On flow stress anisotropy in Ti-6Al-4V alloy sheet during superplastic deformation

The anisotropy of flow stress in a cold rolled sheet of Ti-6Al-4V alloy has been observed during superplastic deformation at 850 C. At this temperature, the alloy has duplex microstructure with almost equiaxed grains of the alpha and beta phases. The maximum value of flow stress has been established for the rolling direction and minimum—for the transverse one. Also, the anisotropy of crystallographic texture weakening in the alpha phase has been observed. However, it has been demonstrated that texture in the alpha phase cannot be responsible for the observed anisotropic behavior. Texture in the beta phase is the suggested reason for the flow-stress anisotropy during superplastic deformation.