Prototype castings of aluminum - Fly ash composites for industrial applications

This paper summarizes the work in progress at University of Wisconsin-Milwaukee on incorporating fly ash in aluminum castings to decrease the cost and weight of selected industrial components. Aluminum alloy (A356) - fly ash composite ingots and selected parts were successfully cast in sand and permanent molds using conventional foundry techniques from large scale heat (400 pounds). The sand and permanent mold castings including intake manifolds and brake drums show adequate castability of the melts containing fly ash particles. The results of microstructure analysis and property examination indicate that the strength of casting is significantly influenced by the amount and distribution of fly ash particle in the castings. The room temperature tensile strength of composite castings containing less than 8 vol% fly ash is similar to that of the base alloy and then decreases with further increase in fly ash contents. The tensile strength measured at 600 F is about 7 to 10 ksi for the composite castings containing 2 to 12 vol% fly ash which is higher than that of the base alloy (4 ksi). The ingots made by permanent mold castings have been successfully remelted and squeeze cast into motor mounts. The properties of squeeze cast aluminium - fly ash composites are better than sand and permanent mold cast material. The results indicate that, incorporation of fly ash in aluminum castings can represent an important new use of fly ash.