@article{33338, author = {{Hein, Maxwell}}, journal = {{Crystals}}, publisher = {{MDPI}}, title = {{{Influence of Physical Vapor Deposition on High-Cycle Fatigue Performance of Additively Manufactured Ti-6Al-7Nb Alloy}}}, doi = {{10.3390/cryst12091190}}, year = {{2022}}, } @article{33340, author = {{Hein, Maxwell and Lopes Dias, Nelson Filipe and Pramanik, Sudipta and Stangier, Dominic and Hoyer, Kay-Peter and Tillmann, Wolfgang and Schaper, Mirko}}, journal = {{Materials}}, title = {{{Heat Treatments of Metastable β Titanium Alloy Ti-24Nb-4Zr-8Sn Processed by Laser Powder Bed Fusion}}}, year = {{2022}}, } @inproceedings{25047, author = {{Křivská, B and Šlapáková, M and Králík, R and Bajtošová, L and Cieslar, M and Grydin, Olexandr and Stolbchenko, M and Schaper, Mirko}}, booktitle = {{IOP Conference Series: Materials Science and Engineering}}, issn = {{1757-899X}}, title = {{{Resistivity and Formation of Intermetallic Layer in Aluminum-Steel Clad Strip}}}, doi = {{10.1088/1757-899x/1178/1/012035}}, volume = {{1178}}, year = {{2021}}, } @article{28017, abstract = {{Processing aluminum alloys employing powder bed fusion of metals (PBF-LB/M) is becoming more attractive for the industry, especially if lightweight applications are needed. Unfortunately, high-strength aluminum alloys such as AA7075 are prone to hot cracking during PBF-LB/M, as well as welding. Both a large solidification range promoted by the alloying elements zinc and copper and a high thermal gradient accompanied with the manufacturing process conditions lead to or favor hot cracking. In the present study, a simple method for modifying the powder surface with titanium carbide nanoparticles (NPs) as a nucleating agent is aimed. The effect on the microstructure with different amounts of the nucleating agent is shown. For the aluminum alloy 7075 with 2.5 ma% titanium carbide nanoparticles, manufactured via PBF-LB/M, crack-free samples with a refined microstructure having no discernible melt pool boundaries and columnar grains are observed. After using a two-step ageing heat treatment, ultimate tensile strengths up to 465 MPa and an 8.9% elongation at break are achieved. Furthermore, it is demonstrated that not all nanoparticles used remain in the melt pool during PBF-LB/M.}}, author = {{Heiland, Steffen and Milkereit, Benjamin and Hoyer, Kay-Peter and Zhuravlev, Evgeny and Keßler, Olaf and Schaper, Mirko}}, journal = {{Materials}}, keywords = {{grain refinement, crack reduction, laser beam melting, aluminum alloy, titanium carbide, nanoparticle, PBF-LB/M}}, title = {{{Requirements for Processing High-Strength AlZnMgCu Alloys with PBF-LB/M to Achieve Crack-Free and Dense Parts}}}, doi = {{https://doi.org/10.3390/ma14237190}}, year = {{2021}}, } @inproceedings{28440, author = {{Triebus, Marcel and Reitz, Alexander and Grydin, Olexandr and Grenz, Julian and Schneidt, Andreas and Erhardt, Rüdiger and Tröster, Thomas and Schaper, Mirko}}, booktitle = {{13th European LS-DYNA Conference 2021}}, location = {{Ulm}}, title = {{{Forming Simulation of Tailored Press Hardened Parts}}}, year = {{2021}}, } @inproceedings{24426, author = {{Urbanek, Stefan and Pauline, Frey and Magerkohl, Sebastian and Zimmer, Detmar and Tasche, Lennart and Schaper, Mirko and Ponick, Bernd}}, keywords = {{Elektromotor, Elektromaschine, Additive Fertigung, AF, AM, Additive Manufacturing, DMRC, KAt}}, location = {{Connecticut, USA}}, title = {{{Design and Experimental Investigation of an Additively Manufactured PMSM Rotor}}}, doi = {{10.1109/IEMDC47953.2021.9449566}}, year = {{2021}}, } @article{24589, abstract = {{Additive manufacturing, e.g. by laser powder bed fusion (LPBF), is very attractive for lightweight constructions, as complex and stress-optimised structures integrating multiple functions can be produced within one process. Unfortunately, high strength AlZnMgCu alloys tend to hot cracking during LPBF and thus have