Analysis and Modeling of Damage in RRP Nb 3 Sn Wires During Cabling

High-critical current density (J c ) Nb 3 Sn wires such as restacked-rod process wires are used in Rutherford cables for high-field superconducting magnets. However, during cabling, the wires experience strong plastic strains, which break some superconducting sub-elements and can degrade the electromagnetic performances. The damage can be reduced by forming Cu-Sn phases in the sub-elements during an annealing process prior to cabling. We found experimentally that annealing plays a significant role in reducing damage. Furthermore, we used finite-element models to validate the observations on samples and quantify the impact of annealing on damage reduction.