@article{47122, abstract = {{AbstractFeCo alloys are important materials used in pumps and motors in the offshore oil and gas drilling industry. These alloys are subjected to marine environments with a high NaCl concentration, therefore, corrosion and catastrophic failure are anticipated. So, the surface dissolution of additively manufactured FeCo samples is investigated in a quasi-in situ manner, in particular, the pitting corrosion in 5.0 wt pct NaCl solution. The local dissolution of the same sample region is monitored after 24, 72, and 168 hours. Here, the formation of rectangular and circular pits of ultra-fine dimensions (less than 0.5 µm) is observed with increasing immersion time. In addition, the formation of a corrosion-inhibiting surface layer is detected on the sample surface. Surface dissolution leads to a change in the surface structure, however, no change in grain shape or grain size is noticed. The surface topography after local dissolution is correlated to the grain orientation. Quasi-in situ analysis shows the preferential dissolution of high-angle grain boundaries (HAGBs) leading to a change in the fraction of HAGBs and low-angle grain boundaries fraction (LAGBs). For the FeCo sample, a potentiodynamic polarisation test reveals a corrosion potential (Ecorr) of − 0.475 V referred to the standard hydrogen electrode (SHE) and a corrosion exchange current density (icorr) of 0.0848 A/m2. Furthermore, quasi-in situ experiments showed that grains oriented along certain crystallographic directions are corroding more compared to other grains leading to a significant decrease in the local surface height. Grains with a plane normal close to the $$\langle {1}00\rangle$$ ⟨ 100 ⟩ direction reveal lower surface dissolution and higher corrosion resistance, whereas planes normal close to the $$\langle {11}0\rangle$$ ⟨ 110 ⟩ direction and the $$\langle {111}\rangle$$ ⟨ 111 ⟩ direction exhibit a higher surface dissolution.}}, author = {{Pramanik, Sudipta and Krüger, Jan Tobias and Schaper, Mirko and Hoyer, Kay-Peter}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, keywords = {{Metals and Alloys, Mechanics of Materials, Condensed Matter Physics}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Quasi-In Situ Localized Corrosion of an Additively Manufactured FeCo Alloy in 5 Wt Pct NaCl Solution}}}, doi = {{10.1007/s11661-023-07186-7}}, year = {{2023}}, } @article{36327, abstract = {{AbstractWith an innovative optical characterization method, using high-temperature digital image correlation in combination with thermal imaging, the local change in strain and change in temperature could be determined during thermo-mechanical treatment of flat steel specimens. With data obtained by this optical method, the transformation kinetics for every area of interest along the whole measuring length of a flat specimen could be analyzed by the generation of dilatation curves. The benefit of this innovative optical characterization method compared to a dilatometer test is that the experimental effort for the design of a tailored component could be strongly reduced to the investigation of only a few tailored thermo-mechanical processed specimens. Due to the implementation of a strain and/or temperature gradient within the flat specimen, less metallographic samples are prepared for hardness analysis and analysis of the microstructural composition by scanning electron microscopy to investigate the influence of different process parameters. Compared to performed dilatometer tests in this study, the optical method obtained comparable results for the transformation start and end temperatures. For the final design of a part with tailored properties, the optical method is suitable for a time-efficient material characterization. Graphical Abstract}}, author = {{Reitz, Alexander and Grydin, Olexandr and Schaper, Mirko}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, keywords = {{Metals and Alloys, Mechanics of Materials, Condensed Matter Physics}}, number = {{8}}, pages = {{3125--3142}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Optical Detection of Phase Transformations in Steels: An Innovative Method for Time-Efficient Material Characterization During Tailored Thermo-mechanical Processing of a Press Hardening Steel}}}, doi = {{10.1007/s11661-022-06732-z}}, volume = {{53}}, year = {{2022}}, } @article{23797, abstract = {{Abstract Safety-relevant components in automobiles require materials that combine high strength with sufficient residual ductility and high-energy absorption. A graded thermo-mechanical treatment of the press-hardening steel 22MnB5 with graded microstructure can provide a material with such properties. Different austenitization temperatures, cooling and forming conditions within a sheet part lead to the development of microstructures with mixed phase compositions. To determine the resulting phase contents in such graded processed parts, a large number of dilatometric tests are usually required. With a non-contact characterization method, it is possible to detect local phase transformations on an inhomogeneously treated flat steel specimen. For press-hardening steel after heat treatment and thermo-mechanical processing, correlations between austenitization temperature, hot deformation strain, microstructure, and hardness are established.}}, author = {{Reitz, Alexander and Grydin, Olexandr and Schaper, Mirko}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, pages = {{5628--5638}}, publisher = {{Springer}}, title = {{{Characterization of Phase Transformations During Graded Thermo-Mechanical Processing of Press-Hardening Sheet Steel 22MnB5}}}, doi = {{10.1007/s11661-020-05976-x}}, year = {{2020}}, } @article{15964, author = {{Leuders, Stefan and Vollmer, Malte and Brenne, Florian and Tröster, Thomas and Niendorf, Thomas}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, pages = {{3816--3823}}, title = {{{Fatigue Strength Prediction for Titanium Alloy TiAl6V4 Manufactured by Selective Laser Melting}}}, doi = {{10.1007/s11661-015-2864-x}}, year = {{2015}}, } @article{41534, author = {{Niendorf, Thomas and Brenne, Florian and Hoyer, Kay-Peter and Schwarze, Dieter and Schaper, Mirko and Grothe, Richard and Wiesener, Markus and Grundmeier, Guido and Maier, Hans Jürgen}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, keywords = {{Metals and Alloys, Mechanics of Materials, Condensed Matter Physics}}, number = {{7}}, pages = {{2829--2833}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Processing of New Materials by Additive Manufacturing: Iron-Based Alloys Containing Silver for Biomedical Applications}}}, doi = {{10.1007/s11661-015-2932-2}}, volume = {{46}}, year = {{2015}}, } @article{24112, author = {{Niendorf, Thomas and Brenne, Florian and Hoyer, Kay-Peter and Schwarze, Dieter and Schaper, Mirko and Grothe, Richard and Wiesener, Markus and Grundmeier, Guido and Maier, Hans Jürgen}}, issn = {{1073-5623}}, journal = {{Metallurgical and Materials Transactions A}}, pages = {{2829--2833}}, title = {{{Processing of New Materials by Additive Manufacturing: Iron-Based Alloys Containing Silver for Biomedical Applications}}}, doi = {{10.1007/s11661-015-2932-2}}, year = {{2015}}, }