Effect of semi-solid forming on the microstructure and mechanical properties of the iron containing Al–Si alloys

Iron is the most common impurity in aluminum casting alloys. The iron-bearing intermetallic compounds have the detrimental effects on the mechanical properties of the alloys. The aim of this research is to study the effects of plastic deformation and semi-solid forming on the morphology and distribution of the iron-bearing intermetallics and the microstructure and mechanical properties of the Al–Si alloys. Different amounts of iron and manganese were introduced into the A380 aluminum casting alloys. The alloys were processed through plastic deformation, recrystallisation and partial melting (RAP), and thixoforming. The microstructure and mechanical properties of the thixoformed alloys were investigated. The results showed that the RAP and thixoforming processes promote the formation of the very fine and well-distributed α-Al15(FeMn)3Si2 compounds in the aluminum matrix. The yield and tensile strength as well as elongation of the alloys have been increased considerably by semi-solid forming compared with the as-cast condition.

► Different amounts of iron and manganese were introduced into the A380 aluminum casting alloys.
► The alloys were processed through plastic deformation, recrystallisation and partial melting (RAP), and thixoforming.
► The RAP and thixoforming processes promote the formation of the very fine and well-distributed α-Al15(FeMn)3Si2 compounds in the aluminum matrix.
► The yield and tensile strength as well as elongation of the alloys have been increased considerably by semi-solid forming compared with the as-cast condition.