@article{SchmittGottwaltWinkleretal.2021, author = {Schmitt, Matthias and Gottwalt, Albin and Winkler, Jakob and Tobie, Thomas and Schlick, Georg and Stahl, Karsten and Tetzlaff, Ulrich and Schlip, Johannes and Reinhart, Gunther}, title = {Carbon Particle In-Situ Alloying of the Case-Hardening Steel 16MnCr5 in Laser Powder Bed Fusion}, volume = {11}, pages = {11060896}, journal = {Metals}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2075-4701}, doi = {https://doi.org/10.3390/met11060896}, year = {2021}, abstract = {The carbon content of steel affects many of its essential properties, e.g., hardness and mechanical strength. In the powder bed fusion process of metals using a laser beam (PBF-LB/M), usually, pre-alloyed metal powder is solidified layer-by-layer using a laser beam to create parts. A reduction of the carbon content in steels is observed during this process. This study examines adding carbon particles to the metal powder and in situ alloying in the PBF-LB/M process as a countermeasure. Suitable carbon particles are selected and their effect on the particle size distribution and homogeneity of the mixtures is analysed. The workability in PBF-LB is then shown. This is followed by an evaluation of the resulting mechanical properties (hardness and mechanical strength) and microstructure in the as-built state and the state after heat treatment. Furthermore, potential use cases like multi-material or functionally graded parts are discussed.}, language = {en} } @article{GrafTetzlaffBiscaiadeSouzaetal.2018, author = {Graf, Karin and Tetzlaff, Ulrich and Biscaia de Souza, Gelson and Scheid, Adriano}, title = {Effect of Dilution on the Microstructure and Properties of CoCrMoSi alloy Coatings Processed on High-Carbon Substrate}, volume = {22}, pages = {e20180502}, journal = {Materials Research: Revista Ibero-Americana de Materiais}, number = {1}, publisher = {Associa{\c{c}}{\~a}o Brasileira de Metalurgia e Materiais (ABM); Associa{\c{c}}{\~a}o Brasileira de Cer{\^a}mica (ABC); Associa{\c{c}}{\~a}o Brasileira de Pol{\´i}meros (ABPol)}, address = {S{\~a}o Carlos}, issn = {1980-5373}, doi = {https://doi.org/10.1590/1980-5373-MR-2018-0502}, year = {2018}, abstract = {The Laves phase reinforced CoCrMoSi alloy system has emerged as a candidate material to protect the surface of components to withstand harsh environments under wear and/or corrosion. However, previous reports have raised some concerns and restricted a wider selection of iron-based substrates to be coated, especially limiting the carbon content. This work aims to outline the Laves - Carbides phases in the microstructure and its effect on the properties of T400 alloy deposited on GGG40 ductile iron. Dilution of 26 \% ensured Laves formation either as primary or secondary, due to high-silicon substrate selected. Departing from 41 \% dilution, the alloy changed to a completely carbide strengthened system. Therefore, for the lowest dilution the coatings hardness is dictated by Laves phase whereas, for higher ones, carbides are the most influent phases.}, language = {en} } @article{GottwaltKubaschinskiWaltzetal.2025, author = {Gottwalt, Albin and Kubaschinski, Paul and Waltz, Manuela and Tetzlaff, Ulrich}, title = {Influence of shear cutting parameters on the edge properties and the fatigue behavior of non-oriented electrical steel sheets}, volume = {56}, journal = {Materials Science \& Engineering Technology}, number = {4}, publisher = {Wiley}, address = {Weinheim}, issn = {0933-5137}, doi = {https://doi.org/10.1002/mawe.202400094}, pages = {537 -- 548}, year = {2025}, abstract = {The fatigue behavior of a fully processed, non-oriented electrical steel sheet is investigated for different shear cutting parameters. Therefore, three cutting clearances (15 μm, 35 μm and 50 μm) in combination with two different punching tool wear states (sharp and worn) are compared regarding their mechanical properties. For this purpose, surface measurements, nanoindentation tests and stress-controlled fatigue tests with a positive load ratio are performed for all six parameter sets. During shear cutting the material gets locally strain-hardened and a deformed surface with micro-notches is created. Compared to a polished reference condition, the fatigue strength of the shear-cut sheets is severely deteriorated. However, the intensity of deterioration varies depending on the shear cutting parameters. For small cutting clearances, the highest fatigue life is observed for a sharp cutting tool. In contrast, for medium and high cutting clearances, samples that are cut with a worn tool achieve higher fatigue lives. Surface characteristics in the fracture zone, which act as a failure-critical crack location, are considered as the main influencing factor.