Thermal conductivities and thermal runaways of superconducting MgB₂ wires stabilized by an Al + Al₂O₃ sheath

Abstract

This paper presents a study of the thermal transport properties of extra-light MgB2/Ti/Al + Al2O3 composite wires. The longitudinal thermal conductivity has been investigated as a function of temperature and magnetic field on wires differing only by an outer Al + Al2O3 sheath. The correlation between the thermal transport properties, the microstructure of the Al + Al2O3 sheath and the Al/Ti interface reactions provide important information for these thermally stabilized extra-light superconductors. The thermal runaways observed by the current–voltage characteristics of MgB2/Ti/Al + Al2O3 wires correlate well with the conductor’s temperature affected by the thermal conductivity and the resistance of the outer sheath.