Effect of Rare Earth Ce on the Growth of Primary Al<sub>13</sub>Fe<sub>4</sub> Phase in Al-5Fe Alloy

Abstract

The solid-liquid mixture of Al-5Fe-xRE alloy is "frozen" through rapid cooling technology to prepare solid samples (the weight percentage of Rare Earth Ce added in x: 0%, 0.9%, and 5%). The effect of Ce on the growth of primary Al13Fe4 phase is studied by means of differential scanning calorimetry (DSC) and field emission transmission electron microscopy (TEM).The results show that with the increase in the amount of Ce in the alloy, the transition temperature of the primary Al13Fe4 phase increases. The addition of Ce changes the crystallization process of the primary phase. When Al-5Fe-xRE alloy is rapidly cooled at 690°C, the primary phase interface of Al-5Fe-5Ce alloy has more Rare Earth enrichment than that of Al-5Fe-0.9Ce alloy. However, the primary phase of Al-5Fe-5Ce alloy is still relatively coarse. Obviously, excessive Ce does not play a role in modification, so the enrichment of Ce at the interface may not be the main reason for refining the primary iron-rich phase When the Al-5Fe-5Ce alloy is rapidly cooled at 750°C and 690°C, respectively, the Ce at the interface tends to increase. The enrichment area of Ce forms a "film" at the interface of the primary phase, and then it transform into Al8CeFe2 phase after solidification. The interface structure of the primary and Al8CeFe2 is semi-coherent.