Strong no-barrier SS sheathed MgB2 composite wire

Abstract No barrier MgB 2 /SS composite wire was fabricated by the powder-in-tube (PIT) and by the internal magnesium diffusion (IMD) into boron process. Mechanically strong SS sheath keeps the high density of boron powder during could wire drawing, which allows the creation of dense MgB 2 layer. Only weak interaction has been found at the MgB 2 /SS interface after the final heat treatment at 650 °C/30 min. Measured critical currents at external field and at tensile stress have shown high engineering current density and excellent stress tolerance of MgB 2 /SS sheathed wire made by IMD process.