Compressive mechanical properties of Sm123 bulk superconductor at liquid nitrogen temperature

In order to investigate the compressive mechanical properties of a single-grain Sm123 bulk superconductor at cryogenic temperature, compressive tests at liquid nitrogen temperature on small specimens with the dimensions of 3 × 3 × 8 mm 3 cut from the bulk with 45 mm in diameter and 15 mm in thickness were carried out. Due to the closure of pre-existing micro-cracks perpendicular to the c -axis, the average Young’s modulus in the c -axis, 93 GPa, was lower than that in the direction perpendicular to the c -axis, 150 GPa. While the former was higher than the value at room temperature (RT), 75 GPa, the latter was slightly lower than that, 165 GPa. The compressive strength in the c -axis, 466 MPa, was higher than that in the direction perpendicular to the c -axis, 368 MPa. This anisotropy is also ascribed to the pre-existing micro-cracks associated with the fracture mode. Both the former and the latter were higher than the values at RT, 350 and 335 MPa, respectively. Most of the specimens loaded in perpendicular to the c -axis fractured along the plane perpendicular to the c -axis into a few pieces. The specimen loaded in the c -axis fractured into many small fragments, although the specimen with extraordinarily low strength fractured in a similar mode as mentioned above.