采用中子衍射研究内锡法Nb3Sn的相形成

Phase Formation Investigation of Internal-Sn Nb3Sn by in-Situ Nentron Diffraction

摘要:

选取2种ITER用内锡法Nb3Sn复合超导线，采用原位中子衍射测量技术检测超导相的形成过程，通过添加第3种元素研究合金化Sn芯和合金化Nb芯对超导相形成过程及超导线超导性能的影响。结果表明：合金化Sn芯比合金化Nb芯丝有利于提高超导性能；少量添加第3种元素Ti与Sn形成合金能显著促进Sn的扩散和A15相的形成，并且能有效抑制Nb3Sn晶粒的生长，因此增加了晶界面积和钉扎力，增强了超导特性，提高了非铜区临界电流密度Jcn。

Abstract:

Two kinds of ITER internal-Sn Nb3Sn superconducting wires were chosen to investigate the effects of Sn core or Nb core alloyed with the third element on A15 phase formation and superconducting performances in this paper.In-situ neutron diffraction was used for measurement of phase formation progress during the heat treatment procedure.From the obtained results it can be concluded that Sn core alloyed with small amount of the third element Ti is more effective than Nb core alloyed with Ta in enhancing A15 phase formation and improving superconducting performances.The reason may be as follows:small amount of Ti addition will not only greatly increase the tin diffusion rate and A15 phase formation rate,but also effectively inhibit the Nb3Sn grain growth and elevate the pinning force,resulting in obvious improving of superconducting performances and the large increment of non-Cu critical current density Jcn.