Effect of strain path on deformation texture of superconducting niobium sheet

The texture of high purity superconducting niobium sheets plays an important role in the physical and mechanical properties of high purity niobium sheet that are important for manufacturing of superconducting accelerator cavities. In a particular batch of sheet metal, orientation imaging microscopy showed an inhomogeneous texture from the surface to the mid-thickness of the sheet consisting a gamma fiber, {111}), cube fiber, {100}), and also some components on the alpha fiber, {hkl}<110>. With uniaxial deformation, peaks on the {uvw}<111> gamma fiber evolve differently depending on the in-plane direction of deformation, and the position in the sample (surface vs. center). Applying a different strain path such as balanced biaxial bulging, leads to development of rotated Goss, {110}<110> components in the texture of the deformed niobium. These results show that the texture of niobium is very sensitive to the deformation and strain path.