Weighted Burgers Vector analysis of orientation fields from high-angular resolution electron backscatter diffraction.

Gardner, Joe ORCID: 0000-0002-8593-0201, Wallis, David, Hansen, Lars N and Wheeler, John ORCID: 0000-0002-7576-4465 (2024) Weighted Burgers Vector analysis of orientation fields from high-angular resolution electron backscatter diffraction. Ultramicroscopy, 257. 113893-.

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Official URL: http://dx.doi.org/10.1016/j.ultramic.2023.113893

Abstract

The Weighted Burgers Vector (WBV) method can extract information about dislocation types and densities present in distorted crystalline materials from electron backscatter diffraction (EBSD) maps, using no assumptions about which slip systems might be present. Furthermore, high-angular resolution EBSD (HR-EBSD) uses a cross-correlation procedure to increase the angular precision of EBSD measurements by an order of magnitude compared to conventional EBSD. However, the WBV technique has not previously been applied to HR-EBSD data and therefore it remains unclear as to which low-angle substructures can be reliably characterised by WBV analysis of conventional EBSD data and which require additional HR-EBSD processing. To establish some practical examples that can be used to guide future data-acquisition strategies, we compare the output of the WBV method when applied to conventional EBSD data and HR-EBSD data collected from the most common minerals in Earth's lower crust (plagioclase feldspar) and upper mantle (olivine). The results demonstrate that HR-EBSD and WBV processing are complementary techniques. The increase in angular precision achieved with HR-EBSD processing allows low-angle (on the order of 0.1°) structures, which are obscured by noise in conventional EBSD data, to be analyzed quantitatively using the WBV method. Combining the WBV and HR-EBSD methods increases the precision of calculated WBV directions, which is essential when using information about active slip systems to infer likely deformation mechanisms from naturally deformed microstructures. This increase in precision is particularly important for low-symmetry crystals, such as plagioclase, that have a wide range of available slip systems that vary in relative activity with changing pressure, temperature and differential stress. Because WBV directions are calculated using no assumptions about which slip systems may be present, combining this technique with HR-EBSD to refine the precision of lattice orientation gradients is ideal for investigating complex natural materials with unknown deformation histories.

Item Type:	Article
Uncontrolled Keywords:	Geometrically necessary dislocations, High-angular resolution electron backscatter diffraction, Misorientation, Olivine, Plagioclase, Weighted Burgers Vector
Divisions:	Faculty of Science and Engineering > School of Environmental Sciences
Depositing User:	Symplectic Admin
Date Deposited:	19 Dec 2023 15:06
Last Modified:	01 Mar 2024 14:55
DOI:	10.1016/j.ultramic.2023.113893
Open Access URL:	https://doi.org/10.1016/j.ultramic.2023.113893
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3177540