@article{59872,
  abstract     = {{Lightweight design is a driving concept in modern automotive engineering to minimize resource consumption over a vehicle's lifecycle through multi-material design, which relies on the use of joining techniques in car body fabrication. Multi-material design and the increasing trend towards producing large structural components using the megacasting process pose considerable challenges, particularly in the mechanical joining of aluminium-silicon (AlSi) castings. These castings typically exhibit low ductility and are prone to cracking when mechanically joined. Based on the excellent castability of hypoeutectic AlSi alloys, these are applied in sand casting and die casting as well as in megacasting. With a silicon content between 7 wt% and 12 wt%, these AlSi-alloys have a plate-like silicon phase that initiates cracks during mechanical joining. To enhance the joinability of castings, the research hypothesis is that improved solidification conditions enable a significant modification in the microstructure and therefore, increase the mechanical properties. During the manufacture of the castings using the sand casting process, the solidification conditions within the structural elements are varied to modify the microstructure to obtain castings with graded microstructure. The castings are evaluated using mechanical, microstructural and joining testing methods and finally, a microstructure-joinability correlation is established.}},
  author       = {{Neuser, Moritz and Schlichter, Malte Christian and Hoyer, Kay-Peter and Bobbert, Mathias and Meschut, Gerson and Schaper, Mirko}},
  journal      = {{44th Conference of the International Deep Drawing Research Group (IDDRG 2025)}},
  keywords     = {{Joining, Casting, Self-pierce riveting, Aluminium casting alloy}},
  location     = {{Lissabon (Portugal)}},
  title        = {{{Mechanical joinability of microstructurally graded structural components manufactured from hypoeutectic aluminium casting alloys}}},
  doi          = {{10.1051/matecconf/202540801081}},
  volume       = {{408}},
  year         = {{2025}},
}

@inproceedings{36335,
  abstract     = {{Transformation of Fe- and Cu-rich primary phase particles was studied in an Al-Li-based alloy prepared by twin-roll casting. Thin foils for combined STEM and SEM experiments were prepared by electrolytic twin-jet polishing. They were in-situ heated in a TEM heating stage and observed at 200 kV in the JEOL JEM 2200FS electron microscope equipped with STEM HAADF and BF detectors and SEM BSE and SE detectors working both in composition and topographic modes. The resulting structures were combined with EDS mapping performed directly in the heating holder. Dissolution and transformation of Cu- and Fe-rich particles occur above 500 °C. EDS maps acquired on the foil cooled down to room temperature show that Cu and Fe are both still present in newly formed particles, most likely indicating the presence of the Al7Cu2Fe phase.}},
  author       = {{CIESLAR, Miroslav and KŘIVSKÁ, Barbora and KRÁLÍK, Rostislav and BAJTOŠOVÁ, Lucia and Grydin, Olexandr and STOLBCHENKO, Mykhailo and Schaper, Mirko}},
  booktitle    = {{METAL 2022 Conference Proeedings}},
  issn         = {{2694-9296}},
  keywords     = {{Al-Li-based alloy, in-situ TEM, homogenization, phase transformation}},
  location     = {{Brno}},
  publisher    = {{TANGER Ltd.}},
  title        = {{{HOMOGENIZATION OF TWIN-ROLL CAST Al-Li-BASED ALLOY STUDIED BY IN-SITU ELECTRON MICROSCOPY}}},
  doi          = {{10.37904/metal.2022.4438}},
  year         = {{2022}},
}

@inproceedings{36339,
  abstract     = {{Al-Li-based alloys are an attractive material for aircraft and aerospace applications. Preparation of these alloys by twin-roll casting (TRC), which combines rapid metal solidification and subsequent plastic reduction in a single processing step, could improve the properties of the alloys compared to materials prepared by conventional direct-chill casting. A commonly used approach for identifying primary phases is a chemical analysis by energy dispersive spectroscopy (EDS). More accurate results can be achieved by combining the method with diffraction analysis. This process can be considerably simplified in microscopes equipped with automated crystal orientation and phase mapping (ACOM-TEM). Al-Cu-Li-Mg-Zr alloy was prepared by twin-roll casting. A combination of TEM and STEM images with chemical analysis by EDS and ACOM-TEM was used to obtain complex information about phases of boundary primary particles. The efficiency of the individual methods for the phase identification in TRC Al-Li-based alloys is discussed.}},
  author       = {{BAJTOŠOVÁ, Lucia and Grydin, Olexandr and STOLBCHENKO, Mykhailo and Schaper, Mirko and KŘIVSKÁ, Barbora and KRÁLÍK, Rostislav and ŠLAPÁKOVÁ, Michaela and CIESLAR, Miroslav}},
  booktitle    = {{METAL 2022 Conference Proeedings}},
  issn         = {{2694-9296}},
  keywords     = {{Al-Cu-Li-M-Zr-Fe alloy, twin-roll casting, phase identification, ACOM-TEM}},
  location     = {{Brno}},
  publisher    = {{TANGER Ltd.}},
  title        = {{{Phase identification in twin-roll cast Al-Li alloys}}},
  doi          = {{10.37904/metal.2022.4437}},
  year         = {{2022}},
}

