Refiner for aluminum alloy and preparation method

The invention provides a refiner for aluminum alloy and a preparation method. The refiner for the aluminum alloy comprises, by weight, the components of 4.5-5.5% of titanium, 0.2-0.4% of cerium, 0.6-1.8% of magnesium and the balance aluminum. The refining effects of two refiners of Al-5Ti and Al-5Ti-0.7Mg-0.3Ce on Ai-Si alloy are compared to find that the refining effect of the Al-5Ti-0.7Mg-0.3Ce is better than that of the Al-5Ti due to the fact that the size of Al3Ti in the Al-5Ti-0.7Mg-0.3Ce is obviously smaller than that of the Al-5Ti in the Al-5Ti-0.7Mg-0.3Ce, therefore, the quantity of heterogeneous nucleation is increased, and the refining effect is more obvious; in addition, an element Mg and rare earth elements are filled in the interface of an alpha-Al dendritic crystal and eutectic silicon, therefore, the growth of the alpha-Al dendritic crystal is prevented, the improvement of the refining effect is facilitated, and more remarkable, the improvement effect of the interaction effect of the element Mg and the rare earth elements for a refining structure is more obvious than that of a single rare earth element.