Modification effect of Ni–38 wt.%Si on Al–12 wt.%Si alloy

Modification effect of Ni–38 wt.%Si on the Al–12 wt.%Si alloy has been studied by differential scanning calorimeter, torsional oscillation viscometer and liquid X-ray diffraction experiments. It is found that there is a modification effect of Ni–38 wt.%Si on Al–12 wt.%Si alloy, i.e. primary Si can precipitate in the microstructure of Al–12 wt.%Si alloy when Ni and Si added in the form of Ni–38 wt.%Si, but not separately. Ni–38 wt.%Si alloy brings “genetic materials” into the Al–Si melt, which makes the melt to form more ordering structure, promotes the primary Si precipitated. Moreover, the addition of Ni–38 wt.%Si, which decreases the solidification supercooling degree of Al–12 wt.%Si alloy, is identical to the effect of heterogeneous nuclei.