Effect of mechanical properties, microstructure and residual stress on the bending springback behavior of high-strength Al-Mg-Si-Cu alloy tubes

In this work, the bending behavior of high-strength Al-Mg-Si-Cu alloys and AA6061 under different artificial aging condition was investigated. The existing springback prediction formula is suitable for commercial AA6061 alloy, but not for high-strength Al-Mg-Si-Cu alloy. Subsequently, the microstructure, mechanical properties and residual stress of AA6061 and high-strength Al- Mg-Si-Cu alloys were investigated. The results show that the yield strength and residual stress play important roles on the springback of high-strength Al-Mg-Si-Cu alloy. In addition, a springback prediction formula based on residual tensile stress has been proposed, which makes the prediction accuracy higher than 96 %. This provides theoretical guidance and data support for the application of high-strength Al-Mg-Si-Cu alloys in lightweight automotive materials.