Abstract:Nucleation of dendritic primary a(Al) phase with addition of element Ce and Sr in hypoeutectic Al-7%Si-Mg cast alloy was investigated by using differential scanning calorimetry (DSC) and scanning electron microscopy. DSC results were used to calculate the activation energy and nucleation work of primary a(Al) phase. The results show that the values of activation energy and nucleation work are decreased and the nucleation frequency is increased with the additions of Ce and Sr to the alloys. Moreover, the grain size of dendritic a(Al) phase is well refined, and the nucleation temperatures of primary a(Al) dendrites are decreased with the additions of Ce and Sr. The effects of elements Ce and Sr additions on kinetic nucleation of primary a(Al) phases were also discussed in hypoeutectic Al-7%Si-Mg cast alloy.

Key words: aluminium alloy; primary α dendrite; nucleation; grain refinement; activation energy; nucleation work; Ce; Sr