X-Ray Diffraction Contrast Tomography in micro-CT Lab Source Systems

摘要

In this work we have developed an efficient projector for laboratory based, polychromatic cone beam diffraction imaging. Using this projector, the three-dimensional shape of grains with negligible intra-granular orientation gradient can be reconstructed using iterative, algebraic reconstruction techniques (e.g. SIRT). The reconstructions show a clear improvement compared to the previously used processing route, based on a regular cone beam projector and affine transformation of the projection images. With further improvement of polycrystalline indexing algorithms and with extension to a 6D reconstruction framework, we anticipate LabDCT to become a true alternative to established synchrotron techniques. The combination of absorption (detection of damage, second phases, porosity, plastic strain via 3D digital volume correlation techniques) and diffraction imaging (crystal shape and orientation, elastic strain) on the same instrument will provide unique possibilities for (interrupted) in-situ characterization of dynamic processes in the bulk of polycrystalline materials (e.g. grain coarsening during heat treatment, plastic deformation and damage mechanisms, etc.).