Nucleation and growth behavior of primary Al11Ce3 intermetallic compounds during solidification in a hypereutectic Al–Ce alloy

Abstract

In this study, the nucleation and growth mechanisms of Al₁₁Ce₃ intermetallic compounds (IMCs) in a hypereutectic Al–Ce alloy during solidification were investigated through synchrotron radiation X-ray real-time imaging. The results showed that Al₁₁Ce₃ IMCs nucleate and grow from the melt as the primary phase at the initial stage of solidification. Growth preferred orientations were observed in two opposite directions, resulting in an I-shaped growth pattern. Based on the minimum energy criterion, the morphology of Al₁₁Ce₃ IMCs displayed either hollow cubic tubes or grooves. The nucleation and growth rates of Al₁₁Ce₃ IMCs gradually decreased over time, owing to the variations in the Ce concentration in the melt and the undercooling. The nucleation and growth characteristics of Al₁₁Ce₃ IMCs can provide the theoretical basis for optimization on the performance of Al–Ce alloys.