Failure Analysis of Al1060 Sheets under Double-Sided Pressure Deformation Conditions

摘要

The viscous pressure bulge (VPB) testes of the aluminum Al1060 sheet were carried out with stainless steel overlapped outside without lubricant. The influence of the compressive normal stress on the failure behavior of aluminum sheet was investigated by scanning electron microscope observations. The results indicate that the forming limit of overlapped aluminum sheet is increased significantly compared with the single aluminum sheet. Fractography shows that the void growth and conjunction in the thickness direction is restrained by normal pressure and the fracture mode of overlapped sheet transits from the dimple fracture to shear fracture due to the reduction of stress triaxiality.