Process and Cost Optimization of Aluminum Stabilized NbTi Superconducting WireAssessment of Cladding Technologies for Aluminum Stabilized NbTi Superconducting Wire

摘要

Recent advances in the development of the aluminum stabilized NbTi superconductorhave great potential for military and commercial applications such as mine sweeping and magnetic resonance imaging (MRI). Producing long, low-cost conductors requires either improving the current technology or developing new approaches to aluminum cladding and conductor forming processes. However, these cladding and forming processes should be coupled with concurrent product and process design based on material properties and simulation models. The Program Executive Office, Mine Warfare, tasked the National Center for Excellence in Metalworking Technology (NCEMT) to asses the current state-of-the-art in cladding technology for NbTi superconductors, based on interactions with commercial companies and the Naval Surface Warfare Center (NSWC), Annapolis Detachment, and a thorough review of the technical literature. This report presents several potential commercial technologies and their advantages and disadvantages. Out of the five different approaches to aluminum cladding, extrusion and electroplating methods are the least applicable due to their batch-type operations with inherently limited conductor plating length capability. The three other methods of aluminum cladding include radial wrapping, linear wrapping, and molten metal coating. While each method has technical challenges, all three have capabilities to continuously clad aluminum for the required conductor lengths. Benefits derived from a successful aluminum cladding technology include a 40-50% weight reduction over equally sized all-copper-stabilized wire, improved thermal stability (10 times) of the magnet system, and a 25-30% decrease in manufacturing cost. Based on the evaluative efforts at the NCEMT and the NSWC, the most technically feasible and affordable method will be selected for further development.