Study on the Improving the Uniformity of Ti Distribution in New Type of High J_c Nb₃Sn Wire Produced by WST

High J_c Nb₃Sn superconducting wires is mainly used in the preparation of high field magnets because of its higher critical current density. Further improving the critical current density of Nb₃Sn wire, reducing the use amount of wire in magnets is one of important ways to promote the industrialization and mass application of High J_c Nb₃Sn wire. It is known that doping Ti in Nb₃Sn phase can improve the critical magnetic field effectively, refine the Nb₃Sn grains, and improve the critical current density. Too much or too little Ti will greatly reduce the doping effect. The Ti diffusion is later than the Nb₃Sn phase reaction under three-zone section heat treatment, so the distribution of Ti in Nb₃Sn phase is uneven. This paper introduces a new heat treatment process, which can improve the uniformity of Ti in Nb₃Sn phase by adding an insulation platform between the medium temperature and high temperature insulation platform. Eventually, the critical current density of the High J_c Nb₃Sn wire was improved, reaching 2938 A/mm².