A study of the microscopic deformation behavior of Nb3Sn composite superconducting tape using the acoustic emission technique

Abstract Nb 3 Sn-based composite superconducting tapes have been widely used because of their excellent properties such as high critical current density, low AC loss and high critical temperature. However, one of the disadvantages of Nb 3 Sn-based composite superconducting tape is that the Nb 3 Sn compound often exhibits multiple cracking owing to its intrinsic brittleness when subjected to mechanical loading such as bending, winding, and operation. Such cracking eventually causes severe degradation of the critical current density. Therefore, it is very important to understand the microscopic deformation behavior of Nb 3 Sn-based composite superconducting tape under mechanical loading. In this study, the microscopic deformation behavior and the fracture mechanism of Nb 3 Sn-based composite superconducting tape were investigated using acoustic emission (AE) technique at room temperature. The tensile behavior of Nb 3 Sn-based composite superconducting tape was analyzed using the AE parameters including amplitude, duration time, and event count, which are representative of various deformation parameters such as elasticity, yielding, and cracking. The results show that the AE technique is very effective for evaluating the deformation behavior of Nb 3 Sn-based composite superconducting tape.