High-resolution electron backscatter diffraction: an emerging tool for studying local deformation

Electron backscatter diffraction (EBSD) is a widely available and relatively easy-to-use scanning-electron-microscopy-based diffraction technique. Recently, Wilkinson, Meaden, and Dingley presented two papers on a new cross-correlation-based analysis of EBSD patterns which allow variations in the elastic strain and lattice rotation tensors to be measured at a sensitivity of about 10(-4) at high spatial resolution. This paper briefly describes the basis of the technique and how the resulting lattice curvatures can be used to estimate the geometrically necessary dislocation (GND) content in a sample. To illustrate the utility of the method for microscale deformation studies the following examples are described: first, nanoindentation near a grain boundary in alpha-Ti; second, transformation-induced GNDs in a dual-phase steel; third, thermally-induced and mechanically-induced deformation near carbides in a superalloy; fourth, GND accumulation during fatigue of a polycrystalline Ti-6Al-4V alloy.