© Dagmar Fischer
Research Group for Thin Film Materials Science
To address the relationships between synthesis, chemistry, structure, properties and performance in structural, nanoscale and functional materials, we integrate experimental and computational studies with all the aspects of materials science from developing the fundamental understanding to the design, synthesis and testing of new materials.
Specifically, our research focuses on a detailed atomic-level understanding of the microstructure-properties relations, kinetic processes, mass transport mechanisms, chemical reaction paths, material thermodynamics and phase transitions. We use a wide variety of in-situ as well as ex-situ characterization tools such as scanning electron microscopy (SEM) equipped with analytical techniques, differential scanning calorimetry (DSC), X-ray diffraction (XRD), submicron synchrotron X-ray tomographic microscopy (SXRTM), and high resolution transmission electron microscopy (HRTEM). Computational studies involve density functional theory (DFT), molecular dynamics (MD), TEM image simulations, and continuum mechanics.
We need to go nano! It will change (is changing) our world.
Nanostructured materials are composed of single- or multi-phase components whose characteristic size is in the nanometer range (1-50 nm). Typically, a distinction is made between lamellar, rod-like and equiaxed nanostructures (nanoscale extension in one, two and three dimensions).
Nanoscale material systems – due to their significantly different physical, chemical, and biological properties – possess new phenomena, structures, and processes.
Progress in nanoscience and technology depends largely on the systematic organization, manipulation, and characterization of nanostructures, where interfaces in particular play a primary role.
The fundamental study of structural and property relationships in materials and layers represents a central theme of our research activities. This not only places high demands on the understanding of the processes taking place in materials science, but also requires the use of state-of-the-art analytical methods. For example, nanostructures with a characteristic length of only a few nm can be investigated with high-resolution transmission electron microscopy.
A nano-scale structure allows the combination of different material properties (e.g., high strength combined with high toughness). Conventional metals and coatings are characterized by defects (e.g. dislocations) in their crystals. Under stress, these 'dislocations' migrate, causing plastic deformation, and this is even more pronounced at elevated temperatures (this is exploited in the forging of iron). Nanostructures act against this plastic deformation in two ways. On the one hand, the interfaces of the nanocrystals put an obstacle to the 'dislocation motion', and on the other hand, crystals with a size of only a few nanometers are too small for them.
Understanding the processes occurring during loading allows tailored property-design of hard coatings.
Such nanostructured materials and coatings are already used as tools (milling cutters, drills, cutting inserts, hobs) and coatings for mechanical processing involving high thermal and mechanical stress. The same is true for components in the automotive, aerospace and aeronautics industries, such as piston rings, valves and turbine blades. But also in optoelectronics, such as light emitting diodes (LEDs).
Future research focuses on the design of nanostructured materials and coatings for special applications in which multifunctional tasks are performed by the material and the coating.
google: Paul Mayrhofer, opens an external URL in a new window orcid: , opens an external URL in a new window0000-0001-7328-933, opens an external URL in a new window3 Prophy: prophy/833800, opens an external URL in a new window Publons: A-9640-2011, opens an external URL in a new window RG: Paul Mayrhofer, opens an external URL in a new window SC: 7003622599, opens an external URL in a new window