A5067758794- Advanced Materials Characterization Techniques
- Hydrogen embrittlement and corrosion behaviors in metals
- Microstructure and mechanical properties
- Aluminum Alloy Microstructure Properties
- Diamond and Carbon-based Materials Research
- Fusion materials and technologies
- Metal and Thin Film Mechanics
- Force Microscopy Techniques and Applications
- Aluminum Alloys Composites Properties
- Intermetallics and Advanced Alloy Properties
- Ion-surface interactions and analysis
- Microstructure and Mechanical Properties of Steels
- Electron and X-Ray Spectroscopy Techniques
- Nuclear Materials and Properties
- Magnesium Alloys: Properties and Applications
- nanoparticles nucleation surface interactions
- Magnetic properties of thin films
- Electronic and Structural Properties of Oxides
- Advanced materials and composites
- Advanced Surface Polishing Techniques
- Additive Manufacturing Materials and Processes
- Magnetic Properties of Alloys
- Advanced Electron Microscopy Techniques and Applications
- Photorefractive and Nonlinear Optics
- Nuclear Physics and Applications
ETH Zurich
2014-2024
University of Louisiana at Lafayette
2021
Board of the Swiss Federal Institutes of Technology
2020
Max-Planck-Institut für Nachhaltige Materialien
2010-2013
Max Planck Society
2010-2011
Cambridge Scientific (United States)
2006-2011
Cameca (United States)
2010
National Yang Ming Chiao Tung University
2008
Northwestern University
2002-2005
Los Alamos National Laboratory
1998-1999
Heavy hydrogen gets frozen in place Hydrogen embrittlement contributes to the failure of steel a wide variety everyday applications. Various strategies mitigate embrittlement, such as adding carbides into steel, are hard validate because we unable map atoms. Chen et al. combined fluxing samples with deuterium and cryogenic transfer protocol minimize diffusion, allowing for detailed structural analysis (see Perspective by Cairney). Their findings revealed trapped cores carbide precipitates....
Ultrathin passive films effectively prevent the chemical attack of stainless steel grades in corrosive environments; their stability depends on interplay between structure and chemistry constituents iron, chromium, molybdenum (Fe-Cr-Mo). Carbon (C), eventually boron (B), are also important steels, although small quantities. In particular, nanoscale inhomogeneities along surface can have an impact material failure but still poorly understood. Addressing a stainless-type glass-forming...
We demonstrate experimentally that a part-per-million addition of Sn solutes in Al-Mg-Si alloys can inhibit natural aging and enhance artificial aging. The mechanism controlling the is argued to be vacancy diffusion, with trapping vacancies at low temperature releasing them elevated temperature, which supported by thermodynamic model first-principles computations Sn-vacancy binding. This "diffusion on demand" solves long-standing problem detrimental alloys, great scientific industrial...
This review gives an overview of the effects clusters in various aluminum alloys. Characterization methods are discussed general and results for important AlMgSi alloys presented detail. Indirect characterization methods, such as hardness, tensile testing, electrical resistivity, differential scanning calorimetry, positron annihilation spectroscopy discussed, well atom probe tomography direct measurement clusters. A particular focus is set on tomography, where possible artifacts influencing...
While lean Mg–Zn–Ca alloys are promising materials for temporary implants, questions remain on the impact of Zn and Ca microstructure. In this context, precipitation in Mg-1.5Zn-0.25Ca (in wt.%), initially extruded at 330°C, towards Mg–Ca binary precipitates or Ca–Mg–Zn ternary was probed a multiscale correlative approach using atom probe tomography (APT) analytical transmission electron microscopy (TEM). Particular focus set precipitate phase whose structure is debated. as-extruded...
Abstract As hydrogen is touted as a key player in the decarbonization of modern society, it critical to enable quantitative (H) analysis at high spatial resolution and, if possible, atomic scale. H has known deleterious impact on mechanical properties (strength, ductility, toughness) most materials that can hinder their use part infrastructure hydrogen-based economy. Enabling mapping including local concentration analyses specific microstructural features essential for understanding multiple...
A key question in materials science is how fast properties evolve, which relates to the kinetics of phase transformations. In metals, primarily connected diffusion, for substitutional elements enabled via mobile atomic-lattice vacancies. fact, non-equilibrium vacancies are often required structural changes. Rapid quenching various important alloys, such as Al- or Mg-alloys, results example natural aging, i.e. slight movements solute atoms material, significantly alter material properties....
Standard atom probe tomography spatial reconstruction techniques have been reasonably successful in reproducing single crystal datasets. However, artefacts persist the reconstructions that can be attributed to incorrect assumption of a spherical evaporation surface. Using simulated and experimental field evaporation, we examine expected shape evaporating surface propose use variable point projection position mitigate some degree these artefacts. We show initial results from an implementation...
Abstract Environmental control during transfer between instruments is required for samples sensitive to air or thermal exposure prevent morphological chemical changes prior analysis. Atom probe tomography a rapidly expanding technique three-dimensional structural and analysis, but commercial remain limited loading specimens under ambient conditions. In this study, we describe multifunctional environmental hub allowing controlled cryogenic room-temperature of atmospheric vacuum pressure...
Passivation of grain boundaries (GBs) and interfaces to suppress recombination improve minority carrier lifetime (MCLT) is essential for the functionality devices based on polycrystalline materials. Improvement MCLT believed be a very promising way bring CdTe solar cells next efficiency level. However, which parameters significantly affect not well understood. Here, high‐efficiency in an unconventional inverted structure are used approach this issue. Advanced characterization tools such as...
Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – 7,
Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – 30,
Reduced activation ferritic/martensitic steels (RAFMs), such as Eurofer 97 and F82H, are designed to enhance the high-temperature strength by forming fine dispersive particles of MX phase. However, stability phase is still not fully understood. The objective this study determine irradiation effects on F82H. experiments were performed at Swiss Spallation Neutron Source (SINQ) a temperature ∼300 °C dose ∼20 dpa. current work reveals effect an atomic scale atom probe tomography (APT). one hand...
Local electrode atom probe (LEAP) tomography of Al-catalyzed silicon nanowires synthesized by the vapor–liquid–solid method is presented. The concentration Al within nanowire was found to be 2 × 1020 cm−3, which higher than expected solubility limit for in Si at growth temperature 550 °C. Reconstructions contained indicate a denuded region adjacent catalyst/Si interface, while clusters are distributed throughout rest nanowire.