Texturing and grain growth behaviour of (Bi,Pb) 2Sr2Ca2Cu3O10+x superconducting oxide during annealing

The grain alignment in the deformed Bi2223 superconductor tapes can be improved by mechanical deformation and thermal treatment. The present research studies the mechanisms of the texturing and grain growth processes in the deformed Bi2223 superconductor tapes during annealing. The results indicate that the texturing processes can be divided into two independent stages with different mechanisms. The first stage of the texturing process was the reconnection of the fractured crystals which resulted from mechanical deformation. The second stage was dominated by the recrystallisation and growth of the crystals. There are also two different grain growth mechanisms in the deformed Bi2223 superconductors during the recrystallisation annealing: `ledge-growth' and `screw dislocation-growth' mechanisms. The distinctive texturing and grain growth behaviours of Bi2223 oxide during recrystallisation are related to the plate-like microstructure and the brittle nature of the oxide.