TY - JOUR A1 - Kubaschinski, Paul A1 - Gottwalt, Albin A1 - Tetzlaff, Ulrich A1 - Altenbach, Holm A1 - Waltz, Manuela T1 - Calibration of a combined isotropic-kinematic hardening material model for the simulation of thin electrical steel sheets subjected to cyclic loading T1 - Kalibrierung eines Materialmodells für die Simulation von zyklisch beanspruchten dünnen Elektroblechen unter Berücksichtigung kombinierter isotroper-kinematischer Verfestigung JF - Materials Science & Engineering Technology JF - Materialwissenschaft und Werkstofftechnik N2 - The combined isotropic-kinematic hardening model enables the description of the cyclic transient elastic-plastic material behaviour of steel. However, the determination of the material model parameters and understanding of their influence on the material response can be a challenging task. This study deals with the individual steps of the material model calibration for the simulation of thin electrical steel sheets under cyclic loading. Specific recommendations are made for the determination of kinematic and isotropic hardening material parameters. In particular, the isotropic hardening evolution is described by Voce's exponential law and a simple multilinear approach. Based on the multilinear approach, which allows for different slopes in the evolution of the yield surface size, an alternative calibration of the isotropic hardening component is proposed. As a result, the presence of the yield plateau in the first half cycle can be accurately captured, while convergence issues in the material model definition for numerical simulations can be avoided. The comparison of simulated load cycles with experimental cyclic tests shows a good agreement, which indicates the suitability of the proposed material model calibration for electrical steel. N2 - Die Berücksichtigung kombinierter isotroper-kinematischer Verfestigung ermöglicht die Beschreibung und Modellierung des transienten elastisch-plastischen Werkstoffverhaltens von Stahl. Die Ermittlung der zugrunde liegenden Materialparameter und das Verständnis für deren Einfluss auf die Materialantwort stellt jedoch häufig eine anspruchsvolle Aufgabe dar. In der vorliegenden Arbeit wird auf die einzelnen Schritte bei der Kalibrierung des Materialmodells im Rahmen einer Simulation von zyklisch beanspruchten dünnen Elektroblechen eingegangen. Dabei werden konkrete Empfehlungen für die Ermittlung der kinematischen und isotropen Verfestigungsparameter gegeben. Die Evolutionsgleichung der isotropen Verfestigung wird sowohl durch einen Exponentialansatz nach Voce als auch durch einen einfachen multilinearen Ansatz beschrieben. Basierend auf dem multilinearen Ansatz, der unterschiedliche Steigungen in der Evolution der Fließfläche ermöglicht, wird eine alternative Kalibrierung der isotropen Komponente vorgeschlagen. Dadurch kann das auftretende Fließplateau im ersten Halbzyklus präzise erfasst werden, während Konvergenzprobleme des Materialmodells vermieden werden. Der Vergleich von simulierten Belastungszyklen mit experimentellen Daten zeigt eine gute Übereinstimmung, was für die Eignung des vorgeschlagenen Kalibrierungsprozesses für Elektroblech spricht. UR - https://doi.org/10.1002/mawe.202100341 KW - cyclic plasticity KW - material model KW - combined hardening KW - finite-element simulation KW - electrical steel KW - zyklische Plastizität KW - Materialmodell KW - kombinierte Verfestigung KW - Finite-Elemente-Simulation KW - Elektroblech Y1 - 2022 UR - https://doi.org/10.1002/mawe.202100341 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-22478 SN - 1521-4052 VL - 53 IS - 4 SP - 422 EP - 439 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Kiehl, Maximilian A1 - Scheid, Adriano A1 - Graf, Karin A1 - Ernst, Benedikt A1 - Tetzlaff, Ulrich T1 - Coaxial laser cladding of cobalt-base alloy Stellite™ 6 on gray cast iron/investigations on friction, wear versus commercial brake pad, and corrosion characteristics JF - Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering UR - https://doi.org/10.1177/09544070221145512 