Effects of silver additions on resistance to thermal shock and delayed failure of YBa2Cu3O7−δ superconductors
- 1 June 1993
- journal article
- Published by Springer Nature in Journal of Materials Research
- Vol. 8 (6), 1226-1231
- https://doi.org/10.1557/jmr.1993.1226
Abstract
The effect of silver (Ag) addition on the resistance to thermal shock and delayed failure of YBa2Cu3O7−δ superconducting wires has been evaluated. Resistance to thermal shock was evaluated by measuring the critical-current density (Jc) as a function of the number of thermal cycles for YBCO and its composites with 15 vol. % Ag additions. Composite YBCO-Ag wires show a slower decrease in Jc than does monolithic YBCO as the number of thermal cycles increases. The nature of delayed failure was studied by measuring strength (σf) as a function of loading rate (σ) and evaluating the value of the subcritical crack growth parameter N[σf = Aσ1/(N+1)]. The value of the N parameter was observed to increase slightly from 35 for YBCO to 41 for YBCO-Ag composites. The improved resistance to thermal shock and subcritical crack growth is believed to be due to improvements in mechanical properties (strength and fracture toughness) and thermal conductivity of YBCO as a result of Ag addition.Keywords
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