Thermal stress analysis and lifetime prediction of solder joints for superconducting tapes using the Coffin–Manson model

Since their invention, high-temperature superconductors (HTS) have been widely applied as current leads for superconducting coils because of the advantages they offer in terms of the operating temperature and cost, performance in the presence of a magnetic field, and thermal leakage prevention. Unfortunately, due to the existence of soldered parts, the mechanical stability of a HTS current lead cannot be the same as that of a conventional current lead manufactured from a non-superconducting metal. Attempts to overcome this problem have prompted research on the analysis of past experiences and the causes of accidents involving operating current leads. However, the effect of thermal stress on operating current leads is insufficiently understood and fundamental tools for the prediction and prevention of failure are not readily available. In this study, we examined whether the Coffin–Manson …