The characterization of low‐angle boundaries by EBSD

Bate, Pete S.; Knutsen, R.D.; Brough, I.; Humphreys, F.J.

doi:10.1111/j.1365-2818.2005.01513.x

Cited by 69 publications

(51 citation statements)

References 10 publications

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“…Orientation filtering of the data does help to reduce the influence of the orientation noise [57,58], but only to a limited extent. The effect of orientation noise on accurate subgrain detection is exacerbated by the fact that an apparent gradual change of orientation is often found as the electron beam is moved across boundaries of very low misorientation angle [59]. Preliminary studies show that such artificial gradients are found for boundaries with misorientation angle less than approximately 4°.…”

Section: Subgrain Reconstructionmentioning

confidence: 99%

Characterization and influence of deformation microstructure heterogeneity on recrystallization

Godfrey

Mishin

2015

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The microstructure resulting from plastic deformation of metals typically contains heterogeneity on several length scales. This is also true for samples deformed to large strains, where an important form of heterogeneity is in the variation in microstructural refinement by high angle boundaries. A methodology for quantifying this type of heterogeneity based on the identification of areas classified as low misorientation regions (LMRs) is described, and some parameters for quantification of both the extent and length scale of LMRs are presented. It is then shown how this approach can be used to investigate the early stages of recrystallization in samples deformed to large strains, by direct comparison of electron backscatter diffraction (EBSD) maps of the same area before and after annealing. Methods for estimation of the stored energy of deformation from EBSD data are also surveyed and the problems of each for quantification of the local variation in stored energy are discussed, where it is concluded that a method based on the summation of the contributions from individual boundary segments is considered to be the best suited at present for characterization of the local variation in stored energy on the scale of the dislocation boundary features.

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Section: Subgrain Reconstructionmentioning

confidence: 99%

Characterization and influence of deformation microstructure heterogeneity on recrystallization

Godfrey

Mishin

2015

IOP Conf. Ser.: Mater. Sci. Eng.

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“…The EBSD pattern recorded and indexed by traditional OIM is actually an average of the information contained within the interaction volume. Using known parameters the approximate interaction volume diameter can be simulated, and has been found by various authors to be in the range of 50-100 nm for heavier metals (Fe, Ni, Cu) and 100-200 nm for lighter metals (Al, Mg) [7,8]. The concomitant spatial resolution is dependent on how precisely mixed patterns near grain boundaries can be distinguished, and is often approximated as half the interaction volume diameter [9].…”

Section: Ebsd Overviewmentioning

confidence: 98%

Techniques and Applications of the Simulated Pattern Adaptation of Wilkinson’s Method for Advanced Microstructure Analysis and Characterization of Plastic Deformation

et al. 2010

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Electron Backscatter Diffraction (EBSD) based Orientation Imaging Microscopy (OIM) is used routinely at~500 materials laboratories worldwide for the characterization and development of diverse crystalline materials. Statistically significant data sets (~10 7 individual EBSD measurements) can be collected and analyzed within time periods of acceptable beam stability (~10 5 s). However, limitations in angular and spatial resolution have motivated a continued search for more robust EBSD-based methods. Herein is a gathered presentation of advanced techniques in use, intended as a guide to researchers in selecting the most appropriate method for their work. Wilkinson's method has been shown to increase angular resolution nearly two orders of magnitude to ±0.006°, facilitating measurement of elastic strain, lattice curvature, and dislocation density. A simulated pattern adaptation of Wilkinson's method extends these measurement capabilities to polycrystalline materials, by avoiding the need for an experimental strain free reference pattern. The angular resolution limit obtained is~0.04°. Accurate pattern center calibration, essential to the high resolution methods, is accomplished by parallelization of band edges projected onto a sphere centered at the interaction volume. FFT powered cross-correlation functions improve the spatial resolution near grain boundaries and correct for measurement inaccuracies induced by overlapping patterns. To corroborate these claims, exemplary results taken from a wedge-indented nickel single crystal, cold-worked copper polycrystal, and rolled nickel polycrystal are shown.

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“…misorientation angles in the range 0-2°) is present, even for perfect crystals [32]. Real misorientations <2°c an, therefore, not be reliably resolved using the current technique [32,33].…”

Section: Intragranular Defectsmentioning

confidence: 99%