}, language = {en} } @article{KiehlScheidGrafetal.2022, author = {Kiehl, Maximilian and Scheid, Adriano and Graf, Karin and Ernst, Benedikt and Tetzlaff, Ulrich}, title = {Coaxial Laser Cladding of Cobalt-Base Alloy Stellite™ 6 on Grey Cast Iron Analysis of the Microstructural and Mechanical Properties Depending on the Laser Power}, volume = {32}, journal = {Journal of Materials Engineering and Performance}, number = {8}, publisher = {Springer}, address = {New York}, issn = {1544-1024}, doi = {https://doi.org/10.1007/s11665-022-07358-3}, pages = {3821 -- 3838}, year = {2022}, abstract = {A high-power diode laser was used to generate single- and multi-bead coatings of Stellite™ 6 by coaxial laser cladding over flat grey cast iron (EN-GJLP-200) as a preliminary study to develop a wear and corrosion resistant coating for brake disks on a cost-effective substrate. In this article, we have focused on a detailed quantitative analysis of the effect of different laser powers (1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 kW) on the bead geometry, dilution, microstructure, and hardness. Coatings dilution or composition depends directly on the laser power as well as bead geometry. The typical microstructure of the coatings comprises a solid solution of α (hcp)- and β (fcc)-Co with a dendritic structure as a metal matrix and an interdendritic lamellar eutectic, which contains predominantly β-Co, chromium carbides Cr7C3 and Cr23C6 as well as blocky tungsten carbide W2C. Coating hardness depends on the chemical composition and microstructure that is modified by the deposition parameters. Low laser power results in high carbide fraction and most refined microstructures, accounting for harder coatings.}, language = {en} } @article{GueldaliDeRoseMittagetal.2025, author = {G{\"u}ldali, Derya and De Rose, Angela and Mittag, Max and Gr{\"u}bel, Benjamin and Neuhaus, Holger and Tetzlaff, Ulrich}, title = {Interconnection of low-temperature metallization on silicon solar cells - The role of silver in tin-bismuth-based solder alloys}, volume = {2025}, pages = {113488}, journal = {Solar Energy Materials and Solar Cells}, number = {285}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-3398}, doi = {https://doi.org/10.1016/j.solmat.2025.113488}, year = {2025}, abstract = {This study investigates the potential of tin-bismuth (SnBi) alloys micro-alloyed with silver (Ag) to enhance low-temperature (LT) soldering for photovoltaic (PV) modules. The primary focus is on addressing challenges such as intermetallic compound (IMC) formation, which can compromise mechanical strength and durability under thermal cycling, thereby improving the long-term stability of solder joints. A systematic investigation of the influence of the Ag amount is being conducted with the intention to find the optimal alloy composition for SnBi solder joints on LT metallization contacts. The objective is to provide a cost-effective, lead-free alternative for the interconnection of temperature-sensitive solar cells like silicon heterojunction (SHJ) cells. The findings illustrate that the addition of 0.4 \%wt. Ag notably enhances the wettability and initial mechanical strength of the solder. An increase in the Ag content to 1.0 \%wt. results in an excessive growth of IMC, which in turn leads to increased brittleness and potential long-term stability issues of the solder joint. Thermal cycling tests demonstrate that modules soldered with SnBiAg0.4 exhibited less than -5 \% loss in power. This composition represents an optimal balance between performance and cost. These findings show the potential of SnBiAg0.4 as a suitable solder alloy regarding long-term stability and electrical performance for interconnection of LT metallization contacts of solar cells in PV module manufacturing.