Effect of Casting Condition in Semi-Solid Aluminum Alloy Injection Process on Distribution of Defects and Density

Semi-solid process is expected as near net shape method with high quality. In this study, the semi-solid aluminum slurry was injected into a metallic mold with spiral shape cavity via some gates of several thicknesses. The effects of injection speed and gate thickness on the distribution of casting defects and density were investigated. Most of the casting defects appeared at the center of the specimen. The casting defects were generated most frequently on the tip of the spiral specimen. The amount of casting defects was decreased by semi-solid injection process than general high pressure die casting. The density of specimen made by the semi-solid injection process was approximately the same as high pressure die cast at near the gate, and increased in the other area.