Impact of Transverse Compression on the Sub-Element RRP Nb3Sn Strand

For developing a 14 Tesla whole-body superconducting magnetic resonance imaging (MRI) magnet, a new kind of a Nb
₃
Sn composite conductor with Rutherford cable-in-channel (RIC) structure is adopted. This structure of the conductor has a high current carrying capacity with an increased thermal and mechanical stability. The Rutherford cable is the core component of the RIC conductor, and controlling the deformation and performance degradation of Nb
₃
Sn strand are the key points in Rutherford cable development. The strand would experience plastic deformation during the compaction process, which causes sub-elements damage and degrades the transport performance and residual resistivity ratio (RRR). In this paper, the impact of transverse compression on the sub-element of RRP 84/91 Nb
₃
Sn strand before heat treatment was studied with experiments and finite element model (FEM), the experiment results and FEM results were compared and analyzed. Experiment results show that the transverse deformation of the strand should be kept below 20% to avoid the Nb barrier from breaking. The deformation analysis result of the FEM simulation shows good agreement with experimental results.