Ambient grain orientation imaging on complex surfaces

Crystal orientation imaging is generally confined to the laboratory, typically following destructive sectioning, with most current techniques reliant on electron-material interactions that require a vacuum. This information is gathered in a manner that requires careful planning, however a more desirable approach would allow the manufacturer to acquire this data non-destructively at the point of manufacture, with little or no time penalty. We show that coupling a numerically controlled etching method to topographical data processing can be used to spatially map grain orientations over planar and non-planar surfaces. Our method allows the construction of large area orientation maps (≈400 mm2) in agreement with electron backscatter diffraction datasets. We have characterised spatial and angular resolution limits for the technique, which are correlated to length scales of microscale etch surfaces and our ability to measure their geometries. This approach has the potential to augment materials processing technologies, where resultant microstructures require strict control in order to guarantee through-life integrity.