not so far been applicable. In this work the melting and solidification behaviour of AlZnMgCu alloy powder variants with particle surface inoculation was analysed by Differential Fast Scanning Calorimetry. The aim is to establish a method that makes it possible to assess powder modifications in terms of their suitability for LPBF on a laboratory scale requiring only small amounts of powder. Therefore, solidification undercooling is evaluated at cooling rates relevant for LPBF. A method for the temperature correction and normalisation of the DFSC results is proposed. Two ways of powder modification were tested for the powder particles surface inoculation by titanium carbide (TiC) nanoparticles: via wet-chemical deposition and via mechanical mixing. A low undercooling from DFSC correlates with a low number of cracks of LPBF-manufactured cubes. It appears that a reduced undercooling combined with reduced solidification onset scatter indicates the possibility of crack-free LPBF of alloys that otherwise tend to hot cracking.}}, author = {{Zhuravlev, Evgeny and Milkereit, Benjamin and Yang, Bin and Heiland, Steffen and Vieth, Pascal and Voigt, Markus and Schaper, Mirko and Grundmeier, Guido and Schick, Christoph and Kessler, Olaf}}, issn = {{0264-1275}}, journal = {{Materials & Design}}, keywords = {{Aluminium alloy 7075, Differential fast scanning calorimetry, Solidification, Undercooling, Additive manufacturing}}, title = {{{Assessment of AlZnMgCu alloy powder modification for crack-free laser powder bed fusion by differential fast scanning calorimetry}}}, doi = {{10.1016/j.matdes.2021.109677}}, year = {{2021}}, } @article{26191, author = {{Voswinkel, Dietrich and Sapli, Hüseyin and Kloidt, Dennis and Heggemann, Thomas and Homberg, Werner and Grydin, Olexandr and Schaper, Mirko}}, issn = {{1757-8981}}, journal = {{IOP Conference Series: Materials Science and Engineering}}, title = {{{Improving the Accuracy of Deep Drawn Fiber-Metal Laminate Parts by Preliminary Surface Treatment}}}, doi = {{10.1088/1757-899x/1190/1/012028}}, year = {{2021}}, } @phdthesis{26900, abstract = {{Mit Hilfe der additiven Fertigung, insbesondere dem pulverbettbasierten selektiven Laserstrahl-schmelzen (LBM), können hochkomplexe Strukturen endkonturnah hergestellt werden. Die große Designfreiheit ermöglicht, zelluläre Leichtbaustrukturen zu erzeugen, deren mikrostrukturellen und mechanischen Eigenschaften direkt vom generativen Fertigungsverfahren abhängen. Insbesondere im Bereich des Leichtbaus bieten zelluläre Strukturen neue Ansätze zur Verminderung des Energieverbrauchs. Um dieses Potential vollständig ausschöpfen zu können, müssen die Effekte, die zum Versagen der Bauteile mit integrierten Gitterstrukturen führen, quantitativ beschrieben und verstanden werden. Dies ist Voraussetzung für eine sichere Auslegung. Dazu werden im Rahmen der vorliegenden Arbeit die charakteristischen Eigenschaften dieser Strukturen sowie die Einflussgrößen im Aufbauprozess näher beleuchtet. Im Rahmen dieser Dissertation werden numerische und experimentelle Untersuchungen von zwei unterschiedlichen Gitterstrukturtypen aus den Werkstoffen 316L und TiAl6V4 vorgestellt. Beide Werkstoffe werden unter monotoner, einachsiger Belastung getestet. Die parallel dazu durchgeführte digitale Bildkorrelation (DIC) ermöglicht gleichzeitig die detaillierte Analyse der lokalen Dehnungsverteilung während der Verformung. Mikrostrukturelle Eigenschaften und die resultierenden Gittercharakteristika werden mit Hilfe von rasterelektronenmikroskopischen Analysemethoden untersucht. Zudem erfolgt die Entwicklung eines Finite-Elemente- Modells, mit der Anforderung eines möglichst geringen Rechenaufwandes. Ein abschließender Vergleich der realen Dehnungsverteilung mit der FE- Analyse verifiziert das Modell.