A multifilament Nb/sub 3/Sn conductor containing Nb/Ta composite filaments was manufactured using bronze route processing. The Ta inclusions deformed uniformly during the fabrication process with little ductility problems. Ta to Ta spacings of less than 60 nm were obtained at final wire sizes. Samples were reacted using various heat treatment conditions and compared to a multifilament Nb(Ti)/sub 3/Sn conductor processed from a Nb 1.5 Ti alloy. The Ta inclusions reduce the grain growth of the A15 phase during the final reaction heat treatment and were responsible for a 15-20% increase in J/sub c/ (9 T, 4.2 K) as compared to the Nb(Ti)/sub 3/Sn wire. In addition, Ta dissolved in the A15 phase resulted in an enhanced upper critical field. Improvement of the filament uniformity through the use of fine-grained sheets was confirmed by magnetization and image analysis.
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机译:使用青铜路径加工制造包含Nb / Ta复合细丝的复丝Nb / sub 3 / Sn导体。 Ta夹杂物在制造过程中均匀变形,几乎没有延展性问题。在最终的导线尺寸下,Ta与Ta的间距小于60 nm。使用各种热处理条件使样品反应,并与由Nb 1.5 Ti合金加工而成的多丝Nb(Ti)/ sub 3 / Sn导体进行比较。 Ta夹杂物减少了最终反应热处理过程中A15相的晶粒长大,与Jb / sub c /(9 T,4.2 K)相比,Nb(Ti)/ sub增加了15-20% 3 / Sn线。另外,溶解在A15相中的Ta导致增强的上临界场。通过磁化和图像分析证实了通过使用细颗粒片材来改善长丝均匀性。
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