Temperature-Dependent Constitutive Behavior and Fractionation of Semi-Solid Slurries

9612497 Ilegbusi 半固态材料加工已成为生产近净形零件的一种具有潜在吸引力的方法。 这通常是通过控制易偏析合金的微观结构来实现的。 然而，人们对半固态的流变学和流动特性仍然缺乏了解。 浆料经常在模具延伸和狭窄部分表现出分馏。 这种现象导致本构响应的不均匀性，从而在凝固产品中产生不可接受的差异凝固和不均匀的机械性能。 该研究项目通过开发模型来研究半固体浆料的非等温本构关系来解决这些问题。 将研究两种测试材料：锡铅合金和铝铜合金。 这些材料将在不存在和存在外部施加的碳化硅和氧化铝颗粒的情况下进行研究。 将进行平行实验来研究一系列操作条件下的模具填充特性。 该项目在理论和实验之间取得了平衡，可以对制造中的近净形状工程产生实际影响。

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.