Growth Dynamics of Faceted Al13Fe4 intermetallic Revealed by High-speed Synchrotron X-ray Quantification

High-speed synchrotron tomography was used to investigate the nucleation and growth dynamics of Al13Fe4 intermetallic during solidification of an Al-5wt%Fe alloy, providing new insights into its formation process. The majority of Al13Fe4 intermetallics nucleated near the surface oxide of the specimen and a few nucleated at Al13Fe4 phase. Al13Fe4 crystals grew into a variety of shapes, including plate-like, hexagonal tabular, stair-like and V-shaped, which can be attributed to the crystal structure of this compound and its susceptibility to twinning. Hole-like defects filled with aluminium melt were observed within the intermetallics. Orentied particle attachement mechanism was proposed to explain the formation of the Al13Fe4 intermetialic, which needs further experiments and simulation to confirm.