Preparation method for preparing Al-Mg-Si-O intermediate alloy in situ through melt method

The invention discloses a preparation method for preparing an Al-Mg-Si-O intermediate alloy in situ through a melt method. The preparation method comprises the following steps: melting pure aluminum into molten aluminum, and stirring and removing dross on the surface of the molten aluminum; sequentially adding Mg or an Al-Mg alloy and silicon dioxide powder into the molten aluminum and stirring the materials; continuously carrying out heating and smelting, carrying out in-situ heat preservation reaction, and stirring to obtain intermediate alloy melt; refining the intermediate alloy melt, removing the dross, and standing to obtain intermediate alloy liquid; cooling the intermediate alloy liquid and casting the intermediate alloy liquid into an alloy ingot; and obtaining the Al-Mg-Si-O intermediate alloy. The intermediate alloy containing MgAl2O4 and Mg2Si phases is prepared through the melt method, is used as an alterant of an aluminum alloy, and has the characteristics of safety in operation, environmental f