Superconducting and Mechanical Properties of RE-Ba-Cu-O/Ag Bulk Superconductors

Abstract

Melt-processed REBaCuO (RE: rare earth) superconductors have a high at 77 K and a high magnetic field, which are expected to be used for high field applications such as superconducting permanent magnets with liquid nitrogen refrigeration, flywheels, current leads and so on. In this study, we discuss Ag-doped YBaCuO and SmBaCuO bulks melt-processed in air and their characteristic superconducting and mechanical properties. Isothermal undercooling growth in air with oxygen annealing and the Nd123/MgO thin film cold seeding technique were applied to seek a highly efficient process, homogeneity of composition, and feasibility of batch production. Single-domain growth of superconducting phases was achieved. The results of mechanical properties, e.g. flexural stress of REBaCuO bulk superconductors show the beneficial effect of Ag particles in the RE123 superconducting phase on strengthening and toughening the material. The results imply that the melt process is feasible for producing larger bulks in large-scale applications. Applications of superconducting technology to railways are also discussed.Index Terms-Flexural stress, melt process, REBaCuO high-temperature superconductors, trapped magnetic field.

Mechanical Properties of<tex>$rm Y$</tex>123/<tex>$rm Ag$</tex>Superconducting Bulks

“…The results show the beneficial effect of particles in the 123 superconducting phase [12]- [14] on strengthening and toughening the material.…”

Stress–strain behavior under static loading in Gd123 high-temperature superconductors at 77K

“…Microstructures of RE123 melt-processed bulks and those of RE123 materials of HTS conductors are similar to each other in that both of them have single-grained matrices, although the composition and size of the secondary phase are different from each other [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. For example, melt-processed bulks consist of RE123 matrix and RE 2 BaCuO 5 (RE211) secondary phase particles.…”

Preparation and Mechanical Properties of Large Single Domain DyBaCuO Superconductor

“…As an amount of Ag addition increases, the porosity in volume fraction of the samples decreases linearly. The results showed the beneficial effect of Ag particles in the Y-123 superconducting phase [11], [12] on strengthening and toughening the material. Ag particles in the Y-123 phase improve microstructures due to reduction of pores and cracks in size and numbers, and the existence of Ag produces the compressive stress field in the Y-123 matrix.…”

“…Mechanical properties in high-superconductors are very crucial, as well as , and for industrial applications [7]- [12]. Mechanical properties would include tensile strength, compressive strength, flexural stress, fracture toughness, elasticity, surface roughness, density, porosity, hardness and fatigue of bulk superconductors.…”