Mechanical properties of YBCO and YBCO+ZnO polycrystalline superconductors using Vickers hardness test at cryogenic temperatures

Vickers hardness tests were carried out on YBCO and YBCO + 1 wt% ZnO polycrystalline superconductors from 40 to 293 K. It was found that the hardness was increased with 1 wt%ZnO addition to YBCO. Thermal activation energies of samples YBCO and YBCO + 1 wt%ZnO were found to be 0.0036 and 0.0026 eV, respectively. No creep was observed in the load-displacement experiments carried out for both samples at low temperatures, when the load was kept fixed for 15 s. It was detected that elastic recovery ratio of the 1 wt%ZnO added YBCO sample was higher than that of YBCO at both low temperature and room temperature. (C) 2004 Elsevier B.V. All rights reserved.