Speaker
Mr
Yigong Shi
(Western Superconducting Technologies Co., Ltd.)
Description
Two kinds of Nb3Sn multifilamentary wires were produced using the internal tin process. For comparison, ITER type wires used in ITER TF coils were also prepared. The fabrication process of these strands was the same and the only difference was the diameter of the wires. All the samples were heat-treated in vacuum using the ITER heat treatment cycles B. Reaction heat treatments at 650℃ were performed for 100h, 125h, 150h, 175h, 200h, 225h and 250h. The content of tin in filaments was studied by SEM and EDS analysis. The critical current densities in the non-Cu areas of 1.0mm and 1.5mm diameter wires were 871A/mm2 and 799A/mm2 at 12 T, 4.22K after 650℃×100h heat treatment, lower than ITER type wires with 0.820mm diameter, 1050 A/mm2. The EDS analysis indicated that higher content of unreacted Nb was observed in 1.5mm diameter wire because of the large size of the filaments. With the increase of heat treatment time, the Nb3Sn reaction layer grew gradually. The Jc of these wires enhanced to 1062A/mm2 and 1034A/mm2 after 650℃×250h heat treatment. The effect of heat treatment time on hysteresis losses of the wires are currently under research.
Primary author
Mr
Yigong Shi
(Western Superconducting Technologies Co., Ltd.)