}, language = {en} } @article{VolpatodeSouzaPintoPereiraLemosetal.2023, author = {Volpato, Guilherme and de Souza Pinto Pereira, Adriano and Lemos, Georges and Schmitt, Matthias and Glatzel, Uwe and Pyczak, Florian and Tetzlaff, Ulrich and Fredel, M{\´a}rcio Celso}, title = {Out-of-Equilibrium Formation of Ni3Ti η-Phase in Inconel X-750 Produced via Laser Powder Bed Fusion and Spark Plasma Sintering}, volume = {54}, journal = {Metallurgical and Materials Transactions A: Physical metallurgy and materials science}, number = {5}, publisher = {Springer}, address = {Boston}, issn = {1073-5623}, doi = {https://doi.org/10.1007/s11661-022-06946-1}, pages = {1924 -- 1936}, year = {2023}, language = {en} } @article{VolpatodeSouzaPintoPereiraFredeletal.2024, author = {Volpato, Guilherme and de Souza Pinto Pereira, Adriano and Fredel, M{\´a}rcio Celso and Tetzlaff, Ulrich}, title = {On the Development of a Heat Treatment for Inconel Alloy X-750 Produced Using Laser Powder Bed Fusion}, volume = {55}, journal = {Metallurgical and Materials Transactions A: Physical metallurgy and materials science}, number = {11}, publisher = {Springer}, address = {Boston}, issn = {1073-5623}, doi = {https://doi.org/10.1007/s11661-024-07589-0}, pages = {4585 -- 4599}, year = {2024}, language = {en} } @inproceedings{KubaschinskiBaruthTetzlaffetal.2022, author = {Kubaschinski, Paul and Baruth, Albin and Tetzlaff, Ulrich and Altenbach, Holm and Waltz, Manuela}, title = {Untersuchungen zur Ermittlung der zyklischen Kennwerte von d{\"u}nnem Elektroblech im Rahmen der rechnerischen Lebensdauerabsch{\"a}tzung}, pages = {BF-2022-014}, booktitle = {Betriebsfestigkeit - Wissensmanagement und Methodenentwicklung entlang der Wertsch{\"o}pfungskette}, publisher = {DVM}, address = {Berlin}, doi = {https://doi.org/10.48447/BF-2022-014}, pages = {163 -- 178}, year = {2022}, language = {de} } @inproceedings{KeimTetzlaffElger2020, author = {Keim, Simon and Tetzlaff, Ulrich and Elger, Gordon}, title = {The influence of different-sized Ni micro- and nanopowders on the processing and microstructural properties of Sn-Ag-Cu-solder with low Ag content}, booktitle = {Proceedings: IEEE 70th Electronic Components and Technology Conference, ECTC 2020}, publisher = {IEEE}, address = {Piscataway}, isbn = {978-1-7281-6180-8}, issn = {2377-5726}, doi = {https://doi.org/10.1109/ECTC32862.2020.00312}, pages = {2005 -- 2012}, year = {2020}, language = {en} } @article{BhogarajuContiKotadiaetal.2020, author = {Bhogaraju, Sri Krishna and Conti, Fosca and Kotadia, Hiren R. and Keim, Simon and Tetzlaff, Ulrich and Elger, Gordon}, title = {Novel approach to copper sintering using surface enhanced brass micro flakes for microelectronics packaging}, volume = {2020}, pages = {156043}, journal = {Journal of Alloys and Compounds}, number = {844}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-4669}, doi = {https://doi.org/10.1016/j.jallcom.2020.156043}, year = {2020}, language = {en} } @article{MokhtariContiBhogarajuetal.2019, author = {Mokhtari, Omid and Conti, Fosca and Bhogaraju, Sri Krishna and Meier, Markus and Schweigart, Helmut and Tetzlaff, Ulrich and Elger, Gordon}, title = {Characterization of tin-oxides and tin-formate crystals obtained from SnAgCu solder alloy under formic acid vapor}, volume = {43}, journal = {New Journal of Chemistry}, number = {26}, publisher = {RSC}, address = {London}, issn = {1369-9261}, doi = {https://doi.org/10.1039/C9NJ02135C}, pages = {10227 -- 10231}, year = {2019}, language = {en} } @article{GottwaltKubaschinskiWaltzetal.2022, author = {Gottwalt, Albin and Kubaschinski, Paul and Waltz, Manuela and Glatzel, Uwe and Tetzlaff, Ulrich}, title = {An experimental setup for fatigue testing of thin electrical steel sheets}, volume = {2022}, pages = {106987}, journal = {International Journal of Fatigue}, number = {162}, publisher = {Elsevier}, address = {Oxford}, issn = {0142-1123}, doi = {https://doi.org/10.1016/j.ijfatigue.2022.106987}, year = {2022}, abstract = {In this study, the fatigue behavior of thin electrical steel sheets under cyclic loading is investigated. Results from strain-controlled and stress-controlled fatigue tests with different specimen geometries and different test setups are presented and compared with conventional testing methods. The results imply that conventional testing methods should be adjusted for testing thin electrical steel sheets because the fatigue life depends significantly on the test setup as well as the specimen geometry. Therefore, this study proposes an improved specimen geometry and test setup for stress- and strain-controlled fatigue tests of thin electrical steel sheets depending on the desired testing parameters.}, language = {en} } @article{ThambiSchiesslWaltzetal.2017, author = {Thambi, Joel Luther and Schiessl, Andreas and Waltz, Manuela and Lang, Klaus-Dieter and Tetzlaff, Ulrich}, title = {Modified Constitutive Creep Laws With Micromechanical Modeling of Pb-Free Solder Alloys}, volume = {139}, pages = {031002}, journal = {Journal of Electronic Packaging}, number = {3}, publisher = {The American Society of Mechanical Engineers}, address = {New York}, issn = {1528-9044}, doi = {https://doi.org/10.1115/1.4035850}, year = {2017}, language = {en} } @article{ThambiTetzlaffSchiessletal.2016, author = {Thambi, Joel Luther and Tetzlaff, Ulrich and Schiessl, Andreas and Lang, Klaus-Dieter and Waltz, Manuela}, title = {High cycle fatigue behaviour and generalized fatigue model development of lead-free solder alloy based on local stress approach}, journal = {Microelectronics Reliability}, number = {66}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0026-2714}, doi = {https://doi.org/10.1016/j.microrel.2016.10.004}, pages = {98 -- 105}, year = {2016}, language = {en} } @article{CorreadaSilvaVolpatoFredeletal.2019, author = {Corr{\^e}a da Silva, Cau{\^e} and Volpato, Guilherme and Fredel, M{\´a}rcio Celso and Tetzlaff, Ulrich}, title = {Low-pressure processing and microstructural evaluation of unidirectional carbon fiber-reinforced aluminum-nickel matrix composites}, volume = {2019}, journal = {Journal of Materials Processing Technology}, number = {269}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0924-0136}, doi = {https://doi.org/10.1016/j.jmatprotec.2019.01.032}, pages = {10 -- 15}, year = {2019}, language = {en} } @inproceedings{VolpatoFredelTetzlaff2019, author = {Volpato, Guilherme and Fredel, M{\´a}rcio Celso and Tetzlaff, Ulrich}, title = {Dry Sliding Wear and Fe Contamination of Investment-cast SiC Foam Reinforced Aluminum Matrix Composites}, booktitle = {EuroBrake 2019 Conference Proceedings}, publisher = {FISITA}, address = {Bishops Stortford}, isbn = {978-0-9572076-3-9}, year = {2019}, language = {en} } @article{LemosFredelPyczaketal.2019, author = {Lemos, Georges and Fredel, M{\´a}rcio Celso and Pyczak, Florian and Tetzlaff, Ulrich}, title = {Influence of distinct manufacturing processes on the microstructure of Ni-based metal matrix composites submitted to long thermal exposure}, volume = {2019}, journal = {Key Engineering Materials}, number = {809}, publisher = {Trans Tech Publications}, address = {Baech}, issn = {1662-9795}, doi = {https://doi.org/10.4028/www.scientific.net/KEM.809.79}, pages = {79 -- 86}, year = {2019}, language = {en} } @inproceedings{GuldenReinholdGramstatetal.2019, author = {Gulden, Florian and Reinhold, B. and Gramstat, Sebastian and Tetzlaff, Ulrich and H{\"o}ppel, Heinz Werner}, title = {Investigation of the run-in and corrosion behavior of a PEO-coated aluminum brake disc}, booktitle = {10th International Munich Chassis Symposium 2019: chassis.tech plus}, editor = {Pfeffer, Peter E.