer. The chemical structures of the synthesized oligomeric monomers were probed by FTIR spectroscopy and found to vary with the content of acrylic monomer used in the oligomer synthesis phase (i.e.hydroxyethyl acrylate or hydroxyethyl methacrylate). The topography, thermal stability, and particle size of terpolymers were investigated by SEM, TGA, and zeta potential, respectively. The TGA results demonstrated marked enhancement in thermal stability of the synthesized terpolymers up to ca. 600°C, which was concurrent with enhanced surface homogeneity and film properties as evidenced by the SEM images. These terpolymers showed also property enhancement as binders for textile pigment printing in terms of rubbing resistance, color strength and fastness to washing when compared to the commercial binders. These judgments would provide a new competent synthesis route by introducing polyurethane acetate vinyl acrylate as the binder for use in pigment printing of cotton fabrics. KW - Vinyl monomer KW - Polyurethane acetate vinyl acrylate KW - Surface coating KW - Terpolymer KW - Textile binder PY - 2020 DO - https://doi.org/10.21608/ejchem.2020.21712.2292 VL - 63 IS - 3 SP - 1063 EP - 1073 AN - OPUS4-52300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werner, Tiago T1 - Short fatigue crack propagation in additively manufactured stainless steel 316L N2 - Fracture mechanics is a key to fatigue assessment in AM metal components. Short fatigue cracks are initiated at defects and pronounced surface roughness intrinsic to AM. The subsequent crack-propagation is strongly influenced by microstructural interactions and the build-up of crack-closure. The aim of the present study is to give an insight into short-crack propagation in AM-metals. Fatigue crack propagation resistance curves were determined experimentally for AISI 316L manufactured by Laser Powder Bed Fusion (L-PBF) which was heat treated at three different temperatures. Differences in the build-up of the fatigue-crack propagation threshold in between the L-PBF specimens and compared to wrought material are due to the residual stress states, a pronounced roughness of the crack-faces in the L-PBF specimens and phase transformation in the vicinity of the crack-tip, resulting in increased crack-closure. This, together with crack-branching found along the crack path, enhances the resistance to the propagation of fatigue cracks. T2 - In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys CY - Online meeting DA - 19.04.2021 KW - AM KW - Cyclic R-Curve KW - Fatigue Crack Propagation PY - 2021 AN - OPUS4-52587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Charmi, Amir T1 - Mechanical anisotropy of LPBF 316L: a modeling approach N2 - The underlying cause of mechanical anisotropy in additively manufactured (AM) parts is not yet fully understood and has been attributed to several different factors like microstructural defects, residual stresses, melt pool boundaries, crystallographic and morphological textures. To better understand the main contributing factor to the mechanical anisotropy of AM stainless steel 316L, bulk specimens were fabricated via laser powder bed fusion (LPBF). Tensile specimens were machined from these AM bulk materials for three different inclinations relative to the build plate. Dynamic Young's modulus measurements and tensile tests were used to determine the mechanical anisotropy. Some tensile specimens were also subjected to residual stress measurement via neutron diffraction, porosity determination with X-ray micro-computed tomography, and texture analysis with electron backscatter diffraction (EBSD). A crystal plasticity model was used to analyze the elastic anisotropy and the anisotropic yield behavior of the AM specimens, and it was able to capture and predict the experimental behavior accurately. Overall, it was shown that the mechanical anisotropy of the tested specimens was mainly influenced by the crystallographic texture. T2 - 2. Online-Workshop "In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys " CY - Online meeting DA - 20.04.2021 KW - Anisotropy KW - Crystal plasticity KW - Additive manufacturing PY - 2021 AN - OPUS4-52603 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -