Development of large area and high-strength CuAg alloy plates for high field Bitter coils

A poly Bitter coil is desired as the resistive coil of a hybrid magnet from the viewpoint of easy fabrication. Recently, high silver content and high- strength CuAg alloy is developed. This alloy, however, is so hard. It is di fficult to make thin and very flat plates of the CuAg alloy with large area . We succeeded in fabricating 26 mass%Ag-Cu plates with the thickness of 0. 8 mm and an area of 340 mm x 340 mm square by using a special rolling proce ss and heat treatment. The plates have a maximum 0.2% proof stress greater than 670 MPa and a mean electrical conductivity greater than 78%IACS at roo m temperature. The magnetoresistance of CuAg alloys were measured up to 15 T magnetic fields. The increase in the resisitivity was very small.