Ultrafine fiber in situ Cu-Nb-Sn produced by high temperature gradient solidification

The high temperature gradient solidification (HTGS) technique to obtain a random dispersion of the niobium in the copper matrix is described. The equipment has been modified to accept larger and available graphite tubes. Examples of microstructure control are given and versatility of the technique is illustrated by the addition of iron to the Cu-Nb starting coaxial rod. Following solidification, the iron dispersion was analyzed using EDX, Auger and atomic absorption. The iron is mainly in the niobium dendrites but does not degrade the overall Jc= 10⁴A/cm²at 16 tesla.