}, publisher = {Springer Vieweg}, address = {Wiesbaden}, isbn = {978-3-658-26435-2}, doi = {https://doi.org/10.1007/978-3-658-26435-2_43}, pages = {611 -- 631}, year = {2019}, language = {en} } @inproceedings{GuldenStichGramstatetal.2018, author = {Gulden, Florian and Stich, Anton and Gramstat, Sebastian and H{\"o}ppel, Heinz Werner and Tetzlaff, Ulrich}, title = {Investigations of the third body using pin-on-disc and brake dynamometer on all-MMC brake rotors}, booktitle = {EuroBrake 2018 Conference Proceedings}, publisher = {FISITA}, address = {Bishops Stortford}, isbn = {978-1-5108-7963-8}, pages = {401 -- 407}, year = {2018}, language = {en} } @article{BenedetDutraTetzlaffVieiradaCunhaetal.2022, author = {Benedet Dutra, Gabriel and Tetzlaff, Ulrich and Vieira da Cunha, Tiago and dos Santos, Carlos Eduardo and Lemos, Georges}, title = {Microstructural Characterization of an ERNiCrMo-3 and Grey Cast Iron Interface Obtained via TIG Welding}, volume = {53}, journal = {Metallurgical and Materials Transactions B}, number = {4}, publisher = {Springer Nature}, address = {Cham}, issn = {1073-5615}, doi = {https://doi.org/10.1007/s11663-022-02549-8}, pages = {2534 -- 2546}, year = {2022}, language = {en} } @article{KubaschinskiGottwaltTetzlaffetal.2023, author = {Kubaschinski, Paul and Gottwalt, Albin and Tetzlaff, Ulrich and Altenbach, Holm and Waltz, Manuela}, title = {Modelling and simulation of the hardness profile and its effect on the stress-strain behaviour of punched electrical steel sheets}, volume = {54}, journal = {Materials Science \& Engineering Technology}, number = {4}, publisher = {Wiley}, address = {Weinheim}, issn = {0933-5137}, doi = {https://doi.org/10.1002/mawe.202200283}, pages = {512 -- 526}, year = {2023}, abstract = {The shear cutting of electrical steel sheets has a significant influence on the magnetic and mechanical material properties. Due to plastic deformation and strain hardening in the area of the punched edge, the electrical steel sheets exhibit a characteristic hardness profile. This study deals with the modelling of the resulting hardness profile by means of finite-element simulations. Elastic-plastic material properties are obtained from spherical nanoindentation testing as a function of the local hardness. In particular, representative stress-strain values are determined by applying Tabor's concept of indentation stress-strain curves. The choice of the appropriate stress- and strain-constraint factors is discussed with respect to the nanoindentation test setup used. Following this, the representative stress-strain values are analytically described to determine true stress-strain curves for the local assignment of different material models depending on the hardness. The implementation of the modelling approach in a finite-element simulation is presented for a punched electrical steel sheet specimen under monotonic loading. The simulation results are basically in good agreement with experimental data and confirm the expected influence on the mechanical material behaviour due to the shear cutting process.}, language = {en} } @article{HandwerkerKesslerMarzbanietal.2021, author = {Handwerker, Michael and Kessler, J{\"o}rg and Marzbani, Hormoz and Tetzlaff, Ulrich}, title = {Annealing of chopped and continuous fibre reinforced polyamide 6 produced by fused filament fabrication}, volume = {2021}, pages = {109119}, journal = {Composites Part B: Engineering}, number = {223}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-1069}, doi = {https://doi.org/10.1016/j.compositesb.2021.109119}, year = {2021}, language = {en} } @article{ThambiTetzlaffSchiessletal.2020, author = {Thambi, Joel Luther and Tetzlaff, Ulrich and Schiessl, Andreas and Lang, Klaus-Dieter and Waltz, Manuela}, title = {Evaluation of the relationship between stress and lifetime of Pb-free solder joints subjected to vibration load using a generalized local stress approach}, volume = {2020}, pages = {113560}, journal = {Microelectronics Reliability}, number = {106}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0026-2714}, doi = {https://doi.org/10.1016/j.microrel.2019.113560}, year = {2020}, language = {en} } @article{TetzlaffGerberAmelangetal.2019, author = {Tetzlaff, Ulrich and Gerber, Alexander and Amelang, Rudolf and Lemos, Georges}, title = {Investigation of the Creep Resistance of a Spray-Compacted Si-Particle Reinforced Al-Based MMC (Dispal® S270)}, volume = {2019}, journal = {Key Engineering Materials}, number = {809}, publisher = {Trans Tech