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Electron backscatter diffraction (EBSD) is a widely available and relatively easy-touse 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 24 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 a-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.

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Microstructure and crystallography of δ phase hydrides in as-received fine grain and 'blocky alpha' large grain Zircaloy-4 (average grain size ~11 µm and >200 µm, respectively) were examined using electron backscatter diffraction. Results suggest that the matrix-hydride orientation relationship is {0001} ||{111} ; < 112 ̅ 0 > || < 110 > for all the cases studied. The habit plane of intragranular hydrides and some intergranular hydrides has been found to be {101 ̅ 7} of the surrounding matrix. The morphology of intergranular hydrides can vary depending upon the angle between the grain boundary and the hydride habit plane. The misfit strain between α-Zr and δ-hydride is accommodated by high density of dislocations and twin structures in the hydrides, and a mechanism of twin formation in the hydrides has been proposed. The growth of hydrides across grain boundaries is achieved through an autocatalytic manner similar to the growth pattern of intragranular hydrides. Easy collective shear along < 11 ̅ 00 > makes it possible for hydride nucleation at any grain boundaries, while the process seems to favour grain boundaries with low (<40°) and high (>80°) c-axis misorientation angles. Moreover, the angle between the grain boundary and the adjacent basal planes does not influence the propensity for hydride nucleation.

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