Y1 - 2023 UR - https://doi.org/10.1177/09544070221145512 SN - 2041-2991 SN - 0954-4070 VL - 237 IS - 14 SP - 3285 EP - 3303 PB - Sage CY - London ER - TY - JOUR A1 - Ernst, Benedikt A1 - Keim, Simon A1 - Tetzlaff, Ulrich T1 - On the anisotropic indentation modulus and anisotropic creep behavior of β-Sn characterized by nanoindentation methods JF - Materials Science and Engineering: A UR - https://doi.org/10.1016/j.msea.2022.143392 Y1 - 2022 UR - https://doi.org/10.1016/j.msea.2022.143392 SN - 1873-4936 SN - 0921-5093 VL - 2022 IS - 848 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Handwerker, Michael A1 - Kessler, Jörg A1 - Marzbani, Hormoz A1 - Tetzlaff, Ulrich T1 - Pressure and heat treatment of continuous fibre reinforced thermoplastics produced by fused filament fabrication JF - Progress in Additive Manufacturing N2 - Fused filament fabrication allows for the additive manufacturing of complex geometries without requiring moulds. However, due to large air voids and poor layer adhesion, the mechanical properties of parts manufactured using fused filament fabrication lag behind those of parts manufactured using conventional techniques. A previous study found that the tensile strength and Young’s modulus of such parts could be increased by a heat-treatment process. However, large air voids were still present after annealing. This study, therefore, investigates the influence of a post-pressure-treatment process on the mechanical performance and the air void ratio of continuous glass fibre-reinforced polyamide 6 in the directions perpendicular to the fibres. Without the treatment, Young’s modulus on the plane parallel to the printing bed is eight times higher than Young’s modulus perpendicular to it. Annealing at 1 MPa homogenises the material and leads to a significant increase of both the tensile strength (55 MPa) and Young’s modulus (5 GPa). Increasing the pressure to 3 MPa only slightly increases the mechanical performance, whereas a further increase to 6 MPa causes no significant changes. UR - https://doi.org/10.1007/s40964-022-00315-5 KW - Pressure treatment KW - Fused filament fabrication KW - Continuous glass fibre KW - Polyamide 6 Y1 - 2022 UR - https://doi.org/10.1007/s40964-022-00315-5 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-31239 SN - 2363-9520 SN - 2363-9512 VL - 8 IS - 2 SP - 99 EP - 116 PB - Springer CY - Cham ER - TY - JOUR A1 - Lemos, Georges A1 - Fredel, Márcio Celso A1 - Pyczak, Florian A1 - Tetzlaff, Ulrich T1 - Creep resistance improvement of a polycrystalline Ni-based superalloy via TiC particles reinforcement JF - Materials Science and Engineering: A UR - https://doi.org/10.1016/j.msea.2022.143821 Y1 - 2022 UR - https://doi.org/10.1016/j.msea.2022.143821 SN - 1873-4936 SN - 0921-5093 VL - 2022 IS - 854 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Volpato, Guilherme A1 - Tetzlaff, Ulrich A1 - Fredel, Márcio Celso T1 - A comprehensive literature review on laser powder bed fusion of Inconel superalloys JF - Additive Manufacturing UR - https://doi.org/10.1016/j.addma.2022.102871 KW - Inconel 718 KW - Inconel 625 KW - Laser powder bed fusion KW - Selective laser melting KW - Additive manufacturing Y1 - 2022 UR - https://doi.org/10.1016/j.addma.2022.102871 SN - 2214-7810 SN - 2214-8604 VL - 2022 IS - 55 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Ernst, Benedikt A1 - Kubaschinski, Paul A1 - Schiessl, Andreas A1 - Waltz, Manuela A1 - Höppel, Heinz Werner A1 - Tetzlaff, Ulrich T1 - Comparison of the Young’s modulus of the lead free solder alloy Sn-Ag3.8-Cu0.7 determined by hot tensile tests, ultrasonic measurements and 𝛽-Sn single crystal calculations JF - Materials Science and Engineering: A N2 - Sn-based solders are known for their tendency to form coarse grained microstructures. In combination with the high elastic anisotropy of 𝛽-Sn, the overall elastic properties and their interpretation require a careful discussion of the structure–property-relationship as elastic constants are often important input parameters