Post heat treatment time induced distinguished superconducting features of JR Nb3Al wires rapidly heated around the Tc peak condition. (July 2019)

• Record Type: Journal Article
• Authors: Yang, Changkun; Sun, Xiaguang; Li, Pingyuan; Yu, Zhou; Chen, Yongliang; Zhang, Yong; Pan, Xifeng; Yan, Guo; Feng, Yong; Zhao, Yong
• Is Part Of: Intermetallics. Volume 110(2019:Jul.)
• Publication Date: 2019-07
• Subjects: A. intermetallics -- B. phase transformation -- C. heat treatment -- D. grain boundary -- F. Scanning electron microscopy -- G. superconducting; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2019.106482
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: This work investigated the effect of post heat treat time on the structure and superconducting properties of Nb3 Al wires prepared around the current condition of getting T c peak. Properties of Nb3 Al wires rapidly heated at much lower current of 76 A were also studied for comparison. M-T results show that prolongation of post-heat treatment time can elevate the T c value of all Nb3 Al wires because of the stoichiometry improvement of Nb3 Al phase. The best J c of post heat treated Nb3 Al wires rapidly heated at 76 A and 272 A were obtained after post heat treated for 2 h at 800 °C, compared to that of 10 h for the 276 A samples. The different optimism post heat treatment time to get best J c of the wires might attribute to the disorder degree difference of the Nb(Al)ss phase fabricated under different rapid heating current. The main pinning mechanism of Nb3 Al superconducting wires was grain boundary pinning, as deduced from the fitting of pinning curve. Gradually degrade of J c of the Nb3 Al wire performed at longer heat treatment time was attributed to the coarse of Nb3 Al grain that attenuated grain boundary pinning. Highlights: Annealing induced distinguished feature of Nb3 Al wires rapidly heated around T c peak. The increase of post-heat treatment time can improve their T c and the stoichiometry. Best J c obtained in 2 h annealed Nb3 Al wires when heating at left side of T c peak. Longer time is required to get best J c of the wires heated at right side of T c peak.