A5048159154- Microstructure and Mechanical Properties of Steels
- Metal Alloys Wear and Properties
- Metallurgy and Material Forming
- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- Advanced Materials Characterization Techniques
- Hydrogen embrittlement and corrosion behaviors in metals
- Magnetic Properties and Applications
- Ferroelectric and Piezoelectric Materials
- Magnetic properties of thin films
- Advanced materials and composites
- Inorganic Chemistry and Materials
- Electron and X-Ray Spectroscopy Techniques
- Pulsars and Gravitational Waves Research
- Semiconductor materials and interfaces
- High Temperature Alloys and Creep
- Aluminum Alloy Microstructure Properties
- Advanced Memory and Neural Computing
- Semiconductor materials and devices
- Geophysics and Sensor Technology
- Advanced Frequency and Time Standards
- Surface and Thin Film Phenomena
- Titanium Alloys Microstructure and Properties
- Radiative Heat Transfer Studies
- Non-Destructive Testing Techniques
Dillinger Hütte (Germany)
2019-2023
Saarland University
2008-2022
Walter de Gruyter (Germany)
2022
Max Planck Institute for Intelligent Systems
2008-2013
Max Planck Society
2008-2012
The competition between collective quantum phases in materials with strongly correlated electrons depends sensitively on the dimensionality of electron system, which is difficult to control by standard solid-state chemistry. We have fabricated superlattices paramagnetic metal lanthanum nickelate (LaNiO(3)) and wide-gap insulator aluminate (LaAlO(3)) atomically precise layer sequences. used optical ellipsometry low-energy muon spin rotation show that LaNiO(3) as thin two unit cells undergo a...
Scanning transmission electron microscopy in combination with energy-loss spectroscopy is used to study LaNiO3/LaAlO3 superlattices grown on (La,Sr)AlO4 varying single-layer thicknesses, which are known control their electronic properties. The microstructure of the films investigated atomic level and role observed defects discussed context different Two types Ruddlesden-Popper faults found, either two or three dimensional. common planar fault induced by steps substrate surface. In contrast,...
We have studied the microstructure of LaNiO3-LaAlO3 superlattices using transmission electron microscopy in combination with energy loss spectroscopy. In grown on non-polar SrTiO3 substrates, nanometer-sized NiO precipitates form directly at interface between substrate and initial LaNiO3 layer, while control measurements polar substrates show no NiO. Because drastically different electronic properties LaNiO3, such can strongly affect atomically thin LaNiO3-based films multilayers SrTiO3....
The synergetic effect on hardenability by combining boron with other microalloying elements (such as Nb, Mo and Nb + Mo) is widely known for high-strength medium carbon steels produced direct quenching subsequent tempering treatment. improvement of mechanical properties could be reached through optimization different mechanisms, such solid solution hardening, unit size refinement, strain fine precipitation hardening the in solution. current study proposes a procedure evaluating contribution...
The microalloying with niobium (Nb) and titanium (Ti) is standardly applied in low carbon steel high-strength low-alloy (HSLA) steels enables austenite conditioning during thermo-mechanical controlled processing (TMCP), which results pronounced grain refinement the finished steel. In that respect, it important to better understand precipitation kinetics as well sequence a typical Nb-Ti-microalloyed Various characterization methods were utilized this study for tracing microalloy after...
Abstract Heavy plate steels with bainitic microstructures are widely used in industry due to their good combination of strength and toughness. However, obtaining optimal mechanical properties is often challenging the complex multiple phase constitutions caused by different cooling rates through thickness. Here, both conventional advanced microstructural characterization techniques which bridge meso- atomic-scales were applied investigate how microstructure/mechanical property-relationships a...
Solubility of mixed niobium-titanium carbonitrides in commercially relevant High-Strength Low-Alloy (HSLA) steel was investigated by combined use electrical resistivity measurements and APT after interrupted quenching from soaking temperatures between 950 1250 °C. Increasing the bulk material towards higher proportional to nominal niobium addition which varied 0.002 0.022–0.043–0.085 wt.-%. Correlative analysis solutes matrix showed good agreement with resistivity. Investigating numerous...
