The effect of length scale on the determination of geometrically necessary dislocations via EBSD continuum dislocation microscopy

• Published in: Ultramicroscopy Vol. 164; no. C; pp. 1 - 10
• Main Authors: Ruggles, T.J., Rampton, T.M., Khosravani, A., Fullwood, D.T.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2016; Elsevier
• Subjects: Continuum dislocation microscopy; Continuums; Criteria; Density; Dislocation density; Dislocations; EBSD step size; Electron back scatter diffraction; High resolution EBSD; Mathematical models; Microscopy; Samples; High resolution EBSD; Continuum dislocation microscopy; Dislocation density; EBSD step size
• ISSN: 0304-3991; 1879-2723
• DOI: 10.1016/j.ultramic.2016.03.003

Electron backscatter diffraction (EBSD) dislocation microscopy is an important, emerging field in metals characterization. Currently, calculation of geometrically necessary dislocation (GND) density is problematic because it has been shown to depend on the step size of the EBSD scan used to investigate the sample. This paper models the change in calculated GND density as a function of step size statistically. The model provides selection criteria for EBSD step size as well as an estimate of the total dislocation content. Evaluation of a heterogeneously deformed tantalum specimen is used to asses the method. •The GND to SSD transition with increasing step size is analytically modeled.•Dislocation density of a microindented tantalum single crystal is measured.•Guidelines for step size selection in EBSD dislocation microscopy are presented.