In situ strain measurements of Bi2223 superconducting filaments in multifilamentary Ag-sheathed Bi2223 superconducting tapes

Thermally and mechanically induced residual strain and strain tolerance of critical current in stainless steel-laminated Bi2223/Ag/Ag alloy composite superconductors

“…Step 2 (T1 → RT(1)) Upon further cooling of the insert tape from T1 (495 K) to room temperature 293 K (RT(1) in figure 3), Ag deforms plastically in tension. The change of strain of each constituent from T1 to RT, ε i,T1→RT (i = Bi2223 and Ag alloy), is calculated by equation (14). The elastic strain of Ag does not change from T1 to RT(1), being equal to +ε Ag,y .…”

In situ strain measurements of superconducting composites by depth and layer sensitive X-ray diffraction technique utilizing synchrotron radiation

“…In such a case, it is also necessary to pursue technical possibility of assessing the strain of each layers separately, since the important point is the strain in the superconducting layer. In the present work, DyBa2Cu3O6+ In-plane measurement has a merit that the axial strain is directly detected, whereas the measurement using reflection (Bragg) geometry suffers from low Poisson's ratio of about 10 to 20% [11,12], which makes the detection of small strain quite difficult, in particular, for the tensile case where the fracture strain is much lower than the compression case [2,5], but technically important.…”

“…The average parameters obtained from macroscopic mechanical tests or thermal measurements sometimes turned out to be inadequate to understand local degradation processes, and sometimes the contribution of the superconducting layer of interest to the overall mechanical signal was too small for separate analysis. We have demonstrated that by choosing photon energy to have a good balance between transmission and resolution, it is possible to evaluate the strain of superconducting oxides in-situ during tensile [5][6][7] or bending [8] deformations at ambient temperatures.…”

“…Owing to recent developments of Dy-based high-perfomance coated superconducting tapes [9], importance of in-situ measurements of strain for such coated materials has been also increasing. Technically, it is difficult to measure the axial strain of coated materials in the same transmission geometry as reported for the Bi2223 case [5][6][7], because of very thin oxide layer and relatively thick Hastelloy substrate.…”

Assessment of strain of Bi2223 filaments in bent Ag-sheathed superconducting composites by synchrotron radiation

“…Therefore, the effects of applied strains as well as thermal residual strains introduced during fabrication have been discussed by many researchers [1]- [3]. In the recent experiments, we performed in-situ measurement of axial strain in Ag-sheathed Bi2223 superconducting composite with and without stainless steel lamination in Laue geometry at room temperature [4,5]. The results clearly showed the strain of Bi2223 filaments changing from residual compressive strain to eventually multiple fracture state on tensile deformation.…”