Control of texture in Ag and Ag-alloy substrates for superconducting tapes

The use of a biaxially textured silver tape as a substrate for high tempera ture superconductor (HTS) phases is one possible route towards the fabricat ion of high-Je superconducting tape. Using a cold-rolling and annealing pro cess we have reproducibly fabricated {110}(110) textured silver which is st able up to 900 degrees C. We have found that there are two critical process requirements for the formation of this texture; a low oxygen content in th e material prior to deformation, and a cold-rolling thickness reduction of less than 97%. To overcome the problems associated with the poor mechanical strength of pure silver, texture development in Ag-Mg and Ag-Hf alloys wit h improved mechanical properties has been studied. Heat treatments in a red ucing atmosphere allow the {110}(110) annealing texture to be obtained in A g-0.1 wt%Mg. The recrystallization behaviour of a Ag-Pd alloy with an incre ased stacking fault energy was also investigated and a partial cube texture was obtained in this material. Using orientation distribution function (OD F) analysis we have shown that minor variations in the deformation texture of both pure silver and Ag-based alloys can lead to significant differences in the recrystallization textures obtained.