Abstract text (incl. figure legends and references)
Electron backscatter diffraction (EBSD) is a widespread microanalytical method to characterize crystal orientations, phases and defects in typically polycrystalline materials. At the core facility ScopeM, we are supporting user requests in a diversity of applications, also involving characterization by EBSD. Thus, in the first part of this presentation, a number of projects are presented, with emphasis on the links between microstructures and textures to the anisotropy of physical properties, and the effects of different processing routes for tuning them to the most desired properties. These in include the microstructural characterization and elastic anisotropy of additively manufactured Ni-based superalloys (1-4) produced by powder bed laser fusion (PBLF or SLM); crystal orientation dependent photoelectrochemical performance of thermally-oxidised Cu2O photocathodes (5); grain orientation dependent catalyzed surface reactions observed by in-situ experiments (6); twinning mediated plasticity in lean Mg alloys (7); bi-modal nanoheteroepitaxy of GaAs on Si (8).
In the second part, a few recent developments are highlighted. As one of the general bottlenecks, EBSD is typically performed on 2D surfaces of bulk materials. Thus, planar features in three-dimensional microstructures, like interface planes or grain boundaries, are only accessible by their traces on the planar sample surface. A number of approaches has been applied to reveal the missing degree of freedom in order to obtain the complete 5-parameter grain boundary character in a statistically reliable population. These could be pseudo-3D EBSD (9); habit plane analysis (10); hybrid analysis by EBSD and optical reflectance on top and bottom sides (11); large number statistics on 2D mappings (12-14); and serial sectioning by (P)FIB, fs-laser or polishing robots (15-18). Finally, not only speed and sensitivity of EBSD detectors continue to see major developments. Also, the processing of EBSD patterns has advanced from conventional Hough transform based band detection and indexing to pattern matching approaches, where the recorded patterns are compared to the best-fit from a dictionary of simulated patterns (19-20). In the case of quartz microstructures, these simulations demonstrate the potential of EBSD to distinguish not only Dauphiné twin orientations (21-22), but even the handedness of left-handed and right-handed crystals (23), and polarity in other non-centrosymmetric structures.