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

Daofen Xu,Chengfu Xu,Kanghua Chen,Changjun Zhu

doi:10.3390/met11010174

Daofen Xu, Chengfu Xu + Show 2 more

Open Access

https://doi.org/10.3390/met11010174

Copy DOI

Abstract

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.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
We investigated the continuous evolution of Fe-rich intermetallic particles in 2219 wrought Al–Cu alloys as a function of Fe content across casting, homogenization, multidirectional forging (MDF), and solution-peak aging treatment
As the Fe content increased to 0.10 wt.%, a new needle-like Al7 Cu2 Fe or

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The heat-treatable type 2xxx Al–Cu alloys have been widely used in transportation and aerospace industry owing to its high specific strength and good weldability. Such as the employment of 2219 Al–Cu alloy in fabricating propellant tank of large launch vehicle [1,2] and the utilization of 2519 Al–Cu alloy as structure component of armored vehicle [3]. It is well known that the solubility of impurity Fe in Al–Cu alloys is very poor

Methods

Discussion

Conclusion