In situ Microscopy
Mechanical properties are not only the most important physical properties of structural materials, they are also determining the reliability of functional materials such as used in energy conversion and storage or used in actuators or sensors. Besides plasticity also fatigue and fracture might cause mechanical degradation or even failure and therefore are the origin of the loss of functionality in functional systems. The mechanical properties are a direct consequence of the behaviour of crystal defects, e.g. dislocations. Thus, understanding the characteristics and mechanisms of crystal defects under mechanical stress is key to improve and optimize the mechanical and functional properties of material systems.
The vision of in situ microscopy group is exploring the fundamental degradation mechanisms at the micro- and nanoscale under various stimuli and correlating it with functional properties. For this purpose, we employ in situ deformation methods, such as tension and compression in SEM/TEM, high-temperature deformation, nanoindentation, or microcantilever fracture test, to facilitate understanding the underlying mechanical degradation of material systems. Combined with advanced imaging techniques, degradation processes of functional materials, such as microcracking or delamination of interfaces, can be also directly observed and analyzed under dynamic operating conditions using in situ electrical biasing tests.