TY - JOUR
T1 - Deformation and fracture characteristics and its effect on the superconductivity of a high Tc superconductor (YaBa2Cu3O7-x)
AU - Shoji, Tetsuo
AU - Tazawa, Yasushisa
N1 - Funding Information:
This work was performed under the support of Grant-in-Aid for General Scientific Research 01420020 from the Ministry of Education, Science and Culture, Japan.
PY - 1991/9/15
Y1 - 1991/9/15
N2 - In this paper, the effects of current supply on the mechanical properties of a sintered bulk YBa2Cu3O7-x (YBCO) superconductor were studied. The tensile strength and fracture toughness were measured by the Brazilian test and on round compact tension specimens respectively. During these tests, current was repeatedly supplied to the specimens through current probes, and the superconductivity was monitored by voltage-monitoring probes during the tests. In general, a transition from the superconducting state to the normal conducting state was observed only at the final unstable failure, and no effects of microcracking and stable crack growth during loading on superconductivity were found. However, during fracture toughness testing, reproducible anomalies in load-crack-mouth-opening displacement (CMOD) curve was observed associated with the on-ff switching of the repeated current supply. These anomalies in load-CMOD curves can be attributed to anisotropic thermal expansion depending upon the direction of current supply to the specimens. This behaviour was also confirmed by repeated current supply tests on bulk specimens with two strain gauges adhering to the specimen surface. As a consequence, this behaviour was thought to result from the local quenching of YBCO and subsequent local heat generation in the specimens.
AB - In this paper, the effects of current supply on the mechanical properties of a sintered bulk YBa2Cu3O7-x (YBCO) superconductor were studied. The tensile strength and fracture toughness were measured by the Brazilian test and on round compact tension specimens respectively. During these tests, current was repeatedly supplied to the specimens through current probes, and the superconductivity was monitored by voltage-monitoring probes during the tests. In general, a transition from the superconducting state to the normal conducting state was observed only at the final unstable failure, and no effects of microcracking and stable crack growth during loading on superconductivity were found. However, during fracture toughness testing, reproducible anomalies in load-crack-mouth-opening displacement (CMOD) curve was observed associated with the on-ff switching of the repeated current supply. These anomalies in load-CMOD curves can be attributed to anisotropic thermal expansion depending upon the direction of current supply to the specimens. This behaviour was also confirmed by repeated current supply tests on bulk specimens with two strain gauges adhering to the specimen surface. As a consequence, this behaviour was thought to result from the local quenching of YBCO and subsequent local heat generation in the specimens.
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U2 - 10.1016/0921-5093(91)90743-7
DO - 10.1016/0921-5093(91)90743-7
M3 - Article
AN - SCOPUS:0026221135
SN - 0921-5093
VL - 143
SP - 241
EP - 245
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
IS - 1-2
ER -