Features of Transmission EBSD and its Application

Abstract

Features of transmission electron backscatter diffraction (EBSD) observation with a standard EBSD (s-EBSD) detector are surveyed in this study. Heavily deformed Al and 8Cr tempered martensite transmission electron microscope (TEM) specimens were used for this study. It is shown that a specimen tilt angle of $30°-40°in the opposite direction of the usual 70°and a smaller working distance in the range 4 mm-5 mm are recommended when using a s-EBSD detector. Specimen thickness and accelerating voltage (Acc.V) have a strong affect on the quality of transmission EBSD patterns and orientation maps. Higher Acc.Vs are generally recommended to get good quality orientation maps. In case of very thin specimens, lowering the Acc.Vs will give better results. In the observation of a thin film of an 8Cr tempered martensite steel specimen, it is confirmed that t-EBSD can provide images and detailed quantitative orientation data comparable with that obtained by TEM. It is also shown that small precipitates of Cr 23 C 6 with sizes around 30 nm could be detected and their orientations measured.

On‐axis versus off‐axis Transmission Kikuchi Diffraction technique: application to the characterisation of severe plastic deformation‐induced ultrafine‐grained microstructures

“…The incident intensity corresponding to the different objective aperture diameters were measured with a Faraday‐cup. For the conventional configuration, a slight tilt of the thin foil was suggested in other works (Keller & Geiss, ; Brodusch et al ., ,b; Suzuki, ; Van Bremen et al ., ). For this reason, orientation maps on the same sample area were produced at three tilt angles (0°, –10°, –20°), keeping all other settings, and especially the pattern centre, unchanged.…”

A method to correct coordinate distortion in EBSD maps

“…Similar to ECC techniques, TEM is orientation sensitive, and has normally a very high spatial resolution. The surface condition for TEM samples are in most cases suitable for direct EBSD measurements [14][15][16]. Since the acquisition time for TEM images is in the order of seconds, the spatial distortion in the images caused by beam drift is very small.…”

“…The drift problems become more critical when EBSD techniques are used together with other techniques, such as electron channeling contrast (ECC) and transmission electron microscopy (TEM), to characterize the same microstructures [14][15][16][17]. Due to the different imaging principles and acquisition time, the same microstructure characterized by EBSD can easily be more distorted than that with ECC/TEM.…”

Imaging with a Commercial Electron Backscatter Diffraction (EBSD) Camera in a Scanning Electron Microscope: A Review

“…It uses a commercial EBSD camera to collect the transmitted diffracted electrons to produce transmission Kikuchi patterns [39][40][41]. This technique is capable of using the full EBSD data processing capabilities on thin electron transparent specimens, in addition to dramatically improving the spatial resolution of orientation mapping to values directly comparable with those obtained with a transmission electron microscope (TEM) [21,22,42,43]. However, the data collected using this technique has not been utilized to its real potential, since most of the work reported so far was concentrated on acquiring orientation or phase maps.…”