Development of Hemmable Al-Mg-Si Automotive Sheet Alloys

Hemming is commonly used to join exterior automotive body panels to interior body panels. This procedure requires the sheet to bend 180° without showing cracks or surface cosmetic defects. However, current commercial Al-Mg-Si alloys often fail during this deformation, especially after natural ageing. This study provides insights on how cosmetic failures are formed and could they be prevented by improved alloy design.