The Influence of Alloy Composition on the Microstructure, Tensile Ductility and Formability of 6xxx Alloys

Abstract

In this study, the effect of Si and Mg content on the microstructure, tensile ductility, and formability of naturally aged Al-Mg-Si alloys of the 6xxx series has been investigated using optical microscopy, scanning electron microscopy, tensile testing and forming limit diagram tests. The results show that by raising the Si content the work hardening capacity and the strain rate sensitivity of the alloys can be enhanced. Increase in the Si concentration also promotes a more homogeneous distribution of dispersoids. Collectively, these effects act to improve the tensile ductility and formability of these sheet materials. By contrast, an increase of the Mg content has little influence on the tensile ductility and formability due to reduced strain rate sensitivity and a more heterogeneous distribution of dispersoids.