Development and characterization of aluminum clad superconductors

A fabrication technique capable of high-volume production is described that was developed to clad conventional NbTi/Cu composite conductors with high-purity aluminum. Various sizes and shapes of practical superconductors were clad using aluminum of initial residual resistance ratios (RRR) ranging from 200:1 to 3000:1. The quality of bond between Al and Cu was investigated metallographically and by shear-strength tests. Electrical properties, such as the current-carrying capacity and RRR as a function of magnetic field for several Al-stabilized conductors, were measured. The results of the investigation are presented and the particular advantages of the Al-clad conductors over the fully copper-stabilized configurations are discussed. >