挤压过程中NbTiTa复合体的微观组织变化

Microstructure Evolution of NbTiTa Composite after Extrusions

摘要:

研究了以Nb,Ti,Ta片为原料制备NbTiTa超导线材的工艺中各次挤压后NbTiTa复合体的微观组织以及复合体中各片层间的扩散行为.结果表明:挤压过程中复合体的温度升高和塑性变形造成的大量晶体缺陷使复合体中Nb,Ti,Ta片间发生了严重的互扩散.由于互扩散复合体中形成了非超导的富Ti区和超导的富Nb区和富Ta区,富Ti区的体积百分数超过30%,而且富Ti区、富Nb区和富Ta区的横界面在挤压和拉拔过程中都最终演变成了条带状.

Abstract:

Using sheets of Nb, Ti and Ta as starting material, NbTiTa superconducting filaments were prepared by extrusion and drawing. The microstructure evolution of the composite after extrusions and the diffusion among Nb, Ti and Ta in the composite were studied. It is found that a large number of crystal defects and the temperature increment appeared, which is caused by the large plastic deformation during hot extrusions, as a result, the Nb, Ti, and Ta sheets diffused each other heavily. The non-superconducting Ti-rich area and superconducting Nb-rich area and Ta-rich area formed during extrusions. The volume percentage of Ti-rich area exceeded 30%, and the transects of Ti-rich area, Nb-rich area, and Ta-rich area all evolved into ribbon-like shape in extrusions and drawing.