Article
Nanoscience & Nanotechnology
A. Weidner, K. Fischer, H. Biermann
Summary: The study investigated the mechanical behavior, microstructure, and texture development of ultrafine-grained austenitic TRIP steels with different austenite stabilities. Through thermo-mechanical processing, a significant increase in yield strength was achieved due to the ultrafine-grained microstructure. The observed Lueders band phenomenon and texture evolution provide insights into the deformation behavior of these steels.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Multidisciplinary Sciences
J. Richter, G. Bartzsch, S. Scherbring, A. Bolender, M. Vollmer, J. Mola, O. Volkova, T. Niendorf
Summary: Metastable CrMnNi steels with different phase stabilities were manufactured using laser-based powder bed fusion process. Adequate material selection allows for tailoring mechanical properties and residual stress states, eliminating the need for thermal post-treatments. This study highlights the effectiveness of adapting materials to the process characteristics of additive manufacturing.
SCIENTIFIC REPORTS
(2022)
Article
Nanoscience & Nanotechnology
Atef Hamada, Ali Khosravifard, Sumit Ghosh, Matias Jaskari, Marion Kreins, Walaa Abd-Elaziem, Mohamed Wahba, Essam Ahmed, Tarek Allam
Summary: This study highlights the strengthening mechanisms observed during the metal joining of high-strength grade steels and provides insights into the microstructural features and mechanical strength evaluation. The results show that laser welding can induce fully martensitic structures and refined grains in the heat affected zone, leading to improved hardness.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
T. W. J. Kwok, P. Gong, R. Rose, D. Dye
Summary: Two different microstructures of medium Mn steel were obtained through different approaches in hot rolling mill, showing a simultaneous twinning induced plasticity and transformation induced plasticity (TWIP + TRIP) mechanism. However, twinning contributed relatively little to the strength of the alloy, mainly due to the small initial slip lengths that reduced the opportunity for grain work hardening.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Peng Liu, Xiaodong Hou, Chaoyun Yang, Yikun Luan, Chengwu Zheng, Dianzhong Li, Guangcai Ma
Summary: The microstructure evolution and austenite stability of Rare Earth (RE)-alloyed Transformation Induced Plasticity (TRIP) steels subjected to intercritical annealing and isothermal bainitic transformation have been investigated. The addition of minor RE elements refined the microstructure and affected the thermodynamics of austenite and bainite transformation. The retained austenite quantity and thermal stability were significantly elevated in RE-alloyed TRIP steels, leading to improved strength-ductility performance.
MATERIALS CHARACTERIZATION
(2023)
Article
Engineering, Industrial
Gregoire S. Larue, Vesna Popovic, Matthew Legge, Claire Brophy, Ross Blackman
Summary: Public transport systems are crucial services for urban environments, continuously evolving to support the successful and sustainable development of cities and regions. An investigation into historical records identified various factors contributing to slip, trip and fall incidents, including stairs, ramps, escalators, train entry and exit steps, doorway areas, and passenger rushing behaviors. Conducting a field study revealed a potential cause of passenger distraction and risky behavior to be a disconnect between needed and provided information, suggesting that improvements in information design could reduce the incidence of STFs.
APPLIED ERGONOMICS
(2021)
Article
Nanoscience & Nanotechnology
Christina Schroeder, Olena Volkova, Marco Wendler
Summary: This research investigates the temperature dependent mechanical properties of two types of stainless steels and finds that increasing strain rate decreases the ultimate tensile strength but has minimal effect on the uniform elongation of 4Mn. Additionally, 4Mn has a higher fraction of strain-induced alpha'-martensite compared to 1.4310.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Review
Engineering, Industrial
Jin Yang, J. P. Oliveira, Yulong Li, Caiwang Tan, Chenkai Gao, Yixuan Zhao, Zhishui Yu
Summary: The use of multi-material structures is an effective solution to reduce weight and emissions in the automotive industry. However, joining aluminum alloys to steels is challenging due to their mismatched properties. Laser-based processes have been explored to overcome this issue and this review examines the recent achievements and progress in this field, evaluating factors such as joining conditions, filler materials, microstructure, and mechanical properties.
