The introduction of three new advanced acquisition strategies for lab-based diffraction contrast tomography (LabDCT) – named Helical Phyllotaxis, Helical Phyllotaxis Raster, and Helical Phyllotaxis HART – enables grain mapping of longer, larger, as well as high-aspect ratio samples. The implementation of these advanced acquisition strategies combines a golden angle rotation with vertical and horizontal translations to perform a seamless data collection that has a uniform sample illumination both angularly and spatially. Reconstruction of the corresponding data is equally seamless, simultaneously using all data to reconstruct the full illuminated volume without the need for stitching of data subsets or sample subvolumes.
Next level of in-house 3D grain mapping
The advanced acquisition strategies take lab-based non-destructive 3D grain mapping to the next level of throughput, grain statistics and versatility. While the throughput warrants 4D studies of materials microstructural evolution, a representative sample volume is a prerequisite for successful model predictions, and the versatility enables studies of samples or components under more realistic in situ or in operando conditions. In addition, the Helical Phyllotaxis HART (high-aspect ratio tomography for plate-like samples) strategy enables investigations of a hitherto inaccessible class of sample geometries comprising industrially relevant materials like rolled metal sheets and electrical steels.