Thixomolding

Thixomolding is a commercial SSM process for injection molding magnesium alloys (Decker and LeBeau, 2008). As shown in Fig. 7, the process consists of introducing magnesium alloy feedstock in the form of metal granules at room temperature into a heated barrel and screw of a modified injection molding machine, and then raising the temperature of the material to a semi-solid region under high shear rate mixing. The semi-solid slurry, consisting of nearly spherical solid particles suspended in a liquid matrix, is then injected into a preheated metal mold to make a net shape part. Similar to vacuum die casting, this process results in less porosity and improved fatigue strength over conventional die casting.

The thin wall capability (0.5–1 mm) and the similarity with plastic injection molding process have resulted in successful applications of magnesium Thxiomolding in computer and electronics industries (casing applications for cell phones, cameras and computers).