Strength of Hycon 3 HP Be-Cu and other copper alloys from 20°C to 200°C

To be suitable for high-performance water-cooled magnets a conductor must have an excellent combination of electrical conductivity and tensile strength at moderately elevated temperatures. We have measured the 0.2% yield and ultimate tensile strengths, elongation and modulus of five copper alloys, in the form of heavily cold-worked strip 0.4 mm to 1.2 mm thick, at temperatures up to 200°C. The alloys are Hycon 3 HP Be-Cu (UNS alloy C17510), a 24% silver-copper being developed by NRIM (Tsukuba, Japan), Glidcop, Zr-Cu and electrolytic tough pitch copper. Be-Cu, Zr-Cu and Ag-Cu all retained strength very well. Be-Cu decreased in U.T.S. only 10% from room temperature to 200°C., Zr-Cu, 15%. For Ag-Cu the decrease was 10% from 20°C to 150°C, and another 10% during the next 50°C. Glidcop weakened 20% by 150°C. So did ETP copper, whose strength then plummeted another 50% by 200°C. Except for Ag-Cu, with its filamentary microstructure, all alloys were isotropic within about 5%. The anisotropy of Ag-Cu was about 12%, with the transverse direction being the stronger