A5041594909- Advanced Materials Characterization Techniques
- Machine Learning in Materials Science
- Ion-surface interactions and analysis
- High Temperature Alloys and Creep
- Force Microscopy Techniques and Applications
- Crystallography and molecular interactions
- Intermetallics and Advanced Alloy Properties
- Hydrogen embrittlement and corrosion behaviors in metals
- Advanced Chemical Physics Studies
- Computational Drug Discovery Methods
- Magnetic properties of thin films
- Advanced materials and composites
- Magnetic Properties and Applications
- Fusion materials and technologies
- Nuclear Materials and Properties
- Corrosion Behavior and Inhibition
- High Entropy Alloys Studies
- Scientific Measurement and Uncertainty Evaluation
- Integrated Circuits and Semiconductor Failure Analysis
- Additive Manufacturing Materials and Processes
- Microstructure and mechanical properties
Los Alamos National Laboratory
2024
Ruhr University Bochum
2018-2024
Abstract Pushing the maximum service temperature of aircraft engines and industrial gas turbines is major pathway to improve their energy efficiency reduce CO 2 emissions. This mostly limited by capability key-component materials, including superalloys. In this alloy class, segregation elements facilitates plastic deformation generally considered cause softening during high-temperature deformation. Here, we show that segregation-assisted processes can also lead strengthening induce an...
Abstract Directly imaging all atoms constituting a material and, maybe more importantly, crystalline defects that dictate materials’ properties, remains formidable challenge. Here, we propose new approach to chemistry-sensitive field-ion microscopy (FIM) combining FIM with time-of-flight mass-spectrometry ( tof-ms ). Elemental identification and correlation images enabled by data mining of combined delivers truly analytical-FIM (A-FIM). Contrast variations due different chemistries is also...
Interatomic potentials provide a means to simulate extended length and time scales that are outside the reach of ab initio calculations. The development an interatomic potential for particular material requires optimization parameters functional form potential. We present parametrization protocol analytic bond-order (BOPs) provides physically transparent computationally efficient description interaction. BOP follows derivation along coarse-graining electronic structure from...
The use of high-dimensional regression techniques from machine learning has significantly improved the quantitative accuracy interatomic potentials. Atomic simulations can now plausibly target predictions in a variety settings, which brought renewed interest robust means to quantify uncertainties on simulation results. In many practical encompassing both classical and large class potentials, dominant form uncertainty is currently not due lack training data but misspecification, namely...
Abstract The development of new Ni-base superalloys with a complex composition consisting eight or more alloying elements is challenging task. experimental state-of-the-art cycle based on the adaption already existing compositions. Although alloy compositions potentially improved material properties are expected to be similar known superalloys, this procedure impedes efficiently finding these in large multi-dimensional design-space all elements. Modern combines numerical optimization methods...
For large-scale atomistic simulations of magnetic materials, the interplay atomic and degrees freedom needs to be described with high computational efficiency. Here we present an analytic bond-order potential (BOP) for iron-cobalt, interatomic based on a coarse-grained description electronic structure. We fitted BOP parameters non-magnetic density functional theory (DFT) calculations Fe, Co, Fe-Co bulk phases. Our captures structure nonmagnetic It provides accurate predictions structural...
A quantitative descriptor of local atomic environments is often required for the analysis atomistic data. Descriptors environment ideally provide physically and chemically intuitive insight. This requires descriptors that are low-dimensional representations interplay between geometry electronic bond formation. The moments density states relate structure to chemistry. makes it possible construct based have an immediate relation binding energy. We show a moments-descriptor sufficient as lowest...
Hydrogen enhanced decohesion is expected to play a major role in ferritic steels, especially at grain boundaries. Here, we address the effects of some common alloying elements C, V, Cr, and Mn on H segregation behaviour mechanism Σ 5 ( 310 ) [ 001 ] 36.9 ∘ boundary bcc Fe using spin polarized density functional theory calculations. We find that enhance cohesion. Furthermore, all have an influence energies interstitial as well these elements’ impact V slightly promotes cohesion enhancing...
The Cr-Co-Ni system was studied by combining experimental and computational methods to investigate phase stability mechanical properties. Thin-film materials libraries were prepared quenched from high temperatures up 700 °C using a novel quenching technique. It could be shown that wide A1 solid solution region exists in the system. To validate results obtained thin-film libraries, bulk samples of selected compositions arc melting, data additionally compared DFT calculations. are good...
In contrast to their empirical counterparts, machine-learning interatomic potentials (MLIAPs) promise deliver near-quantum accuracy over broad regions of configuration space. However, due generic functional forms and extreme flexibility, they can catastrophically fail capture the properties novel, out-of-sample configurations, making quality training set a determining factor, especially when investigating materials under conditions. present study, we propose novel automated dataset...
Abstract Stacking faults (SFs) are important structural defects that play an essential role in the deformation of engineering alloys. However, direct observation SFs at atomic scale can be challenging. Here, we use analytical field ion microscopy, including density functional theory–informed contrast estimation, to image local elemental segregation a creep-deformed solid-solution single-crystal alloy Ni–2 at% W. The segregated atoms imaged brightly, and time-of-flight spectrometry allows for...
Stacking faults (SF) are important structural defects that play an essential role in the deformation of engineering alloys. However, direct observation stacking at atomic scale can be challenging. Here, we use analytical field ion microscopy (aFIM), including density-functional theory informed contrast estimation, to image local elemental segregation SFs a creep-deformed solid solution single crystal alloy Ni-2 at.% W. The segregated atoms imaged brightly, and time-of-flight spectrometry...
Interatomic potentials provide a means to simulate extended length and time scales that are outside the reach of ab initio calculations. The development an interatomic potential for particular material requires optimization parameters functional form potential. We present parameterization protocol analytic bond-order (BOP) physically transparent computationally efficient description interaction. BOP follows derivation along coarse-graining electronic structure from density-functional theory...
Directly imaging all atoms constituting a material and, maybe more importantly, crystalline defects that dictate materials' properties, remains formidable challenge. Here, we propose new approach to chemistry-sensitive field-ion microscopy (FIM) combining contrast interpretation from density-functional theory (DFT) and elemental identification enabled by time-of-flight mass-spectrometry data mining. Analytical-FIM has true atomic resolution demonstrate how the technique can reveal presence...
For large-scale atomistic simulations of magnetic materials, the interplay atomic and degrees freedom needs to be described with high computational efficiency. Here we present an analytic bond-order potential (BOP) for iron-cobalt, interatomic based on a coarse-grained description electronic structure. We fitted BOP parameters non-magnetic density-functional theory (DFT) calculations Fe, Co, Fe-Co bulk phases. Our captures structure It provides accurate predictions structural stability,...