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Victor H. Baltazar-Hernandez, Enrique A. Lopez-Baltazar, Francisco Alvarado-Hernandez, Salvador Gomez-Jimenez, Jose Jorge Ruiz-Mondragon, Elliot Biro, Norman Zhou
Summary: A study was conducted on the post-weld microstructure, hardness profile, and uniaxial tensile behavior of a transformation-induced plasticity (TRIP) steel and a dual-phase (DP) steel that were welded using gas metal arc welding (GMAW) and laser beam welding (LBW) processes. The results showed that the LBW specimen exhibited better elongation properties and higher ultimate tensile strength (UTS) compared to the GMAW specimen. The residual stress distribution along the weldment was also analyzed, with the LBW specimen showing lower residual stresses compared to the GMAW specimen. Furthermore, the tensile residual stresses in both welding processes did not affect the overall tensile properties of the weldments.
Article
Chemistry, Physical
V. Paranthaman, K. Shanmuga Sundaram, L. Natrayan
Summary: This study investigated the effect of SiC wt% on mechanical and microstructure behavior of TRIP 780 steels by resistance spot welding. Sample 4 exhibited equiaxed dimple and finer dendrites in the fusion zone, with maximum force and fracture energy.
Article
Engineering, Mechanical
Gang Zhu, Ya-Chun Wu, Ming-Liang Zhu, Fu-Zhen Xuan
Summary: The study conducted axial loaded cyclic tests on a precipitation-hardened martensitic steel at different stress ratios in 3% NaCl solution and steam environment, revealing apparent environmental effects on fatigue strength and crack initiation morphology. Fine granular areas were observed for the first time in the environmental media, showing dependence on local fracture mode.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Review
Engineering, Civil
M. B. Jablonska
Summary: This study discusses the temperature change of TWIP steels during deformation, as a result of the conversion of plastic deformation work into heat. The methods of measuring or modeling these temperature changes are presented. The study highlights that TWIP steels generate higher heat during plastic deformation compared to conventional steels, due to their higher yield stresses and limit strains. This heat has a significant impact on the microstructure and properties of the deformed material. It can lead to changes in deformation mechanisms and affect workability and energy consumption.
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING
(2023)
Review
Materials Science, Multidisciplinary
Lulu Guo, Lina Zhang, Joel Andersson, Olanrewaju Ojo
Summary: This paper reviews the latest research progress in additive manufacturing (AM) process of 18% nickel maraging steels, including L-PBF, L-DED, and WAAM. The emphasis is on the defects, structure, and mechanical properties of the additive manufactured 18% nickel maraging steels. The influences of processing parameters on defects formation, macrostructure, microstructure, and mechanical properties are outlined. The paper also provides future research directions for AM of 18% nickel maraging steel.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
Paul J. Burke, Fiona J. Beck, Emma Aisbett, Kenneth G. H. Baldwin, Matthew Stocks, John Pye, Mahesh Venkataraman, Janet Hunt, Xuemei Bai
Summary: The Asia-Pacific region has seen significant growth in energy use and is the largest emitter of greenhouse gases. Australia has been a major player in meeting the region's energy needs, but its exports contribute to a substantial amount of emissions. However, the country has the potential to become a key exporter of zero-carbon energy and products, contingent on cost reductions, growing demand, and the development of clean energy trade frameworks.
Article
Materials Science, Multidisciplinary
Fayez Al-Harbi, Azdiar A. Gazder, Elena Pereloma
Summary: The study found that the rate of transformation of retained austenite to martensite is faster in the Nb-Ti-containing steel compared to the base steel, mainly due to the co-location of most retained austenite with bainitic ferrite in the former. The stability of retained austenite in tension decreases in the order of: RA in bainite > RA at polygonal ferrite/bainite interfaces > RA embedded in polygonal ferrite grains and at polygonal ferrite triple junctions or grain boundaries. Fine grains of retained austenite may be less stable if located in unfavorable stress regions of the microstructure.
