SEM study of cracks evolution versus room temperature multiple bending treatment of Nb3Sn wires

SEM study of cracks evolution versus room temperature multiple bending treatment of Nb3Sn wires

Badica Petre，淡路智，小黒英俊，西島元，渡辺和雄（東北大）
p.badica*imr.tohoku.ac.jp
Abstract:　 Multiple bending at room temperature （’pre-bending effect’） of practical Nb3Sn wires is known to be useful in enhancement of superconducting characteristics through relaxation of the residual strain induced during wire processing. On the other side， depending on wire architecture， materials and pre-bending parameters such as pre-bending strain epb， and number of bending cycles， cracks form and develop ultimately resulting in degradation of the superconducting functional parameters of the wire. Our presentation will focus on SEM observations and analysis of the cracks evolution for different pre-bending conditions and types of wires， targeting a better understanding of the relationship pre-bending - cracks - properties.