Fig. 4: Projection pDFXM maps showing subgrain structure and orientation mapping in highly deformed ferritic Fe-3%Si.

Projection orientation maps were obtained around the (110) Bragg peak using dark-field X-ray microscopy (DFXM) through the objective lenses at a photon energy of 19 keV in a cold-rolled ferritic Fe-3%Si sample with 50% thickness reduction, indicative of high plastic deformation and elevated defect density. a Integrated intensity map, representing the amplitude (log scale) of Gaussian fits to the rocking curve⁵⁵, i.e., tilting goniometer angle ϕ around the diffraction vector and collecting images at each point, highlights variations in diffracted signal strength. b The average ϕ orientation (peak position) map reveals local lattice rotations associated with deformation-induced substructure, with the cell structure overlaid using kernel average misorientation (KAM) filters to highlight cell boundaries. c Full-width at half-maximum (FWHM) of the rocking curve, i.e., local peak broadening, showing dislocation cell boundaries as regions with increased FWHM and reduced integrated intensity, indicative of strain localization and subgrain formation.