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The angular resolution of electron backscatter diffraction (EBSD) measurements can be significantly improved using an analysis based on determination of small shifts in features from one pattern to the next using cross-correlation functions. Using pattern shift measurements at many regions of the pattern, errors in the best fit strain and rotation tensors can be reduced. The authors show that elements of the strain tensor and small misorientations can be measured to ±10 -4 and ±0.006° for rotations. We apply the technique to two quite different materials systems. First, we determine the elastic strain distribution near the interface in a cross-sectioned SiGe epilayer, Si substrate semiconductor heterostructure. The plane stress boundary conditions at the sample surface are used to separate every term in the strain tensor. Second, the applicability to structural materials is illustrated by determining the lattice curvature caused by dislocations within the plastic zone associated with the wake and tip of a fatigue crack in a Ni based superalloy. The lattice curvatures are used to calculate the geometrically necessary dislocation content in the plastic zone. © 2006 Institute of Materials, Minerals and Mining.

This paper describes progress in improving the spatial resolution of the well-established Orientation Imaging Microscopy technique, OIM, by developing an analogous procedure for the transmission electron microscope. The transmission orientation micrographs are obtained by recording a large series of dark field micrographs taken from the chosen area in the specimen. This area is selected so that it contains all of the grains of interest and is imaged at sufficiently high magnification to yield the spatial resolution required. The changing intensity of each pixel in different dark field micrographs permits the equivalent of a diffraction pattern for that pixel to be constructed. This enables determination of the lattice orientation of small volumes in the sample corresponding to that imaged in each individual pixel. Experimentation has shown that problems arise however, that decrease the fraction of correctly measured points due to ambiguities in determining the index of higher order reflections, especially when the total number of reflections observed is small. The solution has been to both modify the indexing procedure and to sum the diffraction vectors observed within a single grain. The paper concentrates on a detailed analysis of a heavily deformed aluminium sample, chosen because of the fragmentation of the structure.

Orientation Imaging Microscopy (OIM) in the scanning electron microscope (SEM) has proven itself to be a powerful tool for investigating local orientation relationships in polycrystalline microstructures. Because of the inherent limitations of electron backscatter diffraction in the SEM, the OIM technique is limited to the investigation of structures at the micron scale. A parallel technique for the transmission electron microscope (TEM) would enable similar studies of local orientation relationships in smaller scale structures to be performed. This report reviews development work on adapting the OIM technique to the TEM using dark field imaging and presents some preliminary results.

A new microscopy, called Orientation Imaging Microscopy, is described. Imaging results from precise measurements of local lattice orientation rapidly obtained by Backscattered Kikuchi Diffraction. The hardware configuration of the microscope is described and a description of image formation presented. Applications to several materials of differing lattice structure are described. Connections of the microscopy with various aspects of modern texture analysis are emphasized.

In this paper, we describe the use of electron back scatter diffraction (EBSD) to study strain variations in crystalline samples at the nanoscale. The analysis relies on cross correlation measurements of small shifts in the EBSD pattern measured at many points dispersed across the pattern. The method allows the full strain tensor, and lattice rotations to be obtained at a sensitivity of ∼10 -4. The method is applied to study variations of strains and rotations near the surface of 200 nm thick epitaxial layers of Si 0.85Ge 0.15 grown on a Si substrate patterned with rectangular and square mesa. Linescans across rectangular mesas show that strain relaxation and accompanying lattice rotations are restricted to the edges of wide mesas but that the relaxation extends across the entirety of mesas narrower than ∼6 μm. Two dimensional maps of the strain variation in a ∼3 μm wide square mesa are also presented. © 2008 Elsevier Ltd. All rights reserved.

Ni n /Fe n multilayers have been grown, in Ultra High Vacuum (UHV) conditions, on 150 nm Cu(111) single crystals grown, in-situ, on mica(0001) substrates. Modulation wavelength ranged from 2 n = 30 monolayers (ML) to 2 n = 6 ML. X-ray diffractometry of samples showed satellite peaks corresponding to a range of modulations implying that the layering was incommensurate. Cross-sectional Transmission Electron Microscopy (TEM) confirmed layering persisted even at modulations of n = 3 ML. Plan view TEM electron diffraction showed a transition from fcc(111)/fcc(111) to fcc(111)/bcc(110) layering as n increased. The transition was not sharp but progressive with a midpoint at about n = 10 ML. Room temperature measurements of saturated magnetic moment per volume, using a vibrating sample magnetometer, varied with modulation layer thickness. The moment per volume for the fcc material with a [111] plane spacing of 0.2059 nm (equivalent to a lattice parameter of 0.357 nm) was a factor of three less than for an homogeneous NiFe alloy. It is noted that this lattice parameter coincides with the range predicted by theorists for a change in fcc Fe-Fe magnetic coupling.