Characterization at high spatial and angular resolutions of deformed nanostructures by on-axis HR-TKD

Abstract

Global Digital Image Correlation (DIC) is applied on the electron diffraction patterns acquired by the "on-axis" Transmission Kikuchi Diffraction (TKD) technique. High-angular resolution (HR-TKD) mappings of the grain internal disorientations and the associated geometrically necessary dislocation densities are then derived at a nanoscale resolution. Tailored for the fine characterization of nanomaterials in the scanning electron microscope (SEM), the method is illustrated on a nanostructured high-purity aluminium processed by severe plastic deformation (SPD) and its performances are discussed in the light of imaging by transmission electron microscopy (TEM) and by SEM using a forescatter electron detector (FSD).

Characterization of a nanopipe dislocation in GaN by means of HR-EBSD and field dislocation mechanics analysis

“…We focus our study on a nanopipe in GaN, to test a recent High-Resolution Electron Backscatter Diffraction (HR-EBSD) method developed in our team [10][11][12] and implemented in our analysis software ATEX [13]. Elastic strains and rotations are assessed to within 1 × 10 −4 (in ideal experimental conditions) from precise knowledge of the projection geometry and the displacement field between two highresolution (≈1 Mpx) Kikuchi electron diffraction patterns, a reference one and a target one.…”

Building on Gleiter: The Foundations and Future of Deformation Processing of Nanocrystalline Metals

“…Recent advances in methods such as high-resolution transmission Kikuchi diffraction (HR-TKD) offer the possibility for unprecedented insights. [237][238][239][240][241] Concurrently, our ability to simulate and measure the grain boundary properties and deformation physics is essential within the hierarchical framework of mechanisms needed to control property improvements. 2.…”

Conditions near a crack tip: Advanced experiments for dislocation analysis and local strain measurement

“…Fundenberger et al 34 introduced an “on-axis” configuration, which enables faster acquisition time, lower pattern distortion, and a slightly better spatial resolution compared to the conventional “off-axis” configuration. By coupling the cross-correlation algorithms and on-axis TKD, Ernould et al 35 could investigate the grain internal disorientations and GND densities of a nanocrystalline pure aluminum. Wang et al 36 reported that by applying a monolithic active pixel sensor-based direct electron detector, high-quality EBSD patterns or high-speed pattern acquisition (up to 5988 fps) can be achieved.…”