The cabling of MgB2 hollow wires by react and wind process

Several architectures of superconducting MgB2 multiwires cables have been manufactured in order to test the viability of a "React & Wind" process, to be used to build large superconducting magnets or high current transport cables and busbars. Round wire precursors are drawn with an internal Mg core, in order to produce a hollow superconducting phase by the "in situ" Reactive Mg Liquid Infiltration process. The precursor has been drawn to small diameters, of the order of half a millimetre, then it is braided according to various transposition geometries to realize a precursor cable. To obtain the superconducting cable, a final heat treatment is applied batch wise or continuously in a tube furnace. Finally, the cable may be stabilized by cladding it with low melting metals. Both braiding and cabling operations are done taking into account the mechanical characteristics of the wires and assuming a safety margin in the applied flexural strains. The transport superconducting properties of the cables are measured at different temperatures and magnetic fields and, in some cases, are checked also after small mechanical deformations of the cables. The deformation analysis is intended to determine the limiting strains that these superconducting cables can sustain.