for creep or fatigue models. This study therefore investigates the influence of microstructure and testing method on the Young’s modulus E for the widespread lead free solder alloy Sn-Ag3.8-Cu0.7 (SAC387) using bulk specimens. Due to its already high homologous temperature at room temperature (Thom ≈ 0.6 = T/Tm for Tm being the melting temperature), hot tensile tests generally bear the risk of superimposed creep deformation. Mechanical testing becomes even more challenging, since yield strengths are usually low for these alloys. Consequently, in addition to the hot tensile tests executed for the engineering strain rate 𝜖̇𝑒 = 1 ⋅ 10−3 s−1, two supplemental methods are used to determine the Young’s modulus comprising of the dynamic resonance frequency measurement and the calculation of the Young’s modulus based on single crystal compliance data of the majority phase 𝛽-Sn.Young’s moduli yielded from dynamic resonance frequency measurement and calculations based on single crystal compliance data showed comparable results of (E35 ◦C ≈ 55 GPa, E80 ◦C ≈ 51 GPa and E125 ◦C ≈ 48 GPa). Hot tensile tests showed similar data with the largest deviation at 80 ◦C, where E80 ◦C ≈ 53 GPa was determined. These absolute values and their temperature dependence can be attributed to the microstructure of the cast specimens which show a general preferred orientation of 𝛽-Sn grains close to <110> after analysis via electron backscattered diffraction (EBSD). A comparison with literature data revealed significant differences in the Young’s moduli which are likely to be attributed to differences in the preferred orientation of 𝛽-Sn grains. UR - https://doi.org/10.1016/j.msea.2024.147354 Y1 - 2024 UR - https://doi.org/10.1016/j.msea.2024.147354 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-52143 SN - 1873-4936 SN - 0921-5093 VL - 2024 IS - 916 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Gottwalt, Albin A1 - Kubaschinski, Paul A1 - Waltz, Manuela A1 - Tetzlaff, Ulrich T1 - Influence of the cutting method on the fatigue life and crack initiation of non-oriented electrical steel sheets JF - International Journal of Fatigue N2 - The fatigue behavior of thin electrical steel sheets under cyclic loading is investigated in dependence on the edge surface. Therefore, four different edge conditions are compared, whereas the edge is either laser cut, shear cut, wire cut, or polished. Strain- and stress-controlled fatigue tests are performed to determine S-N curves in the low cycle regime as well as in the high cycle regime. Microstructural data is collected by non-contacting (optical) Profilometry, Nanoindentation, X-Ray Diffraction, and Electron Backscatter Diffraction to understand the differences in fatigue life by considering surface roughness, residual stresses, hardness, and microstructure. Shear cut specimens achieve the lowest fatigue life, while the other edge conditions reach relatively similar values in the LCF regime. Crack initiation is mainly intergranular in the case of defect-free edges. This tendency has a considerable influence on the observed fatigue behavior. UR - https://doi.org/10.1016/j.ijfatigue.2023.108073 Y1 - 2023 UR - https://doi.org/10.1016/j.ijfatigue.2023.108073 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-46260 SN - 1879-3452 SN - 0142-1123 VL - 2024 IS - 180 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Gottwalt, Albin A1 - Kubaschinski, Paul A1 - Waltz, Manuela A1 - Völkl, Rainer A1 - Glatzel, Uwe A1 - Tetzlaff, Ulrich T1 - Cyclic deformation behavior of non-oriented electrical steel sheets JF - Materials Science and Engineering: A UR - https://doi.org/10.1016/j.msea.2023.145684 Y1 - 2023 UR - https://doi.org/10.1016/j.msea.2023.145684 SN - 0921-5093 SN - 1873-4936 VL - 2023 IS - 886 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Vieweger, Daniel A1 - Diel, Sergej A1 - Schweiger, Hans-Georg A1 - Tetzlaff, Ulrich T1 - Mechanical Properties of Raw Filaments and Printed Specimens: Effects of Fiber Reinforcements and Process Parameters JF - Polymers