Automated electron back-scatter diffraction (EBSD) techniques have been available for almost 20 years. They are routinely used for surface characterization of crystalline samples for the determination of lattice orientation, phase and overall texture. To a lesser extent, geometrically necessary dislocation (GND) content has been extracted from the local orientation gradient (curvature), and some efforts have been made to determine elastic strain. However, recent advances in crosscorrelation techniques for determining distortion between EBSD patterns have led to new possibilities for detail extraction. Not only can orientation information be ascertained at much higher resolution compared with traditional EBSD, but GND content can now be determined with improved precision, and elastic strain can be acquired with higher confidence. This chapter will review the microstructure information that can be recovered from both legacy EBSD and the more recent high-resolution EBSD (HREBSD) frameworks. Introduction to Traditional EBSDEBSD techniques analyze back-scatter diffraction patterns for information regarding atomic lattice structure. In a typical setup a polished crystalline sample is held at a tilt of 70 • from horizontal under an electron beam of a scanning electron microscope (SEM) with energy in the range 5-30 keV. 405Strain and Dislocation Gradients from Diffraction Downloaded from www.worldscientific.com by PURDUE UNIVERSITY on 04/12/15. For personal use only.

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