Superconducting properties depending on the processing parameters of Nb(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; pp. 1024 - 1027
• 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: 01.06.2004
• ISSN: 1051-8223
• DOI: 10.1109/TASC.2004.830384

Superconducting properties depending on the processing parameters of Nb(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(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)/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 Tc and the critical current density Jc of the Nb(3)Al wire after the RHQT treatment. The thinner the Nb/Al layers in the CCE-processed wire, the higher the Jc and Tc of the RHQT-treated Nb(3)Al wire. The as-quenched Nb(Al)/ss/ wire can be drawn to nearly 50% reduction at room temperature. Such cold working of the Nb(Al)/ss/ wire before transformation is an effective operation to improve Jc-B property of the transformed Nb(3)Al wire by the following treatment.