内锡法Nb3Sn超导线A15相组成及TC的特征研究（英文）

设计并制备四组不同组成的内锡法Nb3Sn单组元线和两组不同结构设计的多芯线.先将所有样品进行210℃/50hr+340℃/25hr的Cu-Sn合金化热处理,接着进行A15相成相热处理.四组单组元线的成相热处理程序是在675oC,700oC和725℃三种温度下热处理100小时和200小时;而两组多芯线的成相热处理程序是在675℃,675℃,700℃和725℃四种温度下热处理128小时和200小时.将所有热处理样品采用X-射线EDS进行A15相组成分布测定,采用SQUID磁化法测定临界温度TC.所得结果表明,经过足够热处理时间后各种内锡法Nb3Sn超导线的最终A15相组成和TC与热处理温度、导线复合体组成和结构设计以及第三元素的合金化掺杂无关,而是由这种扩散与固相反应的机制本质所决定的.

CHARACTERIZATION STUDY OF A15 PHASE COMPOSITION AND T_C IN Internal-Sn Nb_3Sn STRANDS

Four sets of mono-element and two kinds of multifilament internal-Sn Nb3Sn superconducting strands were devised and fabricated,in which various component ratio,different composite configurations and some third element addition were arranged.All strand samples carried out a 210℃/50hr + 340℃/25hr thermal duration for Cu-Sn mixing.After that A15 phase formation heat treatment (HT) was applied for which the four ME strands were chosen at three reaction temperatures of 675℃,700℃ and 725℃ for 100hrs and 200hrs,while the two MF strands at four temperatures of 650℃,675℃,700oC and 725℃ for 128hrs and 200hrs.The heat-reacted strand samples were examined for A15 phase composition distribution by X-ray EDS and were measured critical temperature TC by means of SQUID magnetization measurement.The obtained results indicate that for sufficiently-reacted internal-Sn Nb3Sn superconductors the A15 phase composition and the intrinsic property TC are determined by the diffusion and solid reaction mechanism of A15 phase formation and are independent on the factors including HT temperature,strand composite component and configuration arrangement,and the third alloyed-element.