Publications}, address = {Baech}, issn = {1662-9795}, doi = {https://doi.org/10.4028/www.scientific.net/KEM.809.87}, pages = {87 -- 93}, year = {2019}, language = {en} } @article{KubaschinskiGottwaltTetzlaffetal.2022, author = {Kubaschinski, Paul and Gottwalt, Albin and Tetzlaff, Ulrich and Altenbach, Holm and Waltz, Manuela}, title = {Calibration of a combined isotropic-kinematic hardening material model for the simulation of thin electrical steel sheets subjected to cyclic loading}, volume = {53}, journal = {Materials Science \& Engineering Technology}, number = {4}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-4052}, doi = {https://doi.org/10.1002/mawe.202100341}, pages = {422 -- 439}, year = {2022}, abstract = {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.}, language = {en} } @article{KiehlScheidGrafetal.2023, author = {Kiehl, Maximilian and Scheid, Adriano and Graf, Karin and Ernst, Benedikt and Tetzlaff, Ulrich}, title = {Coaxial laser cladding of cobalt-base alloy Stellite™ 6 on gray cast iron/investigations on friction, wear versus commercial brake pad, and corrosion characteristics}, volume = {237}, journal = {Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering}, number = {14}, publisher = {Sage}, address = {London}, issn = {2041-2991}, doi = {https://doi.org/10.1177/09544070221145512}, pages = {3285 -- 3303}, year = {2023}, language = {en} } @article{ErnstKeimTetzlaff2022, author = {Ernst, Benedikt and Keim, Simon and Tetzlaff, Ulrich}, title = {On the anisotropic indentation modulus and anisotropic creep behavior of β-Sn characterized by nanoindentation methods}, volume = {2022}, pages = {143392}, journal = {Materials Science and Engineering: A}, number = {848}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-4936}, doi = {https://doi.org/10.1016/j.msea.2022.143392}, year = {2022}, language = {en} } @article{HandwerkerKesslerMarzbanietal.2022, author = {Handwerker, Michael and Kessler, J{\"o}rg and Marzbani, Hormoz and Tetzlaff, Ulrich}, title = {Pressure and heat treatment of continuous fibre reinforced thermoplastics produced by fused filament fabrication}, volume = {8}, journal = {Progress in Additive Manufacturing}, number = {2}, publisher = {Springer}, address = {Cham}, issn = {2363-9520}, doi = {https://doi.org/10.1007/s40964-022-00315-5}, pages = {99 -- 116}, year = {2022}, abstract = {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.}, language = {en} } @article{LemosFredelPyczaketal.2022, author = {Lemos, Georges and Fredel, M{\´a}rcio Celso and Pyczak, Florian and Tetzlaff, Ulrich}, title = {Creep resistance improvement of a polycrystalline Ni-based superalloy via TiC particles reinforcement}, volume = {2022}, pages = {143821}, journal = {Materials Science and Engineering: A}, number = {854}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-4936}, doi = {https://doi.org/10.1016/j.msea.2022.143821}, year = {2022}, language = {en} } @article{VolpatoTetzlaffFredel2022, author = {Volpato, Guilherme and Tetzlaff, Ulrich and Fredel, M{\´a}rcio Celso}, title = {A comprehensive literature review on laser powder bed fusion of Inconel superalloys}, volume = {2022}, pages = {102871}, journal = {Additive Manufacturing}, number = {55}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2214-7810}, doi = {https://doi.org/10.1016/j.addma.2022.102871}, year = {2022}, language = {en} } @article{ErnstKubaschinskiSchiessletal.2024, author = {Ernst, Benedikt and Kubaschinski, Paul and Schiessl, Andreas and Waltz, Manuela and H{\"o}ppel, Heinz Werner and Tetzlaff, Ulrich}, title = {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}, volume = {2024}, pages = {147354}, journal = {Materials Science and Engineering: A}, number = {916}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1873-4936}, doi = {https://doi.org/10.1016/j.msea.2024.147354}, year = {2024}, abstract = {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.