Tailoring the microstructure and suppressing the β-AlFeSi intermetallic formation in 319 aluminum alloy through spray forming

Iron has very low solubility in aluminum, leading to the formation of Fe-rich intermetallic phases, such as β-AlFeSi. This phase forms with a platelet-like morphology that is detrimental to the mechanical properties of the alloy. It is well known that by applying high cooling rates or by adding manganese to the alloy it is possible to stabilize the α-AlFeSi or α-Al(Fe,Mn)Si intermetallic phase instead of the more detrimental β-AlFeSi. Spray forming is an advanced casting process that has been described as a potential technique to suppress β-AlFeSi formation. This work investigated the effect of different processing parameters on the microstructure evolution of spray-formed aluminum 319 alloy, mainly regarding the formation of α and β intermetallic phases. Results showed that the suppression of the β-AlFeSi strongly depends on the processing conditions and can be explained by the solidification mechanism prevailing in spray forming.