@article{41501, author = {{Tillmann, Wolfgang and Lopes Dias, Nelson Filipe and Kokalj, David and Stangier, Dominic and Hein, Maxwell and Hoyer, Kay-Peter and Schaper, Mirko and Gödecke, Daria and Oltmanns, Hilke and Meißner, Jessica}}, issn = {{0167-577X}}, journal = {{Materials Letters}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, publisher = {{Elsevier BV}}, title = {{{Tribo-functional PVD thin films deposited onto additively manufactured Ti6Al7Nb for biomedical applications}}}, doi = {{10.1016/j.matlet.2022.132384}}, volume = {{321}}, year = {{2022}}, } @article{30103, author = {{Huang, Jingyuan and Orive, Alejandro Gonzalez and Krüger, Jan Tobias and Hoyer, Kay-Peter and Keller, Adrian and Grundmeier, Guido}}, issn = {{0010-938X}}, journal = {{Corrosion Science}}, keywords = {{General Materials Science, General Chemical Engineering, General Chemistry}}, pages = {{110186}}, publisher = {{Elsevier BV}}, title = {{{Influence of proteins on the corrosion of a conventional and selective laser beam melted FeMn alloy in physiological electrolytes}}}, doi = {{10.1016/j.corsci.2022.110186}}, volume = {{200}}, year = {{2022}}, } @article{41502, author = {{Teng, Zhenjie and Wu, Haoran and Pramanik, Sudipta and Hoyer, Kay-Peter and Schaper, Mirko and Zhang, Hanlong and Boller, Christian and Starke, Peter}}, issn = {{1438-1656}}, journal = {{Advanced Engineering Materials}}, keywords = {{Condensed Matter Physics, General Materials Science}}, number = {{9}}, publisher = {{Wiley}}, title = {{{Characterization and Analysis of Plastic Instability in an Ultrafine‐Grained Medium Mn TRIP Steel}}}, doi = {{10.1002/adem.202200022}}, volume = {{24}}, year = {{2022}}, } @article{41504, author = {{Huang, Jingyuan and Gonzalez Orive, Alejandro and Krüger, Jan Tobias and Hoyer, Kay-Peter and Keller, Adrian and Grundmeier, Guido}}, issn = {{0010-938X}}, journal = {{Corrosion Science}}, keywords = {{General Materials Science, General Chemical Engineering, General Chemistry}}, publisher = {{Elsevier BV}}, title = {{{Influence of proteins on the corrosion of a conventional and selective laser beam melted FeMn alloy in physiological electrolytes}}}, doi = {{10.1016/j.corsci.2022.110186}}, volume = {{200}}, year = {{2022}}, } @article{41493, author = {{Krüger, Jan Tobias and Hoyer, Kay-Peter and Andreiev, Anatolii and Schaper, Mirko and Zinn, Carolin}}, issn = {{1438-1656}}, journal = {{Advanced Engineering Materials}}, keywords = {{Condensed Matter Physics, General Materials Science}}, publisher = {{Wiley}}, title = {{{Modification of Iron with Degradable Silver Phases Processed via Laser Beam Melting for Implants with Adapted Degradation Rate}}}, doi = {{10.1002/adem.202201008}}, 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}}, } @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}}, } @article{41510, author = {{Pramanik, Sudipta and Andreiev, Anatolii and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{0142-1123}}, journal = {{International Journal of Fatigue}}, keywords = {{Industrial and Manufacturing Engineering, Mechanical Engineering, Mechanics of Materials, General Materials Science, Modeling and Simulation}}, publisher = {{Elsevier BV}}, title = {{{Quasi in-situ analysis of fracture path during cyclic loading of double-edged U notched additively manufactured FeCo alloy}}}, doi = {{10.1016/j.ijfatigue.2021.106498}}, volume = {{153}}, year = {{2021}}, } @article{41509, author = {{Krüger, Jan Tobias and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{0167-577X}}, journal = {{Materials Letters}}, keywords = {{Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science}}, publisher = {{Elsevier BV}}, title = {{{Bioresorbable AgCe and AgCeLa alloys for adapted Fe-based implants}}}, doi = {{10.1016/j.matlet.2021.130890}}, volume = {{306}}, year = {{2021}}, } @article{41517, abstract = {{AbstractWithin this research, the multiscale microstructural evolution before and after the tensile test of a FeCo alloy is addressed. X-ray µ-computer tomography (CT), electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM) are employed to determine the microstructure on different length scales. Microstructural evolution is studied by performing EBSD of the same area before and after the tensile test. As a result, $$\langle$$ ⟨ 001$$\rangle$$ ⟩ ||TD, $$\langle$$ ⟨ 011$$\rangle$$ ⟩ ||TD are hard orientations and $$\langle$$ ⟨ 111$$\rangle$$ ⟩ ||TD is soft orientations for deformation accommodation. It is not possible to predict the deformation of a single grain with the Taylor model. However, the Taylor model accurately predicts the orientation of all grains after deformation. {123}$$\langle$$ ⟨ 111$$\rangle$$ ⟩ is the most active slip system, and {112}$$\langle$$ ⟨ 111$$\rangle$$ ⟩ is the least active slip system. Both EBSD micrographs show grain subdivision after tensile testing. TEM images show the formation of dislocation cells. Correlative HRTEM images show unresolved lattice fringes at dislocation cell boundaries, whereas resolved lattice fringes are observed at dislocation cell interior. Since Schmid’s law is unable to predict the deformation behavior of grains, the boundary slip transmission accurately predicts the grain deformation behavior.