The co-extrusion of metal-sheathed high-temperature superconductors

The co-extrusion of copper cans containing Ag-clad high-temperature superco nductor (HTS) cores using a direct extrusion technique was investigated. Co mposite rods were produced by simultaneous cladding and consolidation of th e superconducting material, however, a range of deformation behaviour occur red, including core and sleeve fracture, non-uniform wavy core and sound fl ow. The flow patterns varied consistently as the initial core diameter (D-c i) and reduction ratio (R) were varied, allowing domains of specific deform ation behaviour to be defined. The large variation in flow behaviour was al so attributed to stiffness mismatch between the HTS core and the cladding m etal. (C) 2000 Published by Elsevier Science S.A. All rights reserved.