Regensburg 2019 – wissenschaftliches Programm
MM 28.5: Topical Talk
Mittwoch, 3. April 2019, 16:45–17:15, H45
Recent advances in in situ TEM — •Christian Kübel1, C.N. Shyam Kumar1,2, Simone Dehm1, Ralph Krupke1,2, Manuel Konrad1, Wolfgang Wenzel1, Ankush Kashiwar1,2, and Horst Hahn1,2 — 1Karlsruhe Institute of Technology, Germany — 2Technical University Darmstadt, Germany
In situ TEM techniques have developed tremendously during the last decade, providing direct quantitative structural and morphological information to understand reactions and processes in nanocrystalline materials in response to an external stimulus. We will illustrate some of the possibilities in situ TEM provides to develop a deeper materials understanding and discuss the challenges in interpreting in situ results using two types of experiments:
1) Mechanical deformation of nanocrystalline Pd and Au thin films, directly imaging grain rotation and grain boundary migration during straining and relaxation, analyzing correlations between grains and a strong Bauschinger effect observed in these materials, looking at both local processes and a statistical ensemble.
2) Thermally induced growth of nanocrystalline graphene, investigating the mobility and reactions of small graphene flakes, in particular the role of defects in different types of merging and Ostwald-type ripening of graphene flakes, supported by molecular modelling.
The influence of sample preparation and, in particular, electron beam effects on processes, reactions and kinetics will be critically discussed, to derive the main materials properties from in situ TEM experiments.