Properties variation of Bi-2212 directionally solidified induced by 0.4Pb substitution

Vitreous cylinders with compositions Bi2−xPbxSr2CaCu2Oy (x = 0 and 0.4) were prepared and used as precursors to fabricate textured bars through a laser floating zone melting method (LFZ). The resulting textured cylindrical bars, after annealing, were electrical and mechanically characterized through resistivity as a function of temperature, E–I characteristics at 77 K, mechanical strength, σ, Young modulus, EY, Vickers hardness, Hv, and Weibull parameters, S0 and m. The study of the mechanisms controlling the fracture process was made by means of the fractographical analysis using laser scanning confocal microscopy (LSCM). It has been found that the Pb addition lead to an increase of the slope of the E–I curves and to a change in the fracture mode.