Characterisation of the Mechanical Behaviour of Superconducting Cables Used in High Field Magnets From Room Temperature Down to 77K

A comprehensive knowledge of the mechanical properties of the superconducting cable used in high-field magnets is of paramount importance to study and model the behaviour of the magnet coil from assembly to the operational conditions at cryogenic temperature. The mechanical characterisation of such kind of materials presents practical challenges associated with the heterogeneity of the materials, the geometry, size and quality of the samples that can be produced out of actual cables. These constraints impose the undertaking of such measurements from a nonstandard approach, and hence the development of tailor-made tooling. An extensive characterisation campaign for the determination of the mechanical properties of the superconducting cable at room and cryogenic temperature was launched at CERN in order to determine the most relevant mechanical properties of the superconducting cables used in the MQXF and 11T magnets. This paper describes the design of the tooling developed for this specific application as well as the experimental set-up used for the tests, and discusses the outcomes of the matrix of tests performed.