The largest application field of magnesium is the addition of elements to aluminum alloys. The main purpose is to improve various performance indicators of aluminum alloy die castings, especially the corrosion resistance. According to experts, aluminum-magnesium alloy die-casting parts are both light and hard, have good corrosion resistance, and are easy to weld and other surface treatments. They are important materials for manufacturing aircraft, rockets, speedboats, vehicles, etc. According to statistics, more than 45% of the magnesium used in the United States is used as an additive element of aluminum alloys every year, and magnesium is also used in a large amount as an additive element of aluminum alloys in China. In addition, magnesium is added to zinc die-cast alloys to increase their strength and improve dimensional stability.