Microstructures and Tensile Fracture Behavior of 2219 Wrought Al–Cu Alloys with Different Impurity of Fe

The Fe-rich intermetallic phases have a broadly detrimental effect on the mechanical properties of Al–Cu alloy. In this paper, the continuous evolution of Fe-rich intermetallics and their effects on mechanical properties, especially the tensile fracture behavior of 2219 wrought Al–Cu alloys as a function of Fe content against different processing approaches (i.e., as-cast, homogenization, multidirectional forging, and solution-peak aging treatment) were investigated using optical microscopy, scanning electron microscopy, and tensile tests. The results indicated that needle-like Al₇Cu₂Fe or Al₇Cu₂(Fe, Mn) intermetallics mainly presented in the final microstructures of all alloys with various Fe contents. The size and number of Al₇Cu₂Fe/Al₇Cu₂(Fe, Mn) intermetallics increased with the increase of Fe content. The increase of Fe content had little influence on the ultimate tensile strength and yield strength, while obvious deterioration in the elongation, because fracture initiators mainly occurred at the Al₇Cu₂Fe/Al₇Cu₂(Fe, Mn) particles or particles–matrix interface. Therefore, the 2219 Al–Cu alloy with 0.2 wt.% Fe content presented relatively low tensile ductility. The tensile fracture mechanism has been discussed in detail.