Metallographic investigationof first full-sizehigh-Jc Nb_(3)Sn cable-in-conduit conductor aftercyclicloadingtests  

作　　者：Chao Dai Yunhao Liu Zichuan Guo Yu Wu Arend Nijhuis Tianjun Xue Zuojiafeng Wu Jinggang Qin 

机构地区：[1]Huainan New Energy Research Center,Huainan 232000,People’s Republic of China [2]University of Twente,Energy,Materials and Systems,Faculty of Science and Technology,Enschede 7500AE,Netherlands [3]University of Science and Technology of China,Hefei 230026,People’s Republic of China [4]Baiyin Non-ferrous Changtong Wire&Cable Co.Ltd,Baiyin,Gansu 730900,People’s Republic of China [5]Longteng Mechanical and Electrical Co.,Ltd,YiChun 336000,People’s Republic of China

出　　处：《Superconductivity》2024年第1期1-8,共8页超导（英文）

基　　金：supported by the National Key R&D Program of China(Grant No.2017YFE0301404);the Comprehensive Research Facility for Fusion Technology Program of China under Contract No.2018-000052-73-01-001228。

摘　　要：In order to verify the feasibility of applying high-Jc Nb_(3)Sn strand in fusion magnet,a full-size cable-in-conduit conductor(CICC)with short twist pitch(STP)cable pattern was manufactured and tested in SULTAN facility at SPC,Switzerland.Three levels of cyclic electromagnetic(EM)load were applied on the sample stepwise,no visible decrease of current sharing temperature(TcsT was observed until the EM load increased to 80 kA×10.8 T,after that the Tcs decreased dramatically with the EM cycles,which suggested that irreversible deformation,causing a change in the strain state,or even damage has occurred in the superconducting strands.For investigating the reason which caused the conductor performance degradation,the tested conductor was dissected for metallographic observation.Eight segments which subjected to different EM loads were extracted from one of the legs,the geometric feature changes of the cable cross-sections were analyzed and compared.A good correlation was found between the decrease of the Tcs and deformation of the cable cross section.A mass of cracks were found on the sub-elements of strands in the segment which subjected to highest EM load,but the amount of crack is much lower in other segments.Combining the analyses,it is speculated that the critical EM load which causes irreversible degradation is between 850 kN/m and 870 kN/m for this conductor.The results could be a reference in high-Jc Nb_(3)Sn CICC design.

关 键 词：High‐Jc Nb_(3)Sn Cable‐in‐conduit conductor METALLOGRAPHY 

分 类 号：O4[理学—物理]