Crystal orientation and detector distance effects on resolving pseudosymmetry by electron backscatter diffraction

Abstract

Accurately indexing pseudosymmetric materials has long proven challenging for electron backscatter diffraction. The recent emergence of intensity-based indexing approaches promises an enhanced ability to resolve pseudosymmetry compared with traditional Hough-based indexing approaches. However, little work has been done to understand the effects of sample position and orientation on the ability to resolve pseudosymmetry, especially for intensity-based indexing approaches. Thus, in this work the effects of crystal orientation and detector distance in a model tetragonal ZrO2 (c/a = 1.0185) material are quantitatively investigated. The orientations that are easiest and most difficult to correctly index are identified, the effect of detector distance on indexing confidence is characterized, and these trends are analyzed on the basis of the appearance of specific zone axes in the diffraction patterns. The findings also point to the clear benefit of shorter detector distances for resolving pseudosymmetry using intensity-based indexing approaches.

Crystallography of Fe–Mn–Al–Ni Shape Memory Alloys

“…d-f Pole figures from the region highlighted by a white solid line in a-c, showing the average austenite (A2) orientation and the indicated predicted and measured martensite (A1) orientations, revealing incorrect indexing also for some uniformly indexed regions, e.g., those colored in dark pink in c fct poles are located in the proximity of {110} A2 poles (and {100} A1/fct close to {100} A2 ) as demonstrated in Figure 6e, f is an example how some bias (e.g., uncorrected distortions in the EBSD pattern) might lead the indexing algorithm favoring an incorrect solution. It has not yet been tested whether there is some systematic crystal orientation dependence of the success rate for correct indexing as worked out recently for another tetragonal material with cubic pseudosymmetry [39].…”

Automatic detection of Kikuchi bands based on Radon transform and PPHT

“…Dictionary‐based orientation refinement is another method to measure orientation of EBSD, for example, Refs. 26, 27 and 28. These dictionary‐based methods are based on the idea of image matching, where orientation refinement is achieved by matching template patterns.…”