Superconducting properties depending on the processing parameters of Nb sub(3)Al wires by the clad-chip extrusion method and the rapid-heating, quenching and transformation treatment

• Published in: IEEE transactions on applied superconductivity Vol. 14; no. 2
• Main Authors: Saito, S, Sugawara, H, Yuuki, J, Kodaira, N, Kikuchi, A, Iijima, Y, Inoue, K, Takeuchi, T, Nimori, S, Kosuge, M, Yuyama, M
• Format: Journal Article
• Language: English
• Published: 01.01.2004
• Subjects: Aluminum; Cladding; Extrusion cladding; Niobium; Process parameters; Quenching; Transformations; Wire
• ISSN: 1051-8223
• DOI: 10.1109/TASC.2004.830384

Superconducting properties depending on the processing parameters of Nb sub(3)Al wire fabrication are presented. The adopted process consists of the clad-chip extrusion (CCE) method and the rapid-heating, quenching, and transformation (RHQT) treatment. The former (CCE) is a fabrication method for Nb/Al composite wire. It is characterized by the extrusion of thin chips of Nb/Al clad-rolled sheet. The latter (RHQT) is a heat-treatment method to transform the CCE-processed Nb/Al composite wire into the Nb sub(3)Al intermetallic compound. The focused processing parameters are the chemical composition and the thickness of Nb/Al layers in the composite, and the cold working of the bcc supersaturated solid solution Nb(Al) sub(ss) wire after the rapid-heating and quenching treatment. The results are as follows. A nearly stoichiometric composition of the CCE-processed precursor wire is optimum for enhancing the critical transition temperature T sub(c) and the critical current density J sub(c) of the Nb sub(3)Al wire after the RHQT treatment. The thinner the Nb/Al layers in the CCE-processed wire, the higher the J sub(c) and T sub(c) of the RHQT-treated Nb sub(3)Al wire. The as-quenched Nb(Al) sub(ss) wire can be drawn to nearly 50% reduction at room temperature. Such cold working of the Nb(Al) sub(ss) wire before transformation is an effective operation to improve J sub(c)-B property of the transformed Nb sub(3)Al wire by the following treatment.