}}, author = {{Sieger, Alexander}}, isbn = {{ 978-3-8440-7924-1}}, keywords = {{Additive Fertigung, TiAl6V4, 316L, Gitterstrukturen, L-PBF}}, pages = {{136}}, title = {{{Mikrostrukturausprägung additiv gefertigter Gitterstrukturen}}}, volume = {{23}}, year = {{2021}}, } @inproceedings{29812, abstract = {{Aluminum-steel clad composites are used as structural elements in car bodies and chases as well as in the chemical industry due to a combination of high strength of steel, low density of Al and high corrosion resistance of both materials. An important parameter influencing mechanical properties of the composite is the microstructure of the bonding region between Al and steel layer. During manufacturing of the final product, clad sheets can be subjected to elevated temperatures which enhance diffusion between the metals. As a result, a brittle intermetallic phase, deteriorating the bond strength between steel and aluminum, forms at the interface. This paper focuses on study of the interfacial microstructure in a twin-roll cast Al-steel clad strip and its evolution during in-situ annealing in transmission electron microscope. Due to isochronal annealing above 500 °C, Al5Fe2 phase forms at the interface. Nucleation centers formed at the beginning of heating experiment expand and form continuous layer. The kinetics of the growth follows the parabolic law typical for diffusion-controlled phase transformations.}}, author = {{Křivská, Barbora and Šlapáková, Michaela and Minárik, Peter and Fekete, Klaudia and Králík, Rostislav and Stolbchenko, Mykhailo and Schaper, Mirko and Grydin, Olexandr}}, booktitle = {{APPLIED PHYSICS OF CONDENSED MATTER (APCOM 2021)}}, issn = {{0094-243X}}, location = {{Online}}, publisher = {{AIP Publishing}}, title = {{{In-situ TEM observation of intermetallic phase growth in Al-steel clad sheet}}}, doi = {{10.1063/5.0067491}}, year = {{2021}}, } @article{24535, abstract = {{Implementing the concept of mixed construction in modern automotive engineering requires the joining of sheet metal or extruded profiles with cast components made from different materials. As weight reduction is desired, these cast components are usually made from high-strength aluminium alloys of the Al-Si (Mn, Mg) system, which have limited weldability. The mechanical joinability of the cast components depends on their ductility, which is influenced by the microstructure. High-strength cast aluminium alloys have relatively low ductility, which leads to cracking of the joints. This limits the range of applications for cast aluminium alloys. In this study, an aluminium alloy of the Al-Si system AlSi9 is used to investigate relationships between solidification conditions during the sand casting process, microstructure, mechanical properties, and joinability. The demonstrator is a stepped plate with a minimum thickness of 2.0 mm and a maximum thickness of 4.0 mm, whereas the thickness difference between neighbour steps amounts to 0.5 mm. During casting trials, the solidification rates for different plate steps were measured. The microscopic investigations reveal a correlation between solidification rates and microstructure parameters such as secondary dendrite arm spacing. Furthermore, mechanical properties and the mechanical joinability are investigated.}}, author = {{Neuser, Moritz and Grydin, Olexandr and Andreiev, Anatolii and Schaper, Mirko}}, issn = {{2075-4701}}, journal = {{Metals}}, title = {{{Effect of Solidification Rates at Sand Casting on the Mechanical Joinability of a Cast Aluminium Alloy}}}, doi = {{10.3390/met11081304}}, year = {{2021}}, } @article{24537, author = {{Neuser, Moritz and Kappe, Fabian and Busch, M and Grydin, Olexandr and Bobbert, Mathias and Schaper, Mirko and Meschut, Gerson and Hausotte, T}}, issn = {{1757-8981}}, journal = {{IOP Conference Series: Materials Science and Engineering}}, title = {{{Joining suitability of cast aluminium for self-piercing riveting}}}, doi = {{10.1088/1757-899x/1157/1/012005}}, year = {{2021}}, } @phdthesis{42013, author = {{Stolbchenko, Mykhailo }}, isbn = {{978-3-8440-7971-5}}, publisher = {{Shaker Verlag}}, title = {{{Zwei-Rollen-Gießwalzen und thermomechanische Behandlung von dünnen Bändern aus der Aluminiumlegierung EN AW-6082}}}, year = {{2021}}, } @inproceedings{24006, author = {{Weiß, Deborah and Schramm, Britta and Neuser, Moritz and Grydin, Olexandr and Kullmer, Gunter}}, location = {{Bremen}}, pages = {{231--240}}, title = {{{Experimentelle bruchmechanische Untersuchung eines clinchgeeigneten Bleches aus HCT590X mithilfe einer neuen Probengeometrie}}}, doi = {{10.48447/BR-2021-025}}, volume = {{DVM-Bericht 253}}, year = {{2021}}, } @article{41511, author = {{Hein, Maxwell and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{0933-5137}}, journal = {{Materialwissenschaft und Werkstofftechnik}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, number = {{7}}, pages = {{703--716}}, publisher = {{Wiley}}, title = {{{Additively processed TiAl6Nb7 alloy for biomedical applications}}}, doi = {{10.1002/mawe.202000288}}, volume = {{52}}, year = {{2021}}, } @article{41507, abstract = {{ Purpose The currently existing restrictions regarding the deployment of additively manufactured components because of poor surface roughness, porosity and residual stresses as well as their influence on the low-cycle fatigue (LCF) strength are addressed in this paper. Design/methodology/approach This study aims to evaluating the effect of different pre- and post-treatments on the LCF strength of additively manufactured 316L parts. Therefore, 316L specimens manufactured by laser powder bed fusion were examined in their as-built state as well as after grinding, or coating with regard to the surface roughness, residual stresses and LCF strength. To differentiate between topographical effects and residual stress-related phenomena, stress-relieved 316L specimens served as a reference throughout the investigations. To enable an alumina coating of the 316L components, atmospheric plasma spraying was used, and the near-surface residual stresses and the surface roughness are measured and investigated. Findings The results have shown that the applied pre- and post-treatments such as stress-relief heat treatment, grinding and alumina coating have each led to an increase in LCF strength of the 316L specimens. In contrast, the non-heat-treated specimens predominantly exhibited coating delamination. Originality/value To the best of the authors’ knowledge, this is the first study of the correlation between the LCF behavior of additively manufactured uncoated 316L specimens in comparison with additively manufactured 316L specimens with an alumina coating. }}, author = {{Garthe, Kai-Uwe and Hoyer, Kay-Peter and Hagen, Leif and Tillmann, Wolfgang and Schaper, Mirko}}, issn = {{1355-2546}}, journal = {{Rapid Prototyping Journal}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering}}, number = {{5}}, pages = {{833--840}}, publisher = {{Emerald}}, title = {{{Correlation between pre- and post-treatments of additively manufactured 316L parts and the resulting low cycle fatigue behavior}}}, doi = {{10.1108/rpj-01-2021-0017}}, volume = {{28}}, year = {{2021}}, } @article{41506, abstract = {{Processing aluminum alloys employing powder bed fusion of metals (PBF-LB/M) is becoming more attractive for the industry, especially if lightweight applications are needed. Unfortunately, high-strength aluminum alloys such as AA7075 are prone to hot cracking during PBF-LB/M, as well as welding. Both a large solidification range promoted by the alloying elements zinc and copper and a high thermal gradient accompanied with the manufacturing process conditions lead to or favor hot cracking. In the present study, a simple method for modifying the powder surface with titanium carbide nanoparticles (NPs) as a nucleating agent is aimed. The effect on the microstructure with different amounts of the nucleating agent is shown. For the aluminum alloy 7075 with 2.5 ma% titanium carbide nanoparticles, manufactured via PBF-LB/M, crack-free samples with a refined microstructure having no discernible melt pool boundaries and columnar grains are observed. After using a two-step ageing heat treatment, ultimate tensile strengths up to 465 MPa and an 8.9% elongation at break are achieved. Furthermore, it is demonstrated that not all nanoparticles used remain in the melt pool during PBF-LB/M.