N2 - Fused Deposition Modeling (FDM) is a well-established manufacturing method for producing both prototype and functional components. This study investigates the mechanical properties of FDM components by material and process-related influencing variables. Tensile tests were conducted on seven different materials in their raw filament form, two of which were fiber-reinforced, to analyze their material-related influence. To cover a wide range from standard to advanced materials relevant for load-carrying components as well as their respective variations, polylactic acid (PLA), 30% wood-fiber-reinforced PLA, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), a blend of ABS and PC, Nylon, and 30% glass-fiber-reinforced Nylon were selected. The process-related influencing variables were studied using the following process parameters: layer thickness, nozzle diameter, build orientation, nozzle temperature, infill density and pattern, and raster angle. The first test series revealed that the addition of wood fibers significantly worsened the mechanical behavior of PLA due to the lack of fiber bonding to the matrix and significant pore formation. The polymer blend of ABS and PC only showed improvements in stiffness. Significant strength and stiffness improvements were found by embedding glass fibers in Nylon, despite partially poor fiber–matrix bonding. The materials with the best properties were selected for the process parameter analysis. When examining the impact of layer thickness on part strength, a clear correlation was evident. Smaller layer thicknesses resulted in higher strength, while stiffness did not appear to be affected. Conversely, larger nozzle diameters and lower nozzle temperatures only positively impacted stiffness, with little effect on strength. The part orientation did alter the fracture behavior of the test specimens. Although an on-edge orientation resulted in higher stiffness, it failed at lower stresses. Higher infill densities and infill patterns aligned with the load direction led to the best mechanical results. The raster angle had a significant impact on the behavior of the printed bodies. An alternating raster angle resulted in lower strengths and stiffness compared to a unidirectional raster angle. However, it also caused significant stretching due to the rotation of the beads. UR - https://doi.org/10.3390/polym16111576 Y1 - 2024 UR - https://doi.org/10.3390/polym16111576 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-48595 SN - 2073-4360 VL - 16 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Gottwalt, Albin A1 - Kubaschinski, Paul A1 - Waltz, Manuela A1 - Tetzlaff, Ulrich T1 - Influence of Subsequent Heat Treatment on Fatigue Behavior of Shear-Cut Electrical Steel Sheets JF - Alloys N2 - The fatigue behavior of a fully processed, non-oriented electrical steel sheet is investigated in dependence on shear-cutting parameters and a subsequent heat treatment. For this, stress-controlled fatigue tests are performed before and after annealing at 700 °C for a total of six different shear-cutting settings. For all parameters, the fatigue strength of shear-cut sheets is improved by the heat treatment. This is due to reduction in a large part of the strain hardening region as well as the reduction in tensile residual stresses. Both were introduced during shear cutting and act detrimental to the fatigue strength. However, the intensity of this improvement depends on the shear-cutting parameters. This is related to the corresponding edge surfaces characteristically being formed during shear cutting. Specimens cut with a worn cutting tool show a more pronounced increase in fatigue life. In contrast, specimens produced with a sharp-edged cutting tool and high cutting clearance hardly benefit from the heat treatment. This appears to be caused by differences in surface topography, in particular coarse topographical damage in the form of grain breakouts. If these occur during shear cutting, the crack formation is not significantly delayed by additional