Multilayers composed of 5×(6.4nmFe∕5.6nmPt) were annealed at temperatures up to 735°C. The intermixing was analyzed by analytical and high-resolution transmission electron microscopy. Intermixing full ordering the L10 structure completed after annealing temperature dependence is best described a three-step process including diffusion through diluted alloys during initial (400–500°C), L12-ordered (around 600°C), in final L10-ordered film above 700°C.
A combined synchrotron X-ray diffraction and transmission electron microscopy study reveals a structural phase transition controlled by the overall thickness of epitaxial nickelate-aluminate superlattices. The between uniform twin-domain states is confined to nickelate layers leaves aluminate unaffected.
Recently, advanced thermomechanical hot rolling schedules followed by direct quenching are being developed in order to avoid reheating and treatment after eliminate an energy cost consuming step. The use of boron as alloying element is a widely known practice high strength medium carbon steels increase the due its potential for delaying phase transformation improving hardenability. In addition, significant synergetic effect on hardenability could be reached combining B with microalloying...
Abstract The prior austenite grain size (PAGS) represents one of the most significant microstructural parameters for steel research and process development. Since PAGS directly correlates with recrystallisation during rolling in manufacturing plates, it has a huge influence on its mechanical properties. Methods to determine reliably reproducibly are high demand. There several different approaches, based working principles, aiming measure PAGS. In this paper, focus will be held chemical...
Microalloying of low carbon steel with niobium (Nb) and titanium (Ti) is standardly applied in high-strength low-alloy (HSLA) steels enabling austenite conditioning during thermo-mechanical controlled processing (TMCP), which results pronounced grain refinement the finished steel. The metallurgical effects microalloying elements are related solute drag precipitate particle pinning, both acting on boundary thereby delaying or suppressing recrystallization deformed grain. In that respect it...
Abstract This work has focused on the study of hot working behavior boron high strength steels microalloyed with different combinations Nb and/or Mo. The role and Mo during deformation low carbon is well known: both mainly retard austenite recrystallization, leading to pancaked microstructures before phase transformation refined room temperature microstructures. However, design rolling schedules resulting in properly conditioned microstructures, requires microstructural evolution models that...
Abstract The application of direct quenching after hot rolling plates is being employed in the production ultra-high-strength rolled plates. When heavy gauge are produced, complexity involve achieving high cooling rates plate core increased and formation undesirable soft phases within martensite common. In current paper, both conventional (DQ CQ) processing routes were reproduced by dilatometry tests continuous transformation (CCT) diagrams built for four different high-strength boron...
The dynamic recrystallization behavior of ultra-high strength boron-microalloyed steels optionally alloyed with niobium and molybdenum is analyzed in this paper. Multipass torsion tests were performed to simulate plate rolling conditions followed by direct quenching. influence alloy composition on the transformed microstructure was evaluated means EBSD, thereby characterizing morphology austenite grain after roughing finishing passes. results indicated that for Nb-microalloyed steel, partial...
Abstract The strength and toughness of low alloyed ferritic/bainitic steels depend on their microstructure, which evolves during thermo‐mechanical treatments along the processing chain. Chromium‐molybdenum steel microstructures are complex. Therefore, only a limited number attempts have been made to fully characterize carbide populations in such steels. In present work, analytical transmission electron microscopy is employed study microstructure chromium‐molybdenum steel, features ferritic...
The substitution of conventionally quenched and tempered (Q&T) plates by thermomechanically treated ultra-high strength steels is becoming widely accepted in industry.Austenite conditioning during rolling followed Direct Quenching (DQ) might offer benefits mechanical properties.The metallurgical mechanisms behind these different routes, though, are not clear; especially when combinations microalloying elements such as B, Mo and/or Nb combined.Deformation dilatometry studies were performed...