Development of a High Field NbTi Superconductor Using an Approach Combining Artificial Flux Pinning With Conventional Thermomechanical Processing

173 Development of a High Field NbTi Superconductor Using an Approach Combining Artificial Flux Pinning With Conventional Thermomechanical Processing--Supercon, Inc., 830 Boston Turnpike, Shrewsbury, MA 01545-3301; (508) 842-0174 Dr. Dingan Yu, Principal Investigator Ms. Elaine Drew, Business Official DOE Grant No. DE-FG02-97ER82486 Amount: $74,993 Superconductors with higher critical current densities at high magnetic fields are in constant demand in applications such as particle accelerators, plasma physics experiments and nuclear magnetic resonance magnets. So far, most of NbTi-based superconductors fabricated using Artificial Pinning Center techniques are not superior to the conventional Nb46.5 Ti alloy with respect to their high field performances. This project aims at the development of a new high-field NbTi superconductor using an approach combining the Artificial Pinning Center technique with conventional thermomechanical processing for NbTi alloy superconductors. It is expected that the high-field critical current densities of this new superconductor will be enhanced when compared to that of a conventional Nb46.5Ti superconductor. This is based on the additional flux pinning centers that are available and due to the overall composition that is similar to Nb44wt.%Ti alloy, which has the maximum upper critical magnetic fields in the NbTi binary alloy system. In Phase I of this project, a single core superconducting wire using this new technique will be fabricated and tested against a conventional Nb46.5Ti superconductor to demonstrate the feasibility of this new approach. Multiple intermediate heat treatments similar to those for Nb46.5Ti superconducting wires will be employed during wire processing to promote alpha-Ti precipitates. In addition to these ribbon-shaped alpha-Ti precipitates, the co-processed Nb inclusions will also act as flux pinning centers to support supercurrents in the superconductor. In Phase II of this project, the overall composition and processing parameters of the new superconductor will be optimized. In addition, scale-up of fabrication will be performed. Commercial Application and Other Benefits as described by the awardee: The target application for this new superconducting wire is in building high-field superconducting magnets for use in high energy particle accelerators such as the high gradient quadrupole magnets used in the interaction regions of Fermilab accelerator and the Large Hadron Collider at the CERN laboratory in Geneva, as well as in fusion and nuclear resonance magnets.