A versatile facility for investigating field-dependent and mechanical properties of superconducting wires and tapes under cryogenic-electro-magnetic multifields.

To investigate the field-dependent and mechanical properties of superconducting wires and tapes as a function of cryogenic temperature, transport current, and magnetic field, we designed and constructed a versatile facility capable of providing cryogenic-electro-magnetic multifields. The facility comprises several relatively independent systems to acquire multiple fields and explore various properties for superconductors. A superconducting racetrack magnet is manufactured to generate a transverse background field up to 3.5 T in a relatively large space of a homogeneous region of ∅200 mm × H 150 mm. A cryogenic system consisting of a vacuum Dewar vessel with a visible window cooled by two Gifford-McMahon (GM) cryocoolers for providing refrigeration was built to accommodate the background magnet and testing devices, in which one GM cryocooler cools the magnet at an operation temperature of about 4 K and the other maintains a cryogenic environment for specimens in conduction mode with the cryocooler head directly contacting the fixtures. The continuous variations of temperature (4-293 K) and transport current (0-1000 A) in the superconducting wires and tapes that were tested are, respectively, implemented by an integration differentiation temperature control with an optional temperature sweep rate and a DC high-power supply. Most prominently, the facility can measure the field-dependent and mechanical properties for superconducting wires and tapes, which is implemented by a mechanical loading and measuring system equipped with a universal testing machine possessing a specific design of widening and heightening size and a noncontact digital image correlation method with a high-speed, high-resolution CCD camera for real-time recording and full-field deformation of specimens. The preliminary results of tests verify the multifield functionalities of the versatile facility and illustrate the performance of the facility for studying the properties of superconducting wires and tapes as a function of magnetic field, cryogenic temperature, transport current, and mechanical loading.