Effects of pre-deformation on microstructure evolution and hemming performance for Al-Mg-Si-Cu alloys

Abstract

The effects of pre-deformation on the microstructure evolution and hemming performance of Al-Mg-Si-Cu alloys were systematically investigated by Scanning Electron Microscope (SEM) and Electron Back-Scattered Diffraction (EBSD) characterizations. During the hemming process of Al-Mg-Si-Cu alloys, the formation of shear bands within grains is observed, leading to localized strain and the development of surface undulations. The shearing action within the slip zone results in the fragmentation of Fe-intermetallic particles, which in turn promotes the nucleation of microscopic pores in the surrounding matrix. The further expansion of the micropores leads to the formation of microcracks. Cube-oriented grains inhibit the expansion of macroscopic shear bands caused by strain localization during hemming. The pre-deformation before hemming introduces large number of dislocations in the Al-Mg-Si-Cu alloy and reduces the composition of the Cube texture, which reduces the hemming performance of the alloy.

Keywords

• Al-Mg-Si-Cu alloy
• Precipitation
• Microstructure
• Hemming performance
• Strength