}}, author = {{Heiland, Steffen and Milkereit, Benjamin and Hoyer, Kay-Peter and Zhuravlev, Evgeny and Kessler, Olaf and Schaper, Mirko}}, issn = {{1996-1944}}, journal = {{Materials}}, keywords = {{General Materials Science}}, number = {{23}}, publisher = {{MDPI AG}}, title = {{{Requirements for Processing High-Strength AlZnMgCu Alloys with PBF-LB/M to Achieve Crack-Free and Dense Parts}}}, doi = {{10.3390/ma14237190}}, volume = {{14}}, year = {{2021}}, } @article{24790, abstract = {{Implants often overtake body function just for a certain time and remain as an unnecessary foreign body or have to be removed. Thus, resorbable implants are highly beneficial to reduce patient burden. Besides established materials, Iron-(Fe)-based alloys are in focus due to superior mechanical properties and good biocompatibility. However, their degradation rate needs to be increased. Phases with high electrochemical potential could promote the dissolution of residual material based on the galvanic coupling. Silver (Ag) is promising due to its high electrochemical potential (+0.8 V vs. SHE), immiscibility with Fe, biocompatibility, and anti-bacterial properties. But to prevent adverse consequences the Ag-particles, remaining after dissolution of the matrix, need to dissolve. Thus, a bioresorbable Ag-alloy is required. Regarding the electrochemical potential and degradation behavior of binary alloys, Cerium (Ce) and Lanthanum (La) are well-suited considering their biocompatibility and antibacterial behavior. Accordingly, this research addresses AgCe and AgCeLa alloys as additives for Fe-based materials with adapted degradation behavior. Furthermore, degradable Ag-alloys combined with inert implant materials could enable the controlled release of antibacterial active Ag-ions.}}, author = {{Krüger, Jan Tobias and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{0167-577X}}, journal = {{Materials Letters}}, title = {{{Bioresorbable AgCe and AgCeLa alloys for adapted Fe-based implants}}}, doi = {{10.1016/j.matlet.2021.130890}}, volume = {{306}}, year = {{2021}}, } @article{41516, author = {{Tillmann, Wolfgang and Lopes Dias, Nelson Filipe and Franke, Carlo and Kokalj, David and Stangier, Dominic and Filor, Viviane and Mateus-Vargas, Rafael Hernán and Oltmanns, Hilke and Kietzmann, Manfred and Meißner, Jessica and Hein, Maxwell and Pramanik, Sudipta and Hoyer, Kay-Peter and Schaper, Mirko and Nienhaus, Alexander and Thomann, Carl Arne and Debus, Jörg}}, issn = {{0257-8972}}, journal = {{Surface and Coatings Technology}}, keywords = {{Materials Chemistry, Surfaces, Coatings and Films, Surfaces and Interfaces, Condensed Matter Physics, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Tribo-mechanical properties and biocompatibility of Ag-containing amorphous carbon films deposited onto Ti6Al4V}}}, doi = {{10.1016/j.surfcoat.2021.127384}}, volume = {{421}}, year = {{2021}}, } @article{41512, author = {{Andreiev, Anatolii and Hoyer, Kay-Peter and Dula, Dimitri and Hengsbach, Florian and Grydin, Olexandr and Frolov, Yaroslav and Schaper, Mirko}}, issn = {{0921-5093}}, journal = {{Materials Science and Engineering: A}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, publisher = {{Elsevier BV}}, title = {{{Laser beam melting of functionally graded materials with application-adapted tailoring of magnetic and mechanical performance}}}, doi = {{10.1016/j.msea.2021.141662}}, volume = {{822}}, year = {{2021}}, }