annealing. UR - https://doi.org/10.3390/alloys3040017 Y1 - 2024 UR - https://doi.org/10.3390/alloys3040017 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-53767 SN - 2674-063X VL - 3 IS - 4 SP - 281 EP - 294 PB - MDPI CY - Basel ER - TY - JOUR A1 - de Souza Pinto Pereira, Adriano A1 - Gutjahr, Jhonattan A1 - Pereira, Milton A1 - Tetzlaff, Ulrich A1 - Fredel, Márcio Celso T1 - Processability of thin-powdered Inconel X750 and TiC metal matrix composite by laser-directed energy deposition JF - Journal of Laser Applications UR - https://doi.org/10.2351/7.0001134 KW - metal matrix composites KW - directed energy deposition KW - laser materials processing KW - Ni-base superalloys KW - particle reinforcement KW - microstructural characterization Y1 - 2023 UR - https://doi.org/10.2351/7.0001134 SN - 1042-346X SN - 1938-1387 N1 - Paper published as part of the special topic on Proceedings of the International Congress of Applications of Lasers & Electro-Optics 2023 VL - 35 IS - 4 PB - LIA CY - Orlando ER - TY - CHAP A1 - Mohd, Zubair Akhtar A1 - Kreiner, Christian A1 - Schmid, Maximilian A1 - Zippelius, Andreas A1 - Tetzlaff, Ulrich A1 - Elger, Gordon T1 - Fully Connected Neural Network (FCNN) Based Validation Framework for FEA Post Processing to Improve SAC Solder Reliability Analysis T2 - 2024 IEEE 10th Electronics System-Integration Technology Conference (ESTC), Proceedings UR - https://doi.org/10.1109/ESTC60143.2024.10712023 Y1 - 2024 UR - https://doi.org/10.1109/ESTC60143.2024.10712023 SN - 979-8-3503-9036-0 PB - IEEE CY - Piscataway ER - TY - JOUR A1 - Gulden, Florian A1 - Gramstat, Sebastian A1 - Stich, Anton A1 - Hoppel, Heinz Werner A1 - Tetzlaff, Ulrich T1 - Properties and Limitation of an Oxide Coated Aluminum Brake Rotor JF - SAE Technical Paper UR - https://doi.org/10.4271/2018-01-1877 Y1 - 2018 UR - https://doi.org/10.4271/2018-01-1877 SN - 0148-7191 SN - 2688-3627 PB - SAE CY - Warrendale ER - TY - JOUR A1 - Volpato, Guilherme A1 - de Souza Pinto Pereira, Adriano A1 - Neumeier, Steffen A1 - Hotza, Dachamir A1 - Göken, Mathias A1 - Tetzlaff, Ulrich A1 - Fredel, Márcio Celso T1 - Influence of a Standard Heat Treatment on the Microstructure and Properties of Inconel X‐750 Produced by Laser Powder Bed Fusion JF - Advanced Engineering Materials N2 - The production of nickel‐base superalloys through powder bed fusion using a laser beam (PBF‐LB) offers a promising method for reducing the cost of aeronautical components, especially those with complex geometries. However, when these materials are processed using PBF‐LB, the standard heat treatments developed for conventional manufacturing routes do not consistently yield predictable microstructures or mechanical properties. Thus, this study analyzes how PBF‐LB affects the microstructure and mechanical behavior of Inconel alloy X‐750 when compared to a hot‐rolled counterpart after undergoing a standard precipitation‐hardening heat treatment (solution annealing, stabilization, and precipitation). Microstructure is examined using analytical electron microscopy and high‐energy X‐ray diffraction, while mechanical behavior is assessed through microhardness. Significant differences between both manufacturing routes are detected, so that PBF‐LB processing led to an increase in grain size, anisotropy, fraction of low‐angle grain boundaries, mean angle of misorientation, and dislocation density. Moreover, PBF‐LB promoted the formation of γ′‐Ni3(Al,Ti) and η‐Ni3Ti phases during solution annealing and stabilization, respectively. Notably, the formation of γ′ contributes to an anomalous microhardness increase observed between these steps. These findings suggest that PBF‐LB may inhibit recrystallization and facilitate precipitation during heat treatment, thereby affecting the performance of components produced using this technology. UR - https://doi.org/10.1002/adem.202500306 Y1 - 2025 UR - https://doi.org/10.1002/adem.202500306 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-67931 SN - 1527-2648 VL - 27 IS - 24 PB - Wiley CY - Weinheim ER -