Mechanical-electromagnetic property of stainless sheet laminated BSCCO-2223 wires
ステンレスシートと積層させたBSCCO-2223線材の力学-電磁気的特性
長村 光造*; 町屋 修太郎*; 川崎 卓郎 ; Harjo, S. ; 加藤 武志*; 小林 慎一*; 長部 吾郎*
Osamura, Kozo*; Machiya, Shutaro*; Kawasaki, Takuro; Harjo, S.; Kato, Takeshi*; Kobayashi, Shinichi*; Osabe, Goro*
In order to elucidate the effect of applied tensile stress/strain on the critical current of DI-BSCCO-2223 wires, the critical current measurement and the tensile test were carried out at 77 K. Neutron diffraction measurements were also performed at 77 K to get direct information about the local strain exerted on the BSCCO superconducting filaments. It was reported that the critical current of BSCCO wires decreases linearly in a small range of tensile stress/strain and that the critical current returns reversibly on reducing the stress/strain. The gradual decrease of critical current was observed within the reversible region. When the tensile stress/strain increased beyond a characteristic value, the critical current decreased rapidly due to the brittle fracture of BSCCO filaments. It is proposed that the reversible stress/strain limit of critical current ( and ) can be defined experimentally as the 99% recovery stress ( and strain (. The reversible strain limit is proposed to consist mainly of three factors of pre-strain, thermal strain and tensile fracture strain of SC filaments themselves. The calculated relation between the and could well explain quantitatively the observed relation between 99% recovery stress and strain.