}}, author = {{Pramanik, Sudipta and Tasche, Lennart and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{1059-9495}}, journal = {{Journal of Materials Engineering and Performance}}, keywords = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}}, number = {{11}}, pages = {{8048--8056}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Correlation between Taylor Model Prediction and Transmission Electron Microscopy-Based Microstructural Investigations of Quasi-In Situ Tensile Deformation of Additively Manufactured FeCo Alloy}}}, doi = {{10.1007/s11665-021-06065-9}}, volume = {{30}}, year = {{2021}}, } @article{24243, abstract = {{The addition of Ag to amorphous carbon (a-C) films is highly effective in tailoring the tribo-mechanical properties and biocompatibility. For biomedical applications, Ag-containing a-C (a-C:Ag) represents a promising film material for improving the biofunctional surface properties of Ti-based alloys. In a sputtering process, a-C:Ag films, with Ag contents up to 7.5 at.%, were deposited with a chemically graded TixCy interlayer onto Ti6Al4V. The tribo-mechanical and biocompatible properties of a-C:Ag were evaluated. The influence of the Ag content on these properties was analyzed and compared to those of uncoated Ti6Al4V. Raman spectroscopy reveals that the amount of incorporated Ag does not induce significant structural changes in the disordered network, only a reduced number of vacancies and sp3-coordinated C bonds within the sp2-dominant a-C network is assigned to the films with high Ag concentration. With increasing Ag content, stresses, hardness, and elastic modulus decrease from (2.02 ± 0.07) to (1.15 ± 0.03) GPa, from (17.4 ± 1.5) to (13.4 ± 0.9) GPa, and from (171.8 ± 8.1) to (138.5 ± 5.8) GPa, respectively. In tribometer tests, the friction behavior against Al2O3 in lubricated condition with a simulated-body-fluid-based lubricant is not affected by the Ag concentration, but the Al2O3 counterpart wear is reduced for all a-C:Ag films compared to a-C. The friction against ultra-high-molecular-weight polyethylene (UHMWPE) decreases continuously with increasing Ag concentration and the counterpart wear is lower at higher Ag contents. Compared to a-C:Ag, Ti6Al4V demonstrates lower friction against UHMWPE and higher friction against Al2O3. The a-C:Ag films are not exposed to abrasion by Al2O3 or pronounced material transfer of UHMWPE. The hardness difference and chemical affinity between the friction partners are decisive for the tribological behavior of a-C:Ag. Compared to Ti6Al4V, the a-C:Ag films show antibacterial activity against Staphylococcus aureus, while the proliferation of osteoblast-like cells is reduced by Ag.}}, 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}}, title = {{{Tribo-mechanical properties and biocompatibility of Ag-containing amorphous carbon films deposited onto Ti6Al4V}}}, doi = {{10.1016/j.surfcoat.2021.127384}}, 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}}, } @article{41514, author = {{Krüger, Jan Tobias and Hoyer, Kay-Peter and Filor, Viviane and Pramanik, Sudipta and Kietzmann, Manfred and Meißner, Jessica and Schaper, Mirko}}, issn = {{0925-8388}}, journal = {{Journal of Alloys and Compounds}}, keywords = {{Materials Chemistry, Metals and Alloys, Mechanical Engineering, Mechanics of Materials}}, publisher = {{Elsevier BV}}, title = {{{Novel AgCa and AgCaLa alloys for Fe-based bioresorbable implants with adapted degradation}}}, doi = {{10.1016/j.jallcom.2021.159544}}, volume = {{871}}, year = {{2021}}, } @article{41515, author = {{Pramanik, Sudipta and Tasche, Lennart and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{2214-8604}}, journal = {{Additive Manufacturing}}, keywords = {{Industrial and Manufacturing Engineering, Engineering (miscellaneous), General Materials Science, Biomedical Engineering}}, publisher = {{Elsevier BV}}, title = {{{Investigating the microstructure of an additively manufactured FeCo alloy: an electron microscopy study}}}, doi = {{10.1016/j.addma.2021.102087}}, volume = {{46}}, year = {{2021}}, } @article{24090, abstract = {{AbstractWithin this research, the multiscale microstructural evolution before and after the tensile test of a FeCo alloy is addressed. X-ray µ-computer tomography (CT), electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM) are employed to determine the microstructure on different length scales. Microstructural evolution is studied by performing EBSD of the same area before and after the tensile test. As a result, $$\langle$$ ⟨ 001$$\rangle$$ ⟩ ||TD, $$\langle$$ ⟨ 011$$\rangle$$ ⟩ ||TD are hard orientations and $$\langle$$ ⟨ 111$$\rangle$$ ⟩ ||TD is soft orientations for deformation accommodation. It is not possible to predict the deformation of a single grain with the Taylor model. However, the Taylor model accurately predicts the orientation of all grains after deformation. {123}$$\langle$$ ⟨ 111$$\rangle$$ ⟩ is the most active slip system, and {112}$$\langle$$ ⟨ 111$$\rangle$$ ⟩ is the least active slip system. Both EBSD micrographs show grain subdivision after tensile testing. TEM images show the formation of dislocation cells. Correlative HRTEM images show unresolved lattice fringes at dislocation cell boundaries, whereas resolved lattice fringes are observed at dislocation cell interior. Since Schmid’s law is unable to predict the deformation behavior of grains, the boundary slip transmission accurately predicts the grain deformation behavior.}}, author = {{Pramanik, Sudipta and Tasche, Lennart and Hoyer, Kay-Peter and Schaper, Mirko}}, issn = {{1059-9495}}, journal = {{Journal of Materials Engineering and Performance}}, title = {{{Correlation between Taylor Model Prediction and Transmission Electron Microscopy-Based Microstructural Investigations of Quasi-In Situ Tensile Deformation of Additively Manufactured FeCo Alloy}}}, doi = {{10.1007/s11665-021-06065-9}}, year = {{2021}}, }