Casting Surface of AZ91 Alloy and Its Reaction with Sand Mold

Due to its light weight and abundance as a resource, the utilization of magnesium is increasing. AZ91 alloy is the most common cast magnesium alloy and is widely used as die-casting material. AZ91 is also used for sand mold casting. In sand mold casting, reaction with mold sand is expected because magnesium is a very reactive element. This study investigated the surface condition of AZ91 castings using sand mold.Higher pouring temperature promoted the reaction with silica sand, and the surface of castings became rough. Reacting with mold sand, Mg2Si and Mg and Al complex oxides were precipitated near the casting surface.