涂层导体用Ni9W合金基带再结晶及强立方织构的形成研究

采用X射线四环衍射技术对比分析了通过冷轧和轧制中间热处理制备的2种Ni-9.3at%W(Ni9W)合金基带的轧制织构和再结晶织构,研究了不同Ni9W合金基带在热处理过程中轧制织构向再结晶织构的演变。其次,采用背散射电子衍射(EBSD)技术对以上2种Ni9W合金基带的微观组织和立方织构进行了表征。结果表明,与传统冷轧Ni9W合金基带的轧制织构相比,经轧制中间热处理后其轧制织构中S取向和Copper取向的含量增加、Brass取向的含量减少,使其轧制织构的类型介于Brass型轧制织构与Copper型轧制织构之间。2种Ni9W合金基带经低温回复后,其轧制织构含量均有一定的增加;另外,再结晶过程中轧制织构的含量均迅速降低,但立方取向的含量并没有明显增加,而是出现大量的随机取向,Ni9W的再结晶具有了连续再结晶的特征,这也是导致Ni9W合金基带较难形成立方织构的一个主要原因。虽然经过轧制中间热处理后Ni9W合金基带在初始再结晶完成后并没有形成一定强度的立方织构,但其立方取向的含量仍然能在进一步热处理过程中通过立方取向晶粒的长大而得到加强。最后,采用轧制中间热处理制备的Ni9W合金基带经两步高温热处理后其立方织构的含量达到84.5%(15°)。

Recrystallization and Cube Texture Formation of Ni9W Alloy Substrate for Coated Conductors

Deformation and recrystallization textures of Ni9W alloy tapes deformed by cold rolling with and without intermediate annealing were investigated by XRD, which indicated the texture transition between rolling and recrystallization textures during annealing. Furthermore, the microstructure and cube texture of Ni9W alloy substrates were studied by electron back scattered diffraction (EBSD). The results show that there are more fractions of S and Copper orientations as well as less Brass orientations in the rolling texture of Ni9W alloy tapes cold rolled with intermediate annealing, resulting in a mixed rolling texture between Brass type and Copper type. The fractions of rolling texture for both Ni9W tapes are increased during a long-term recovery, and then decreased significantly in recrystallization process. But, the fraction of cube orientation does not increase obviously, while a large amount of random orientation forms during recrystallization. The recrystallization of the Ni9W alloy is continuous, which is one of the main reasons for rough cube texture formation in Ni9W substrates. Though there is no strong cube texture formed after primary recrystallization for the Ni9W taps cold rolled with intermediate annealing, the fraction of cube orientation can be enhanced during grain growth with high temperature annealing. At last, strong cube texture fraction of 84.5% (< 15°) is obtained by two-step annealing for the Ni9W substrates deformed by cold rolling with intermediate annealing