9612497 Ilegbusi Processing of materials in the semi-solid state has become a potentially attractive means of producing near net-shape parts. It is often achieved by controlling the microstructure from segregation prone alloys. However, there still exists a lack of understanding of the rheology and flow characteristics of the semi-solid state. The slurries often exhibit fractionation at mold extension and narrow sections. This phenomenon contributes to inhomogeneity of constitutive response and consequently produces unacceptable differential solidification and non-uniform mechanical properties in the solidified product. The research project addresses these issues by developing models to study the non-isothermal constitutive relationship for semi-solid slurries. Two test materials will be investigated: a tin-lead alloy and an aluminum-copper alloy. These materials will be studied both in the absence and presence of externally-imposed particulates of silicon carbide and aluminum oxide. A parallel experiment will be carried out to study the mold-filling characteristics under a range of operating conditions. This project has a balance between theory and experiment and could have a practical impact to the near-net shape engineering in manufacturing.
