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 recalescence behavior of undercooled Co-Sn alloys under static magnetic fields was investigated using glass slag fluxing technique in a 12T superconducting magnet.Results indicated that the nucleation temperature ...The recalescence behavior of undercooled Co-Sn alloys under static magnetic fields was investigated using glass slag fluxing technique in a 12T superconducting magnet.Results indicated that the nucleation temperature and the highest temperature after recalescence of undercooled melt can be affected by the static magnetic field.The undercooling for Co-Sn alloys keep unchanged when a strong magnetic field was applied while the recalescence extent was reduced. With the increasing Co content for Co-Sn eutectic systems,the effect of the magnetic field on the recalescence was strengthened.We find that the magnetic field has very limited effect on the nucleation temperature on alloys while the highest temperature after recalescence is affected by the field depending on the magnetization difference of the undercooled melt before and after solidification.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Item Sponsored by European project "MAGPRO"(RFSR-CT-2006-00019)National Basic Research Program of China(Grant No.2011CB610404)
文摘The recalescence behavior of undercooled Co-Sn alloys under static magnetic fields was investigated using glass slag fluxing technique in a 12T superconducting magnet.Results indicated that the nucleation temperature and the highest temperature after recalescence of undercooled melt can be affected by the static magnetic field.The undercooling for Co-Sn alloys keep unchanged when a strong magnetic field was applied while the recalescence extent was reduced. With the increasing Co content for Co-Sn eutectic systems,the effect of the magnetic field on the recalescence was strengthened.We find that the magnetic field has very limited effect on the nucleation temperature on alloys while the highest temperature after recalescence is affected by the field depending on the magnetization difference of the undercooled melt before and after solidification.
