4D microstructural evolution in a heavily deformed ferritic alloy: a new perspective in recrystallisation studies

We present a multiscale study on the recovery and recrystallisation of a heavily deformed (85% reduction in size) Fe–Si–Sn alloy using a combination of dark field X-ray microscopy (DFXM), synchrotron X-ray diffraction (SXRD) and electron backscatter diffraction (EBSD). By utilizing DFXM, we focus on a grain within the high stored energy (HSE) regions, and track it through consecutive isothermal annealing steps. The intra-granular structure of the as-deformed grain reveals deformation bands separated by ≈3–5° misorientation. During the early stages of annealing, cells with 2–5° misorientation form while new nuclei appear. The recrystallized grains nucleate near prior grain boundaries, having a typical internal angular spread of <0.05°. The SXRD results suggest no significant macroscopic texture change after annealing for 1400s at 610 °C in the HSE regions. All results indicate that higher misorientation zones such as grain boundaries or junction points of deformation bands are preferential nucleation regions.