Tailoring the microstructure of recycled 319 aluminum alloy aiming at high ductility

Abstract

Iron has low solubility in solid aluminum and for this reason it can lead to the formation of Fe-rich intermetallic phases (such as β-AlFeSi in Al-Si cast alloys) severely impairing the ductility of the material. Spray forming is an advanced casting process that has been described as a potential technique to highly decrease the β-AlFeSi formation, consequently increasing the ductility. This paper aims to study the effect of pouring and tundish temperature in the microstructure of 319 aluminum alloy with high iron content processed by spray forming. Spray formed ingots and overspray particles were analyzed for two different processing conditions. In order to evaluate the mechanical properties, the spray formed deposits were mechanically conformed by hot swaging. Results showed that the decrease in the β-AlFeSi content strongly depends on the processing conditions. Spray formed deposits processed by hot swaging presented high ductility, allowing a wide range of possibilities to apply casting alloys with high impurity content to more valuable applications beyond the casting industry, therefore decreasing the needs for using primary alloys and contributing to the environment. Keywords: Spray forming, Aluminum upcycling, Solidification, AlFeSi intermetallic, 319 aluminum alloy