Mechanical Strength Enhancement of the Internal Matrix Reinforced Nb3Sn Multifilamentary Wires Using Cu-Sn-In Ternary Bronze Alloy Matrices by HIP Processing

We are approaching to high mechanical strength of bronze processed Nb₃Sn wire by internal matrix reinforcement using Cu-Sn-In ternary alloy. The In solute element remained homogeneously in the wire matrix after Nb₃Sn synthesis, and it contributed to transforming (Cu, In) solid solutions. And (Cu, In) solid solution acted as the protective material of Nb₃Sn phase and contributed to improving the mechanical strength of the Nb₃Sn wire. In this study, we investigated the Hot Isostatic Press (HIP) treatment on the further mechanical strength improvement of internal matrix reinforced Nb₃Sn wire. Tensile stress and strain sensitivities of transport critical current ($I_{c}$) property were enhanced by HIP processing because many micro-sized vacancies, which were the origin points of the fatigue on the (Cu, In) matrix, were removed. We found the HIP treatment contributes to mechanical strength enhancement of the internal matrix reinforced Nb₃Sn wire.