Development of APC NbTi superconductors with internal high purity aluminum stabilizer

It has long been known that high purity aluminum is superior to copper as a stabilizer for NbTi conductors, due primarily to its low density and excellent low temperature thermal and electrical conductivity. Unfortunately, it is difficult to co-process high purity aluminum with conventional NbTi conductors due to mechanical and diffusional problems caused by precipitation heat treatment, Supercon NbTi artificial pinning center (APC) material makes it possible to eliminate these problems. The concept has been demonstrated in APC composites containing /spl sim/15% high purity aluminum by volume. The recent development effort will be described and the results of mechanical and electrical testing will be given.