TAHSİN TURĞAY, YUSUF ZALAOĞLU, GÜRCAN YILDIRIM

Key mechanical Design Performance Features and Mechanical Characterization of Poly-crystallized Bi2.1Sr2.0-xTixCa1.1Cu2.0Oy Superconducting Ceramic Cuprates

The primary scope of this study is to examine the variations of key mechanical design performance features and mechanical characterization of Bi2.1Sr2.0-xTixCa1.1Cu2.0Oy superconductors via Vickers hardness tests performed at different test loads between 0.245 N and 2.940 N. The materials are prepared within the molar ratios of 0≤x≤0.10 by using the ceramic method in the atmospheric air. The measurement findings obtained indicate that the increment of Sr/Ti partial substitution level regresses remarkably the key design mechanical performances namely mechanical strength, stability, stiffness, critical stress, toughness, flexural strengths and mechanical durability. This means that the existence of Ti impurity matrix leads to the enhancement in the problematic defects, crack initiation sites and stress raisers based on the crack-producing omnipresent flaws. Accordingly, the propagation of the problematic defects accelerates considerably at lower indentation test loads applied, and the problematic defects locate easily in their critical propagation speed. All in all, the crystal defects are out of control, and the Sr/Ti partial substituted Bi2.1Sr2.0-xTixCa1.1Cu2.0Oy superconductiors are much easier broken. Additionally, it is noted that every material produced show the typical indentation size effect but in diminish trend with enhancing Sr/Ti partial replacement level. The load-dependent mechanical parameters such as Young’s modulus, yield strength, fracture toughness, brittleness index and elastic stiffness coefficients are also discussed in the text.

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