Determination of active slip systems and morphological properties belonging to chromium doped Bi-2212 ceramic materials

The aim of this thesis is to experimentally explain the mechanical behavior, and morphological properties, respectively Vickers hardness measurement and scanning electron microscopy (SEM) analyzes of Cr doped Bi-2212 superconducting materials. The variation of the surface residual pressure stress regions and shear systems of the Bi-2212 ceramic matrix with Cr doping in the sample and its role on the main mechanical performance parameters of the Cr doped Bi-2212 superconductor samples were investigated. The experimental results obtained show that the mechanical strength, critical stress, hardness and durability of the material are strengthened against the movement of cracks and defects in the material. In the study, the variation of the main mechanical performance parameters, durable tetragonal phase and mechanical characteristic behavior of Cr-doped Bi-2212 ceramic materials, whose doping amount varies between 0.00-0.10 mole ratios, was investigated by micro-indentation Vickers hardness measurements under applied test loads of 0.245 N and 2.940 N.. In line with the results obtained, all experimental findings were perfectly confirmed by semi-empirical mechanical models. Both the experimental hardness results and the semi-empirical mechanical models showed that the doping rate seriously affects all mechanical properties and characteristics. In addition, among all semi-empirical mechanical methods, the IIC model was found to have the highest success in determining the original Vickers microhardness parameters in the plateau boundary region. The measurements detail the changes in the Bi-2212 crystal structure and the irreversible crystal structure problems that occur. SEM images show that Bi-2212 materials with optimum chromium ion contribution are suitable for use in advanced technological mechanical and energy efficient construction demands. Bi-2212 superconductors were analyzed by semi-empirical mechanical models such as Meyer's Law (ML), proportional sample resistance (PSR), modified proportional sample resistance (MPSR), Elastic-Plastic Deformation (EPD), Hays-Kendall (HK) and Indentation-Induced Cracking (IIC).