Fabrication of oxide superconducting wire by elongation suppressed rolling.

通过抑制伸长轧制制造氧化物超导线材。

• 批准号: 03452248
• 负责人: SAITO Yoshihiro
• 金额: $ 3.84万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452248/
• 关键词: high Tc superconductor; oxide superconductor; superconducting wire; satellite mill; asymmetric rolling; critical current density; cross rolling; elongation suppressed rolling; 異径ロ-ル圧延

Yttrium-based oxide super conductor sheathed in aluminum tube was rolled into tapes in order to simulate the deformation of oxide sheathed in silver tube. The effect of pass schedule on deformation of oxide core was studied. The lateral spread increases with increasing reduction per pass and with decreasing the diameter of tube before rolling. The well known results obtained in usual bulk rolling that the lateral spread increases with increasing roll gap ratio holds true in rolling of oxide sheathed in metal tube. Non uniform core distribution through longitudinal direction becomes notable when rolled in pass schedule with high reduction per pass. The effect of rolling condition on critical current of silver sheathed Bi-based oxide wire was studied. The tape of 2mm in thickness was rolled to 1mm in thickness (intermediate rolling) by satellite mill (elongation suppressed rolling, 3passes), asymmetric rolling (11passes) or conventional flat rolling (3passes), then rolled to tape of 0.2mm in thickness by flat rolling. The tape rolled by satellite mill exhibited highest Jc, though the superconductor/silver interface was irregular. Application of satellite mill rolling (8passes, 30stages, 2.5%/stage) or conventional rolling (30passes, 2.5%/pass) eliminates this irregularity. The mechanical deformation between two sintering processes (intermediate deformation) exerts a marked effect on Jc. The tape for which cross rolling is adopted as intermediate deformation exhibits higher Jc than that for which conventional rolling is adopted as intermediate rolling. The c axes of the grains of cross rolled tape are oriented nearly perpendicular to the plane of the tape with slight rotating components about longitudinal direction. Those of conventionally rolled tape are also oriented nearly perpendicular to the plane of the tape, but have slight rotating components about transverse direction. This difference in texture seems to induce the difference in Jc.

为了模拟银管护套氧化物的变形，将铝管护套的氧化超导体卷成带材。研究了道次制度对氧化芯变形的影响。侧向宽展随着单道次压下量的增加和轧前管材直径的减小而增大。常规大块轧制中得到的侧向宽展随辊缝比增大而增大的结论在金属管护套氧化物轧制中是成立的。在道次压下量较大的道次制度下轧制时，沿纵向的芯子分布不均匀变得明显。研究了轧制条件对银套铋系氧化物线材临界电流的影响。用卫星磨(延伸率抑制轧制，3道次)、不对称轧制(11道次)或常规平轧(3道次)将2 mm厚的带材轧制到1 mm厚(中轧)，然后通过平轧轧制到0.2 mm厚的带材。虽然超导体/银界面不规则，但卫星磨机轧制的带材具有最高的JC。采用卫星轧制(8道次，30道次，2.5%/道次)或常规轧制(30道次，2.5%/道次)消除了这种不规则性。两个烧结过程之间的机械变形(中间变形)对JC有显著影响。采用交叉轧制作为中间变形的带材比采用常规轧制作为中间轧制的带材具有更高的Jc。斜轧带材颗粒的c轴几乎垂直于带材平面，各成分沿纵向略有旋转。常规卷带的那些也几乎垂直于带的平面取向，但具有围绕横向的轻微旋转部件。这种质地的差异似乎导致了JC的差异。