Analysis of mold flow and microstructures of die casting in Al alloy/SiC(p) composites

The report involves a study of the microstructure of tensile, impact and th ree-point bending samples of aluminum alloy/SiC(p) composites produced by d ie casting. The results show that in impact samples, 80 mu m SiC particulat es cluster along the left and right edges of the section vertical plane wit h the notch plane, and near the notch. In tensile and three-point bending s amples, they were distributed uniformly in the matrix. Furthermore, porosit ies occurred near the notch in the impact samples. The 80 mu m SIC particul ates will undergo settling in the shot biscuit. There exist are and irregul ar shapes in the clustering section of the particulate. The dendrite arm sp acing (DAS) is larger in this section. From the shot biscuit to the bending section of the sprue; the quantity of SIC particulate is less. The SiC par ticulate is clustered in the protrusive region where the injector pins are situated. We can decrease the porosity of die casting samples effectively b y designing the overflow well in a wave shape. We can prevent the melt from adhering to the surface of the mold cavity, thermal cracking on the surfac e of die casting samples and wear on plungers using electroless nickel plat ing on the SiC particulate. (C) 1999 Kluwer Academic Publishers.