The study of refinement for primary silicon in Cu-50Â wt.%Si alloys

The refinement for the primary silicon in Cu-50 wt.%Si by pure Al and Cu-P master alloy was investigated in this work. The experimental results reveal that, similar to hypereutectic Al-Si alloys, AlP particles can also act as the heterogeneous nucleating sites for primary silicon in Cu-Si alloys, and the primary Si can also be refined with the AlP particles. Another discovery is that pure Al can refine primary Si in Cu-50 wt.%Si alloys since Al4Cu9 can form a loop around the primary Si. To get round and small primary Si particle, it is important for AlP and surplus Al coexisting in the melt, and the addition level of Al and P should be Al:P > 1.