Article
Materials Science, Multidisciplinary
Marcel Mandel, Volodymyr Kietov, Robert Hornig, Malte Vollmer, Johanna-Maria Frenck, Christina Wuestefeld, David Rafaja, Thomas Niendorf, Lutz Krueger
Summary: The polarization behavior of Fe-34Mn-17Al-5Ni shape-memory alloy and pure Fe in NaCl-free and NaCl-contaminated Ca(OH)(2,sat) solutions were analyzed. It was found that FeMnAlNi exhibits more severe pitting corrosion sensitivity than Fe in NaCl-contaminated solutions. The pitting behavior is rationalized based on the different semiconducting properties of the passive oxides, analyzed by the Mott-Schottky technique.
Article
Materials Science, Multidisciplinary
Anton Salomon, Mykhaylo Motylenko, David Rafaja
Summary: The formation of reaction layers between corundum-based (Al2O3 + C) filter materials covered with functional Al2O3-C coatings having different carbon contents and molten steel 42CrMo4 is investigated at the reaction temperature of 1600 degrees C. Different layers are formed during the reaction process, starting with an amorphous reaction layer, followed by the formation of nanocrystalline phases and eventually a dense corundum layer with attached platelets. The effect of carbon content in the functional Al2O3-C coating on the nucleation and growth of corundum platelets is also discussed.
ADVANCED ENGINEERING MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
S. Martin, A. Weidner, C. Ullrich, C. Schimpf, M. Motylenko, R. Lehnert, H. Biermann, D. Rafaja, A. Vinogradov, Y. Estrin
Summary: This article explores the microstructural evolution and deformation mechanisms of high-alloy austenitic steel, demonstrating the impact of twin nucleation process on the strain hardening behavior. Experimental data and model predictions provide insights into the enhanced plasticity of the steel, with general guidelines for austenitic steel design established based on the findings.
MATERIALS CHARACTERIZATION
(2022)
Article
Engineering, Mechanical
L. Haus, M. Wildfeuer, J-E Grochowski, J. Wockel, M. Muller, F. Kohn, W. Schulz, C. Wustefeld, D. Rafaja, J. Albrecht
Summary: In this study, wear-resistant tungsten carbide thin films were deposited on steel substrates using magnetron sputtering in a mixed atmosphere. The excess carbon in the hard material layer was found to reduce the coefficient of friction by up to 40%, while increasing the volume of wear. Adjusting the acetylene supply and bias voltage influenced the film's composition and mechanical properties.
Article
Materials Science, Multidisciplinary
S. Martin, A. Winkelmann, A. Leineweber
Summary: This study demonstrates for the first time that the disordered eta phase transforms into the monoclinic eta phase with a characteristic twin-domain microstructure when the Cu-rich Cu6Sn5 intermetallic is ordered. Detailed Kikuchi diffraction pattern analysis is used to investigate the domain microstructure. The simulation-based Kikuchi diffraction pattern matching approach proves to be more sensitive to different domain orientations compared to the conventional EBSD analysis.
Article
Materials Science, Multidisciplinary
Andreas Leineweber, Max Fischer, Stefan Kante, Stefan Martin
Summary: Nitriding of Fe-1 wt.% Cu and Fe-5 wt.% Cu alloys at 813 K leads to the predominant formation of gamma '-iron nitride phase (gamma '-Fe4N) and epsilon-iron nitride phase (epsilon-Fe3N1+x) in pure alpha-Fe. The higher solubility of Cu in the gamma ' phase compared to the epsilon phase is attributed to the crystal structures of these phases.
Article
Crystallography
Alina Schramm, Martin Thummler, Olga Fabrichnaya, Simon Brehm, Jakob Kraus, Jens Kortus, David Rafaja, Christiane Scharf, Christos G. Aneziris
Summary: The aim of this study is to investigate the technological synthesis of MgAlON as a coating material for ceramic foam filters in the filtration of metal melts. The synthesis is carried out by calculating the thermodynamics and using different fractions of Al2O3, MgO, and AlN as starting materials. The influence of the components' quantity on the conversion degree is evaluated, along with the effect of holding time and composition points on the reaction. XRD analysis is performed to determine phase fractions and lattice parameters, and the applicability of the material is evaluated through sessile drop tests.
