Mechanically reinforced {110}<110> textured Ag/Ni-alloys composite substrates for low-cost coated conductors

摘要

New, reinforced {110} <110> textured Ag/Ni-alloys composite ribbons were developed as possible substrates for coated conductors without any buffer layer. The texture quality and tensile strength were investigated. A new technique to bond the Ag and Ni or alloy layers through a Cu foil was presented. The Ag/Ni-alloys composite ribbons were fabricated by choosing proper sintering processing to bond the different layers followed by cold rolling and recrys-tallization. A thin Cu foil was intercalated between the initial Ag and Ni or alloy pieces to get a tough bond. A unique and stable {110}<110> annealing texture was obtained in 300 μm thick Ag/Ni composite ribbon after annealing. X-ray ODF analysis and EBSD measurements in the top Ag layer showed distribution of misorientation angles around 10-15°. A {11 0}<110> texture was also found in ribbons as thin as 50 μm, which cannot be obtained with pure Ag ribbons. A pronounced reduction of Ag amount was obtained in 60 μm thick Ag/NiCrV ribbons, with a textured Ag top layer being as thin as 7 μm. The amount of Ag was decreased by 75% compared to pure Ag ribbons of the same thickness. A strong enhancement of the mechanical properties was observed. The yield strength σ_(0.2) at 77 K was 220 MPa for Ag/NiCrV ribbons, i.e. considerably higher than the 30 MPa for pure Ag ribbons.