Through magnetization measurement with a SQUID magnetometer the heat treatment optimization of an international thermonuclear experimental reactor （ITER）-type internal-Sn Nb3Sn superconducting wire has been investig...Through magnetization measurement with a SQUID magnetometer the heat treatment optimization of an international thermonuclear experimental reactor （ITER）-type internal-Sn Nb3Sn superconducting wire has been investigated. The irreversibility temperature T^＊ （H）, which is mainly dependent on A15 phase composition, was obtained by a warming and cooling cycle at a fixed field. The hysteresis width △M（H） which reflects the flux pinning situation of the A15 phase is determined by the sweeping of magnetic field at a constant temperature. The results obtained from differently heat-treated samples show that the combination of T^＊ （H） with AM（H） measurement is very effective for optimizing the heat reaction process. The heat treatment condition of the ITER-type wire is optimized at 675℃/128 h, which results in a composition closer to stoichiometric Nb3Sn and a state with best flux pinning.展开更多
The effects of annealing on microstructure, posite wire have been investigated. Neither changes in magnetoresistance, and hardness of an in situ Cu-Nb microcom- microstructure nor hardness were found until 500 ℃. Par...The effects of annealing on microstructure, posite wire have been investigated. Neither changes in magnetoresistance, and hardness of an in situ Cu-Nb microcom- microstructure nor hardness were found until 500 ℃. Particularly, microstructural change within the Nb films was observed in the annealed samples. The room-temperature magnetoresistivity was almost negligible, while magnetoresistivity at -196℃increased with magnetic field. At temperature above 500 ℃, recovery and recrystallization occurred, and both the resistance and hardness decreased.展开更多
高铜比NbTi/Cu超导线材(Wire in Channel,WIC)具有低成本、所制备的磁体稳定性高等优点,是高铜超比超导线材的主要产品之一,被广泛应用于3 T以下的磁共振成像(MRI)系统的超导磁体.研究了WIC超导线材(NbTi线)的制备过程及其工艺,制备了...高铜比NbTi/Cu超导线材(Wire in Channel,WIC)具有低成本、所制备的磁体稳定性高等优点,是高铜超比超导线材的主要产品之一,被广泛应用于3 T以下的磁共振成像(MRI)系统的超导磁体.研究了WIC超导线材(NbTi线)的制备过程及其工艺,制备了铜超比为10.9∶1的WIC超导线材,并对其性能进行了测试.结果表明,所制备的WIC超导线材其耐电压强度高于1 000 V,RRR值高于140,临界电流密度高于2 800A/mm2(4.2K@5T),能够满足使用要求.展开更多
文摘Through magnetization measurement with a SQUID magnetometer the heat treatment optimization of an international thermonuclear experimental reactor （ITER）-type internal-Sn Nb3Sn superconducting wire has been investigated. The irreversibility temperature T^＊ （H）, which is mainly dependent on A15 phase composition, was obtained by a warming and cooling cycle at a fixed field. The hysteresis width △M（H） which reflects the flux pinning situation of the A15 phase is determined by the sweeping of magnetic field at a constant temperature. The results obtained from differently heat-treated samples show that the combination of T^＊ （H） with AM（H） measurement is very effective for optimizing the heat reaction process. The heat treatment condition of the ITER-type wire is optimized at 675℃/128 h, which results in a composition closer to stoichiometric Nb3Sn and a state with best flux pinning.
基金funded by the National Natural Science Foundation of China(Grant Nos.51421001 and 51301040)the Natural Science Foundation of Fujian Province of China(No.2016J05119)+1 种基金the Science and Technology Fund from Fujian Education Department of China(Grant No.JA15072)supported by US National Science Foundation Cooperative Agreement No.DMR-1157490
文摘The effects of annealing on microstructure, posite wire have been investigated. Neither changes in magnetoresistance, and hardness of an in situ Cu-Nb microcom- microstructure nor hardness were found until 500 ℃. Particularly, microstructural change within the Nb films was observed in the annealed samples. The room-temperature magnetoresistivity was almost negligible, while magnetoresistivity at -196℃increased with magnetic field. At temperature above 500 ℃, recovery and recrystallization occurred, and both the resistance and hardness decreased.
