Preparation and Mechanical Properties of Large Single Domain GdBaCuO Superconductor With Low Void Density

Abstract

We fabricated large single domain of GdBaCuO (Gd-123) densified superconductor with a seeding and temperature gradient method in oxygen at the melt stage then in air at the growth stage for future applications such as a superconducting flywheel for energy storage system, magnetic separation, and a bulk magnet. The innovative melt-textured single domain of Gd-123 system superconductor was about 46 mm in diameter and 15 mm in thickness. Gd-123 densified superconductors are expected to have high and trapped field properties with higher mechanical strength. We discussed mechanical properties such as the bending stress, the hardness and the surface roughness of the Gd-123 bulk for improving the strength of Gd-123 bulks.

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.…”

Improvement of microstructure and mechanical properties of large single domain GdBaCuO superconductor with low void density

“…Gd 2 BaCuO 5 is homogeneously and finely distributed in both the Gd-123 densified and the standard superconducting matrix Average four-point flexural strength of the specimens in this experiment is 72 MPa for the densified bulk, and 58 MPa for the standard bulk [12]. It is clear that the densified bulk materials show higher flexural strength than the standard bulks with voids; 1.2 times increase by densification of microstructure.…”

“…We prepared two types of Gd-123 bulk; one is a standard bulk, and another is a densified bulk. The standard bulk was heat-treated in air [4], and the densified bulk of which the void density is very low was heat-treated in oxygen at the first melt stage then in air at the second crystal growth stage [12]. We name it a two-step regulated atmosphere heat treatment tentatively.…”

“…The flexural strength of the bulk specimens was measured by the four-point flexure test following JIS-R-1601 at 293 K [12]. We sliced the bulk sample; first made two half size as-grown bulks, then made three blocks for each bulk.…”

Energy and superconductors – applications of high-temperature-superconductors

“…These bulk materials, in particular YBCO, are manufactured as single domain samples via melt-textured-growth [16]. Applications [17] and processing are described elsewhere as levitation is not considered as an application in the energy technology sector.…”