Heterogeneous nucleation in Mg-Zr alloy under die casting condition

Heterogeneous nucleation behaviour was studied in die casting Mg-Zr alloy. It was found that up to 48.78% Zr particles could be used as nuclei and the nucleation occurred on curved and faceted interfaces. It meant that the size effect of nuclei in Mg-Zr alloy was insignificant, and this nucleation behaviour was independent on any crystallography orientation. Therefore, a large range of Zr nuclei could be activated simultaneously under the large undercooling through the delayed recalescence resulting in a very high nucleation efficiency.