Ga Doping Enables Precision Alloy‐to‐Wire Regulation: Synergistic Enhancement of the Mechanical Properties of CuSn Alloy and the Superconducting Properties of Nb ₃ Sn

Cu-Sn alloy is a key raw material used in the preparation of Nb₃Sn superconducting wires using the bronze method. The mechanical properties of this Cu-Sn alloy are directly responsible for determining the properties of the superconducting wires. The superconducting properties of Nb₃Sn can be significantly improved by Ga doping. However, the effect of Ga doping and the amount thereof on the properties of Cu-Sn alloys has rarely been reported. In this study, the distribution of Ga and its impact on the mechanical properties of Cu-Sn alloys are investigated via experiments and simulations. The results indicate that Cu and Ga readily produce strong electron exchange and a stable solid-solution structure, leading to Ga superiority in the solid-solution competition with Sn and to δ phase segregation. For the first time, a 1.0 wt.% Ga-added Cu-Sn alloy exhibiting an excellent elongation of 100.8% was successfully prepared. Further investigation revealed that with increasing Ga content, the activation of planar fault slip systems becomes more difficult, the volume fraction of planar fault structures gradually decreases, and the dislocation dissociation distance decreases as cross-slip occurs. The simulation results revealed that as Ga doping increases, the matrix stacking fault energy increases and the deformation mechanism shifts from being dominated by twinning to a balanced combination of slip and twinning, which is the primary mechanism for the synergistic enhancement of strength and ductility in the alloy. In addition, Ga doping significantly elevated the superconducting transition temperature of Nb₃Sn by approximately 0.85 K and improved the critical current density. This study innovatively demonstrates that compared to the front-end Cu-Sn alloy, the addition of 1.0 wt.% Ga achieves synergistic property enhancement of the back-end Nb₃Sn superconducting wire. This study provides both a theoretical and experimental foundation for the preparation of Cu-Sn alloys with elevated properties for use in Nb₃Sn superconducting wires.