HIGH-STRENGTH AND HIGH-CONDUCTIVITY CU-AG ALLOY SHEETS - NEW PROMISING CONDUCTOR FOR HIGH-FIELD BITTER COILS

A sheet-conductor fabrication method has been developed for Cu-Ag alloys containing 6-24 mass% Ag. Both the strength and the conductivity of the sheet were improved remarkably by the repetition of heat treatment combined with cold working. The intermediate heat treatments were repeated 3 times at 400-450-degrees-C for 1-2 h at appropriate stages of cold-rolling. The optimized Cu-24 mass% Ag alloy sheet with a 96% reduction ratio showed a ultimate tensile strength of 1050 MPa and an electrical conductivity of 75% IACS at room temperature. Anisotropy in the strength with respect to the rolling direction was less than 10%, and no anisotropy in the electrical conductivity were observed. The sheets fabricated by this method are promising as conductors for high-field Bitter magnet coils.