Multiple-pass warm extrusion of explosively compacted ceramic superconductive (Y-Ba-K-Cu-O)/metal billets

A. G. Mamalis, G. Pantazopoulos, A. Szalay, I. Kotsis, I. Vajda, D. E. Manolakos

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The fabrication of silver-sheathed Y(Ba,K)2Cu3O7 superconducting rods by explosive compaction and subsequent warm-plastic deformation, employing multiple-pass extrusion at 470°C, is reported and discussed. The impurity phase content, as well as the superconductivity of the component, were carefully controlled by employing intermediate and post-processing heat-treatment in flowing oxygen. The characterization of the extruded rod, after every extrusion pass, indicates a progressive microstructural refinement, leading to subsequent reduction of the porosity, closing of microcracks and enhancing the integrity of the metal/ceramic interface. Evaluation of the mechanical properties of the ceramic core-material, e.g. microhardness and fracture toughness, indicated significant improvement of the formability of the fabricated component. The various phase-transformations and transition temperature, Tc changes are presented and discussed, with respect to the manufacturing processes employed. Extruded rods, of 5 mm diameter and 50 mm length, are used as HTS conductors in a rotating electrical machine.

Original languageEnglish
Pages (from-to)213-229
Number of pages17
JournalApplied Superconductivity
Issue number5-6
Publication statusPublished - Jan 1 1996


ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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