Laboratory three-dimensional X-ray micro-beam Laue diffraction.

The development of 3D non-destructive X-ray characterization techniques in home laboratories is essential for enabling many more researchers to perform 3D characterization daily, overcoming the limitations imposed by competitive and scarce access to synchrotron facilities. Recent efforts have focused on techniques such as laboratory diffraction contrast tomography (LabDCT). LabDCT allows 3D characterization of recrystallized grains with sizes larger than 15-20 µm, offering a boundary resolution of approximately 5 µm using commercial X-ray computed tomography (CT) systems. To enhance the capa-bil-ities of laboratory instruments, we have developed a new laboratory-based 3D X-ray micro-beam diffraction (Lab-3DµXRD) technique. Lab-3DµXRD combines the use of a focused polychromatic beam with a scanning-tomographic data acquisition routine to enable depth-resolved crystallographic orientation characterization. This work presents the first realization of Lab-3DµXRD, including hardware development through the integration of a newly developed Pt-coated twin paraboloidal capillary X-ray focusing optics into a conventional X-ray micro-computed tomography (µCT) system, as well as the development of data acquisition and processing software. The results are validated through comparisons with LabDCT and synchrotron phase contrast tomography. The findings clearly demonstrate the feasibility of Lab-3DµXRD, particularly in detecting smaller grains and providing intragranular information. Finally, we discuss future directions for developing Lab-3DµXRD into a versatile tool for studying materials with smaller grain sizes and high defect densities, including the potential of combining it with LabDCT and µCT for multiscale and multimodal microstructural characterization.