Morphological Variation of Fe/Cr-Rich Intermetallic Phase in Recycled Al-Si Alloy as a Function of Solidification Rate: Time-Resolved Radiography

Effects of Cr addition on morphology of β-Al5FeSi phase formed in recycled aluminum alloy were studied as a function of cooling rate by technology of time-resolved radiography. The Cr addition to iron-contaminated recycled alloys modified the needle-like β-Al5FeSi into faceted dendritic α-AlFeCrSi phase in condition of conventional casting. Time-resolved radiography of the formation of α-AlFeCrSi revealed the transition of its morphology from polyhedron at about 10K/min of cooling rate to equiaxed dendrite of faceted arms at about 50K/min. of cooling rate.