Article
Biochemistry & Molecular Biology
Marta Valaskova, Pavel Lestinsky, Lenka Matcjova, Katerina Klemencova, Michal Ritz, Christian Schimpf, Mykhailo Motylenko, David Rafaja, Jakub Belik
Summary: This study investigates the performance of hematite catalysts prepared through precipitation methods in the catalytic oxidation of methane. The results show that hydrohematites with smaller particle size and larger lattice volume, containing structurally incorporated water and vacancies, have a positive influence on the oxidation of methane.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Physical
S. Martin, D. Sulik, X. F. Fang, H. Becker, A. Leineweber
Summary: The microstructure of a successfully applied Al-Si bond coating for the interconnection of cast aluminum alloy with a conventional steel substrate is analyzed. The bond coating consists of a columnar Al layer attached to the steel substrate with an intermetallic layer. Silicon grains precipitate between the Al layer and the intermetallic phases, forming ternary compounds. Shear tests confirm the successful connection of the bond coating with the steel substrate.
Article
Materials Science, Multidisciplinary
Stefan Neumann, Azita Rezvani, Matthaeus Barasinski, Georg Garnweitner, Doris Segets, David Rafaja
Summary: This paper presents a multiscale approach using transmission electron microscopy (TEM) to study the characteristics of gold nanocrystals (NCs). The approach combines high-resolution TEM to observe the atomic-scale features of NCs with a semi-automatic analysis of low-magnification high-angle annular dark-field scanning TEM images to provide statistical information about the morphological attributes of NCs. The results of these complementary techniques are combined and correlated to quantify and understand the crystallographic orientations, configurations, and defects of different types of gold nanocrystals.
MICROSCOPY AND MICROANALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Christian Schimpf, Jonas Lachmann, Marius H. Wetzel, Peter D. B. Fischer, Andreas Leineweber, David Rafaja
Summary: This article introduces an escape room focused on materials science and crystallography, aiming to increase students' interest in these fields. The escape room appeals to participants with varying backgrounds through its variable difficulty and gameplay duration, and imparts lasting knowledge through reflection.
JOURNAL OF APPLIED CRYSTALLOGRAPHY
(2023)
Article
Chemistry, Physical
Matthias Krause, Mareen Hoppe, Carlos Romero-Muniz, Alvaro Mendez, Frans Munnik, Aurelio Garcia-Valenzuela, Christian Schimpf, David Rafaja, Ramon Escobar-Galindo
Summary: The stability of transparent conductive oxide SnO2:Ta (1.25 at% Ta) thin films was studied under isothermal conditions at 650°C and 800°C in air. The elemental composition and optical spectra remained unchanged after high-temperature treatment. X-ray diffraction confirmed the preservation of a single rutile-type phase. The presence of point defects, identified as Sn vacancies and O interstitials, was observed but did not affect the material's transmittance and reflectance.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Computer Science, Interdisciplinary Applications
Ulrike Ratayski, Christian Schimpf, Christina Wuestefeld, Anke Dalke, Horst Biermann, David Rafaja
Summary: The stability of an iron nitride compound layer formed by plasma nitriding of AISI D2 tool steel was investigated using in situ high-temperature X-ray diffraction. The compound layer decomposes and forms an alpha-Fe 'black' layer, with the decomposition process occurring in two steps.
ENGINEERING REPORTS
(2022)
Article
Computer Science, Interdisciplinary Applications
Anke Dalke, Tom Weinhold, Alexander Schramm, Christina Wuestefeld, Ulrike Ratayski, Vjaceslav Sochora, Horst Biermann, David Rafaja
Summary: The duplex treatment of plasma nitriding and physical vapor deposition improves the performance of forming tools. This study investigates the influence of nitriding on conventionally heat-treated tool steel and discusses the effect of the compound layer. Various characterization techniques reveal the relationships between different layers.
ENGINEERING REPORTS
(2022)
