THE EFFECTS OF MECHANICAL DEFORMATION ON THE LATTICE DISTORTION AND GRAIN THICKNESS OF (BI,PB)(2)SR2CA2CU3O10+X OXIDE CRYSTALS

Mechanical deformation is widely used to produce grain aligned microst ructure in (Bi,Pb)(2)Sr2Ca2Cu3O10+x (Bi-2223) superconducting tapes. M icrostructural changes including fracture of grains, lattice distortio n and dislocations are introduced by the deformation processes. The pr esent paper uses precise X-ray diffraction and Fourier transformation to study the microscopic features of the Bi-2223 oxide with different mechanical deformation: lattice distortion and plate-like grain thickn ess. The results indicate that the lattice distortion in the Bi-2223 c rystals increases with increasing deformation rate, and the thickness of the plate-like Bi-2223 crystals decreases with increasing deformati on. Lattice distortion provides energy for the subsequent recrystalliz ation processes of the Bi-2223 oxide, but it does not have significant effect on the final grain size after annealing. It is believed that t he grain size after annealing is mainly determined by the grain size a fter the mechanical deformation. (C) 1998 Elsevier Science B.V.