An Innovative Fabrication Concept for Niobium-Tin Superconducting Wire

60275 Preliminary designs for the next generation of high energy physics colliders will require much higher magnetic field levels for successful operation. Currently available superconducting materials are either unable to reach these levels (NbTi) or they are much too expensive (Nb3Sn, Nb3Al and HiTcSC). This project addresses the design and manufacture of Nb3Sn superconducting wire that holds promise for both better performance (3000 A/mm2 at 4.2K and 12T) and lower cost ($1.50/kA-m at 4.2K and 12T). The proposed architecture is a hybrid that includes features from both the Modified Jelly Roll (MJR) and Tin Infiltrated Niobium Sponge (TINS) methods. The niobium will be in the form of an expanded sheet, like the MJR, but the tin will be distributed uniformly across the cross-section, like TINS. This approach substantially increases the amount of niobium in the non-copper cross-section and will increase the amount of Nb3Sn in the completed conductor, which leads to an increased Jc value. Phase I demonstrated that the Modified Jelly Roll/Distributed Tin (MJR/DT) structure can be extruded, under certain circumstances. Preliminary design considerations for hydrostatic extrusion and drawing facilities were developed. Phase II will determine the best approach for mechanically stabilizing the structures so they can be successfully processed to wire. In addition, the existing hydrostatic extrusion facilities will be modified to include small half-angle dies, so the range of sound flow can be increased. Wire samples will be heat treated to find the optimum processing steps. Using these results, a series of billets will be processed, and approximately 1,000 foot samples will be produced. Commercial Applications and Other Benefits as described by the awardee: A high performance, relatively low cost A-15 material would be an enabling development for the use of high magnetic fields. Applications include high energy physics and energy storage. Also, the manufacturing techniques developed in this project could provide new methods for processing difficult materials