Deformation of Mechanical Properties and Failure Behavior of Hays–Kendall Approach in Bi-2223 Superconducting Core After Eu Inclusions

Abstract

Mechanical features of Bi_1.8Pb_0.4Eu _x Sr₂Ca_2.2Cu₃O _y superconductor samples (x=0, 0.01, 0.03, 0.05, 0.07, 0.1, and 0.3) are elaborated by traditional solid-state reaction route. The deformation of the mechanical properties belonging to the Bi-2223 crystal structure by Eu impurities with the aid of Vickers hardness (H _v ) measurements are conducted at different indentation loads from 0.245 N to 2.940 N for the first time. Further, the H _v values extracted from experimental results are investigated using five different models so as to demonstrate the role of Eu addition on Bi-2223 samples. Based on these results, we observed that the undoped sample reveals the indentation size effect (ISE) feature, whereas the Eu-doped Bi-2223 superconducting core demonstrates the reverse indentation size effect (RISE) nature. Additionally, it is attained that the models (Meyer’s law, EPD, and PSR) fail to determine the estimate of the microhardness with the applied load. Nonetheless, the HK approach is observed to be superior to other models for the pure sample showing the ISE feature, while the IIC model is found to be the most successful model for the explanation of the mechanical characteristics of the Eu impurities in Bi-2223 bulk ceramics obeying RISE nature.