@article{29196,
  abstract     = {{In biomedical engineering, laser powder bed fusion is an advanced manufacturing technology, which enables, for example, the production of patient-customized implants with complex geometries. Ti-6Al-7Nb shows promising improvements, especially regarding biocompatibility, compared with other titanium alloys. The biocompatible features are investigated employing cytocompatibility and antibacterial examinations on Al2O3-blasted and untreated surfaces. The mechanical properties of additively manufactured Ti-6Al-7Nb are evaluated in as-built and heat-treated conditions. Recrystallization annealing (925 °C for 4 h), β annealing (1050 °C for 2 h), as well as stress relieving (600 °C for 4 h) are applied. For microstructural investigation, scanning and transmission electron microscopy are performed. The different microstructures and the mechanical properties are compared. Mechanical behavior is determined based on quasi-static tensile tests and strain-controlled low cycle fatigue tests with total strain amplitudes εA of 0.35%, 0.5%, and 0.8%. The as-built and stress-relieved conditions meet the mechanical demands for the tensile properties of the international standard ISO 5832-11. Based on the Coffin–Manson–Basquin relation, fatigue strength and ductility coefficients, as well as exponents, are determined to examine fatigue life for the different conditions. The stress-relieved condition exhibits, overall, the best properties regarding monotonic tensile and cyclic fatigue behavior.</jats:p>}},
  author       = {{Hein, Maxwell and Kokalj, David and Lopes Dias, Nelson Filipe and Stangier, Dominic and Oltmanns, Hilke and Pramanik, Sudipta and Kietzmann, Manfred and Hoyer, Kay-Peter and Meißner, Jessica and Tillmann, Wolfgang and Schaper, Mirko}},
  issn         = {{2075-4701}},
  journal      = {{Metals}},
  keywords     = {{General Materials Science, Metals and Alloys, laser powder bed fusion, Ti-6Al-7Nb, titanium alloy, biomedical engineering, low cycle fatigue, microstructure, nanostructure}},
  number       = {{1}},
  publisher    = {{MDPI AG}},
  title        = {{{Low Cycle Fatigue Performance of Additively Processed and Heat-Treated Ti-6Al-7Nb Alloy for Biomedical Applications}}},
  doi          = {{10.3390/met12010122}},
  volume       = {{12}},
  year         = {{2022}},
}

@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}},
}

@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}},
}

@phdthesis{37579,
  abstract     = {{Leichtmetalle mit einem breiten Eigenschaftsspektrum gewährleisten die Realisierung ressourcenschonender Produkte und ermöglichen die Intensivierung sortenreiner Kreislaufwirtschaften. Die vorliegende Arbeit untersucht einen wärmeunterstützten Ansatz zur Erhöhung der Formgebungsgrenzen stark kaltverfestigter AlMg4,5 Blechwerkstoffe bei gleichzeitiger Beschränkung des Festigkeitsverlustes durch Erholungseffekte. Experimentelle Untersuchungen stellen eine wissenschaftlich fundierte Erkenntnisbasis über die werkstofftechnischen Wirkzusammenhänge des untersuchten Prozesses dar. Gepaart mit an realen Bauteilgeometrien validierten numerischen Simulationsmodellen legt diese Arbeit einen methodischen Grundstein für die industrielle Umsetzung des hier untersuchten Blechumformprozesses. Die erzielte mittlere Dehngrenze des exemplarisch untersuchten Bauteils übersteigt die Dehngrenze eines konventionellen AlMg4,5 Werkstoffes um 190 %. Mit 320 MPa entspricht sie dem Festigkeitsniveau des walzharten Blechhalbzeuges im Lieferzustand, ein Wert, der nach dem aktuellen Stand der Technik auf Bauteilebene ausschließlich mit aushärtbaren AlMgSi Legierungen darstellbar ist. }},
  author       = {{Camberg, Alan Adam}},
  isbn         = {{978-3-8440-8271-5}},
  keywords     = {{Aluminium, Blechumformung, AlMg, Materialmodellierung, Duktiles Versagen, Halbwarmumformung, Automobil, Leichtbau, Uni-Alloy, 5000-Serie, 5182, GISSMO}},
  pages        = {{230}},
  publisher    = {{Shaker Verlag}},
  title        = {{{Festigkeitssteigerung von Aluminiumblechformteilen der 5000-Serie durch Erweiterung der Formgebungsgrenzen stark kaltverfestigter Ausgangswerkstoffe}}},
  doi          = {{10.2370/9783844082715}},
  volume       = {{2021,52}},
  year         = {{2021}},
}

@article{24086,
  abstract     = {{Laser beam melting (LBM) is an advanced manufacturing technology providing
special features and the possibility to produce complex and individual parts directly
from a CAD model. TiAl6V4 is the most common used titanium alloy particularly
in biomedical applications. TiAl6Nb7 shows promising improvements especially
regarding biocompatible properties due to the substitution of the hazardous
vanadium. This work focuses on the examination of laser beam melted TiAl6Nb7.
For microstructural investigation scanning electron microscopy including energydispersive
x-ray spectroscopy as well as electron backscatter diffraction are utilized.
The laser beam melted related acicular microstructure as well as the corresponding
mechanical properties, which are determined by hardness measurements
and tensile tests, are investigated. The laser beam melted alloy meets,
except of breaking elongation A, the mechanical demands like ultimate tensile
strength Rm, yield strength Rp0.2, Vickers hardness HV of international standard
ISO 5832-11. Next steps contain comparison between TiAl6Nb7 and TiAl6V4 in
different conditions. Further investigations aim at improving mechanical properties
of TiAl6Nb7 by heat treatments and assessment of their influence on the microstructure
as well as examination regarding the corrosive behavior in human bodylike
conditions.}},
  author       = {{Hein, Maxwell and Hoyer, Kay-Peter and Schaper, Mirko}},
  issn         = {{0933-5137}},
  journal      = {{Materialwissenschaft und Werkstofftechnik}},
  keywords     = {{Laser beam melting, titanium alloy, TiAl6Nb7, biomedical engineering, implants}},
  pages        = {{703--716}},
  title        = {{{Additively processed TiAl6Nb7 alloy for biomedical applications}}},
  doi          = {{10.1002/mawe.202000288}},
  volume       = {{52}},
  year         = {{2021}},
}