Mechanical properties of Y3−xNdxBa5−xCaxCu8O18−δ samples

Vickers microhardness measurements of Y3−xNdxBa5−xCaxCu8O18−δ samples, 0.00 ≤ x ≤ 0.40, were carried out at room temperature at different applied loads varies from 0.25 N to 10.00 N. Vickers microhardness decreases as the substitution content increases, as well as it decreases as the applied loads increase. The results were analyzed using different models such as Meyer's law, Hays-Kendall (HK) approach, elastic/plastic deformation (EPD) model, proportional specimen resistance (PSR) model and modified proportional specimen resistance (MPSR) model. The analysis shows that the MPSR model is the most suitable one to describe the load independent microhardness for Y3−xNdxBa5−xCaxCu8O18−δ superconducting samples at high load. Some important mechanical parameters such as Young's modulus (E), yield strength (Y), fracture toughness (Kf) and brittleness index (Bi) were calculated as a function of substitution content. The results show that they decrease by increasing the substation content for Y3−xNdxBa5−xCaxCu8O18−δ samples.