}, language = {en} } @article{GottwaltKubaschinskiWaltzetal.2023, author = {Gottwalt, Albin and Kubaschinski, Paul and Waltz, Manuela and Tetzlaff, Ulrich}, title = {Influence of the cutting method on the fatigue life and crack initiation of non-oriented electrical steel sheets}, volume = {2024}, pages = {108073}, journal = {International Journal of Fatigue}, number = {180}, publisher = {Elsevier}, address = {Oxford}, issn = {1879-3452}, doi = {https://doi.org/10.1016/j.ijfatigue.2023.108073}, year = {2023}, abstract = {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.}, language = {en} } @article{GottwaltKubaschinskiWaltzetal.2023, author = {Gottwalt, Albin and Kubaschinski, Paul and Waltz, Manuela and V{\"o}lkl, Rainer and Glatzel, Uwe and Tetzlaff, Ulrich}, title = {Cyclic deformation behavior of non-oriented electrical steel sheets}, volume = {2023}, pages = {145684}, journal = {Materials Science and Engineering: A}, number = {886}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0921-5093}, doi = {https://doi.org/10.1016/j.msea.2023.145684}, year = {2023}, language = {en} } @article{ViewegerDielSchweigeretal.2024, author = {Vieweger, Daniel and Diel, Sergej and Schweiger, Hans-Georg and Tetzlaff, Ulrich}, title = {Mechanical Properties of Raw Filaments and Printed Specimens: Effects of Fiber Reinforcements and Process Parameters}, volume = {16}, pages = {1576}, journal = {Polymers}, number = {11}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, doi = {https://doi.org/10.3390/polym16111576}, year = {2024}, abstract = {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.}, language = {en} } @article{GottwaltKubaschinskiWaltzetal.2024, author = {Gottwalt, Albin and Kubaschinski, Paul and Waltz, Manuela and Tetzlaff, Ulrich}, title = {Influence of Subsequent Heat Treatment on Fatigue Behavior of Shear-Cut Electrical Steel Sheets}, volume = {3}, journal = {Alloys}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2674-063X}, doi = {https://doi.org/10.3390/alloys3040017}, pages = {281 -- 294}, year = {2024}, abstract = {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.}, language = {en} } @article{deSouzaPintoPereiraGutjahrPereiraetal.2023, author = {de Souza Pinto Pereira, Adriano and Gutjahr, Jhonattan and Pereira, Milton and Tetzlaff, Ulrich and Fredel, M{\´a}rcio Celso}, title = {Processability of thin-powdered Inconel X750 and TiC metal matrix composite by laser-directed energy deposition}, volume = {35}, pages = {042040}, journal = {Journal of Laser Applications}, number = {4}, publisher = {LIA}, address = {Orlando}, issn = {1042-346X}, doi = {https://doi.org/10.2351/7.0001134}, year = {2023}, language = {en} } @inproceedings{MohdKreinerSchmidetal.2024, author = {Mohd, Zubair Akhtar and Kreiner, Christian and Schmid, Maximilian and Zippelius, Andreas and Tetzlaff, Ulrich and Elger, Gordon}, title = {Fully Connected Neural Network (FCNN) Based Validation Framework for FEA Post Processing to Improve SAC Solder Reliability Analysis}, booktitle = {2024 IEEE 10th Electronics System-Integration Technology Conference (ESTC), Proceedings}, publisher = {IEEE}, address = {Piscataway}, isbn = {979-8-3503-9036-0}, doi = {https://doi.org/10.1109/ESTC60143.2024.10712023}, year = {2024}, language = {en} } @article{VolpatodeSouzaPintoPereiraNeumeieretal.2025, author = {Volpato, Guilherme and de Souza Pinto Pereira, Adriano and Neumeier, Steffen and Hotza, Dachamir and G{\"o}ken, Mathias and Tetzlaff, Ulrich and Fredel, M{\´a}rcio Celso}, title = {Influence of a Standard Heat Treatment on the Microstructure and Properties of Inconel X-750 Produced by Laser Powder Bed Fusion}, volume = {27}, pages = {2500306}, journal = {Advanced Engineering Materials}, number = {24}, publisher = {Wiley}, address = {Weinheim}, issn = {1527-2648}, doi = {https://doi.org/10.1002/adem.202500306}, year = {2025}, abstract = {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.}, language = {en} } @article{GuldenGramstatStichetal.2018, author = {Gulden, Florian and Gramstat, Sebastian and Stich, Anton and Hoppel, Heinz Werner and Tetzlaff, Ulrich}, title = {Properties and Limitation of an Oxide Coated Aluminum Brake Rotor}, pages = {2018-01-1877}, journal = {SAE Technical Paper}, publisher = {SAE}, address = {Warrendale}, issn = {0148-7191}, doi = {https://doi.org/10.4271/2018-01-1877}, year = {2018}, language = {en} }