In-situ synchrotron X-ray radiography observation of primary Al2Cu intermetallic growth on fragments of aluminium oxide film

While using synchrotron X-ray radiography for studying ultrasonic melt processing, the growth of the primary Al2Cu intermetallic phase on fragments of aluminium oxide film during solidification of a hypereutectic Al-35% Cu alloy was observed in-situ and in real time with adequate spatial and temporal resolution. This provides the first direct evidence for the nucleation of a primary phase on oxide particles during solidification of real metallic alloys. Comparison of the primary Al2Cu intermetallics grown in the melt with and without fragments of aluminium oxide film reveals considerable refinement, which demonstrates that the enhanced nucleation of a primary phase on oxide particles promotes structure refinement