Mechanical Properties of Superconducting (Gd,Y)BaCuO Large Single-Grain Material Fabricated by RE Compositional Gradient Technique

In order to investigate the mechanical properties of a (Gd,Y)BaCuO large single-grain bulk material, bending tests were carried out at room temperature for the specimens cut from the bulk material. A precursor, which consisted of three regions with different Gd and Y contents, was used for the fabrication of the large single-grain bulk material in order to overcome the undesirable nucleation apart from the seed crystal. The precursor was prepared such that Y content increased with increase in the distance from the center, where the seed crystal was placed, to decrease the peritectic decomposition temperature. Two types of bending test specimens were cut from the bulk material-the specimens that included the interface between two regions with different Gd and Y contents and the specimens that did not include the interface. Although the bending strength data of the specimens that did not include the interface scattered widely in comparison with the specimens that included the interface, the average bending strength values of these specimens were similar to each other. This result demonstrates that the interface does not cause the deterioration of the mechanical properties of the whole bulk material.