High-Strength Cu–Ta–W Composite

Abstract

High-strength copper conductor composites have been used in pulse magnet applications and as internal reinforcement in superconductor wires. The required property is high strength while maintaining high conductivity. Heavily worked pure copper has a strength of 450-500 MPa. Increasing the strength of copper by alloying additions without affecting the conductivity drastically is a significant challenge. Mixing pure copper with a higher modulus, higher strength tantalum alloys is an option to meet the challenge. This work reports on the use of a tantalum-tungsten alloy to strengthen high-purity copper through a multi-filament approach. The tantalum tungsten has a high modulus and very low solubility in copper. A composite wire containing 133 filaments of Ta-W (25% by volume) has a conductivity of 80% International Annealed Copper Standard and ultimate tensile strength of over 650 MPa with a modulus over 140 GPa. The wire has good ductility and toughness. These results are comparable or better than current options, and the potential to improve this product is explored.