Forming limit diagram with anisotropy considering of Ti-6Al-4V sheets and prediction of ductile fracture by experiment and FEA

Abstract

Ti-6Al-4V titanium alloy sheets were focused on to clarify the forming limit curve. At first, finite element analysis (FEA) was utilized to calculate the suitable dimension of the sheet to the extent heretofore provided in ISO 12004 and to determine the forming limit curve. The punch dome test was carried out to obtain the forming limit with anisotropy considering of the Ti-6Al-4V sheets by using the suitable workpiece dimension. Additionally, the method to prevent fracture occurrence during the punch dome test was suggested, and the effect of the developed method on the fracture occurrence at the bead portion was demonstrated during punch dome test for determination of forming limit curve. Hence, the forming limit curve considering the anisotropy of the Ti-6Al-4V sheets was obtained by using the developed method to prevent the fracture at the bead portion. In addition, FEA of the dome punch test considering the anisotropy was performed to confirm the effects of the developed method on the fracture at the bead portion and the anisotropy of Ti-6Al-4V on the forming limit, in addition, to predict the forming limit by using ductile fracture criteria. As the results, the database of the forming limit curve of the Ti-6Al-4V sheets was constructed by an experiment and FEA.