Mechanical properties, interface reactions and transport current densities of multi-core MgB2/Ti/Cu/SS wire

Multi-core MgB 2 / Ti / Cu / SS composite wire has been made by the in situ approach. Mechanical properties, interdiffusion reactions and critical currents were studied after heat treatments at temperatures between 500 and 850 °C. Cu diffusion into the Ti layer occurs for all samples, resulting in the formation of intermetallic compounds at the Cu/Ti interface. EDX analysis has revealed the temperature dependence of all interface reactions. In spite of element reactions the critical current densities 10 5 A cm − 2 and 10 4 A cm − 2 were measured in liquid helium at magnetic fields 5 T and 9.5 T, respectively. 10 4 A cm − 2 at 20 K is measured in an external field of 4 T.