Tensile Properties of DyBaCuO Low Porosity Bulk Material Melt-Processed in Oxygen Atmosphere

Abstract

Mechanical properties of a DyBaCuO single-grain superconducting bulk material obtained through the melt-processing in 100% O2 atmosphere were evaluated through tensile tests for the specimens cut from the bulk material. DyBaCuO bulk materials melt-processed in 50 and 75% O2 atmosphere were also evaluated for comparison. The porosity was decreased with increasing the O2 pressure in the melt-processing, and few pores were observed for the bulk material melt-processed in 100% O2 atmosphere. The tensile test specimens were glued to metal rods, and the metal rods were connected to the universal joints for loading. The tensile strength was improved with decreasing the porosity. The tensile strength values obtained in this study were lower than bending strength values reported elsewhere. Flow-like patterns formed by the crack propagations were observed on the fracture surfaces of the tensile test specimens. Through the observations on the fracture surfaces, differences in the fracture mechanisms between the porous and the low porosity bulk materials are discussed.