MSE 2022
Lecture
28.09.2022
Estimating geometrically necessary dislocations from Kikuchi patterns
AC

Dr.-Ing. Ashish Chauniyal

Deutsches Zentrum für Luft- und Raumfahrt e.V.

Chauniyal, A. (Speaker)¹; Stricker, M.¹; Thome, P.¹
¹Ruhr-Universität Bochum
Vorschau
19 Min. Untertitel (CC)


Electron backscatter diffraction (EBSD) is widely used to determine local orientations of crystalline specimen that are determined at points of a regular grid. Each grid point produces a diffraction or Kikuchi pattern, which can be used to associate the point to a particular crystal orientation. Orientation differences or misorientations, are frequently used to identify grains in a specimen after post-processing. Moreover, since a small orientation difference can also arise due to changes in lattice curvature, they can be used to estimate the amount of geometrically necessary dislocations (GNDs). This method is essentially an indirect measurement of GNDs even though the defect density information is already embedded in a Kikuchi pattern, but very hard to decipher. In this work we attempt to disentangle the defect information in a Kikuchi pattern by comparing simulated and experimental patterns. Several defect free simulated patterns are used to reconstruct patterns with defects, using image reconstruction methods. We then corroborate our findings using patterns obtained from experiments to establish a correlation between Kickuchi patterns and dislocation content.

Abstract

Abstract

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