Investigation of superconducting degradation and damage detection of Bi2223 composite superconducting tape after tensile stress

In this study, the damage level and morphology of Bi2223 composite superconducting tapes subjected to severe tensile stress were investigated using four detection methods: the four-probe, 2D-Hall, magneto-optical, and micro-computed tomography (micro-CT). A new detection procedure was developed to detect micrometre-sized damaged areas in a 10 cm-long Bi2223 composite superconducting tape. The four detection methods showed different spatial resolutions and sensitivity to damage level and area. These were systematically compared in this study. The four-probe method provided the highest level of accuracy in evaluating I c degradation. However, it showed a spatial resolution of 1 cm. In contrast, submicron-sized structural variations in three dimensions (3D) were differentiated in Bi2223 using micro-CT. However, the damaged area required a subjective assessment, decreasing the accuracy of damage detection. A prototype phenomenological model was also developed, which linked tensile damage to the resulting 3D morphology. This investigation can assist Bi2223 magnet researchers in analysing damaged magnets and determining whether the damage is owing to tensile stress. • The tensile damaged level and morphology were detected by the I–V method, 2D-Hall, Magneto-optical, and micro-CT. • The micro-CT can differentiate the submicron size structure change in the Bi2223, but the damaged area needs subjective judgment. • A phenomenological model between the tensile damage and 3D morphology from micro-CT was established.