The Influence of Na Addition on the Mechanical Properties of Bi-2212 Superconductors

In this work, the effects of Na doping on the mechanical properties of the samples are investigated by Vickers microhardness (Hv) measurements at room temperature. The highest microhardness values were obtained for Bi2Sr2Ca1Cu1.75Na0.25Oy sample including x = 0.25 Na content. On the other hand, the experimental results of Hv were compared with true microhardness values (H0) calculated by some theoretical approaches such as elastic/plastic deformation (EPD), proportional specimen resistance (PSR), and the Hays-Kendall models. All theoretic calculations also show that the sample with x = 0.25 Na content has the best mechanical properties. In addition, stress-strain curves of samples indicated that all samples protect their elastic properties at all applied loads. Finally, the surface roughness measurements of all the samples were done, indicating that they strongly depend on the content of Na substitution.