Al 5083 disks of superplastic forming grade were gas-pressure formed into hemispheres and cones at constant forming pressures with and without back pressure. The forming operation was performed using an in-house designed and built biaxial forming apparatus. The temporal change of dome heights of the hemispheres and cones were measured for the different forming and back pressures applied. The flow stresses and strain rates developed at the top of the dome during the forming step were shown to closely follow the flow stress - strain rate relationship obtained from the strain rate change tests performed at the same temperature using uniaxial tensile samples. The forming process was modeled using a finite element code (NIKE2D) and preliminary results are presented.
展开▼
