Peikuo Gao

Fabrication of the Textured Ni-9.3at.%W Alloy Substrate for Coated Conductors

It is difficult to obtain a sharp cube texture in the Ni-9.3at.% W substrate used for coated conductors due to its low stacking fault energy. In this paper, the traditional cold rolling procedure was optimized by introducing an intermediate recovery annealing. The deformation texture has been improved after three recovery annealing cycles at 500°C for 2 h during the cold rolling process. After optimized recrystallization annealing, a Ni-9.3at.% substrate with a cube texture content of 87.7% (<;10°) has been obtained. The effect of the intermediate annealing on cube texture formation is attributed to the improved deformation texture and to the enhanced pre-existing cube oriented structure in the deformed matrix.

Stable cube texture in an advanced Ni alloy composite substrate prepared by powder metallurgic method

Thin, reinforced and biaxially textured Ni5W/Ni12W/Ni5W composite substrate for coated conductor applications has been fabricated by traditional powder metallurgy method using the sparking plasma sintering (SPS) technology, followed by cold rolling and annealing. In-situ EBSD strain-stress analysis shows that the yield stress (δ0.2) can reach 240MPa. The high quality of cubic texture and boundaries of low misorientation angle were stable until elongations as high as 2%. Meanwhile, the cubic grain fractions on surfaces of top Ni5W layer of the composite tapes are 98.3%, 99.5% and 99.8%, respectively, corresponding to be annealed at 1250°C for 60min, 120min and 180min, indicating the cube texture can successfully sustain after severe treatment condition.