Multi scale hard x-ray microscopy

Abstract

The structure of crystalline materials is typically organised hierarchically on several length scales. Hard x-ray microscopy is presented as a collection of modalities that allows to zoom into a mm-sized sample to acquire 3D maps of any embedded region and at essentially all relevant length scales. For coarse mapping of grains, their orientations and average stress state diffraction based tomography methods can sample thousands of grains with a resolution of 2 µm. At the 100 nm scale, domains and dislocations and their associated strain fields can be visualised by diffraction microscopy. Similar to dark field electron microscopy, diffraction and imaging can be combined in several ways. For the ultimate resolution, a bulk version of coherent diffraction imaging is introduced. Hard x-ray microscopy is optimised for acquisition of 3D movies: directly visualising the structural changes during nucleation and growth, deformation or damage. The state of art is provided along with examples of use. I discuss how hard x-ray microscopy studies can enable the formulation and validation of improved multiscale models that account for the entire heterogeneity of materials.