Speaker
Description
To develop superconducting wires suitable for applications demanding extremely high magnetic fields, we conducted an experimental investigation on the optimization of microstructure and heat treatment processes aimed at enhancing the critical current density (non-Cu Jc) at 16 T in Internal-tin type multifilamentary Nb3Sn superconducting wires fabricated in WST. Utilizing comprehensive analytical techniques, including Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and the Physical Property Measurement System (PPMS), we established a correlation between Nb3Sn grain refinement and the irreversibility field (Hirr). Our findings revealed that, under optimal growth conditions characterized by specific time and temperature parameters, where Nb3Sn grain size increased slightly, Hirr demonstrated the highest value, we obtained significantly enhanced performance at 16 T in these Nb3Sn wires. Specifically, by fine-tuning the Nb3Sn growth condition to 680°C for 80 h, we achieved an impressive Hirr of 27.42 T (4.2 K), and Jc was elevated to values exceeding 1300 A/mm² (4.2 K, 16 T), accompanied by an atomic percentage of Sn in Nb3Sn reaching 24 at.%, conditions conducive to Sn-rich Nb3Sn phases, representing one of the highest performances reported thus far for Ti-doped Nb3Sn wires. These findings pave the way for future advancements, suggesting that by optimizing the superconducting properties within such meticulously heat treatment processes, it is feasible to elevate Jc towards meeting 16 T or even higher magnet requirements in such Internal-tin Nb3Sn wires.
