Evaluation of mechanical properties of Dy123 bulk superconductors by 3-point bending tests

In order to evaluate the mechanical properties, such as Young's modulus and strength, of Dy123 bulk superconductors and those with 10 wt.% Ag₂O, we performed 3-point bending tests at room (RT) and liquid nitrogen temperatures (LNT) using specimens cut from the bulks. The Young's modulus and the bending strength increased with decrease in temperature. In the tests loading in the direction of c-axis and ones perpendicular to it, Young's moduli were almost comparable at both RT and LNT. Although the strengths for both orientations were also comparable at LNT, those at RT were different. Young's moduli loaded in the direction of c-axis for Ag₂O added bulk specimens, 127 GPa in average at RT, were almost comparable to those without Ag₂O, and 134 GPa at LNT, were slightly lower than those without Ag₂O. On the other hand, the strengths at both RT and LNT were enhanced by 20% by the Ag addition. The mechanical properties of Dy123 bulks without Ag₂O were compared with those of Y123 bulks obtained previously. The Young's modulus for loading in the direction of c-axis was slightly lower, and the strength was comparable to those in Y123 bulks, respectively.