Investigation of orientation gradients around a hard Laves particle in a warm-rolled Fe3Al-based alloy using a 3D EBSD-FIB technique

We present a study of the microstructure around a hard Laves particle in a warm-rolled intermetallic Fe3Al-based alloy. The experiments are conducted using a system for three-dimensional orientation microscopy (3D electron backscattering diffraction, EBSD). The approach is realized by a combination of a focused ion beam (FIB) unit for serial sectioning with high-resolution field emission scanning electron microscopy with EBSD. We observe the formation of steep 3D orientation gradients in the Fe3Al matrix around the rigid precipitate which entail in part particle-stimulated nucleation events in the immediate vicinity of the particle. The orientation gradients assume a characteristic pattern around the particle in the transverse plane while revealing an elongated tubular morphology in the rolling direction. However, they do not reveal a characteristic common rotation axis. Recovered areas in the matrix appear both in the transverse and rolling directions around the particle. The work demonstrates that the new 3D EBSD-FIB technique provides a new level of microstructure information that cannot be achieved by conventional 2D-EBSD analysis.