Development of (Nb,Ta)3Sn multifilamentary superconductor wire for high current applications

Abstract

The optimization of the energy generated by a MagnetoHydroDynamic (MHD) channel using a superconducting magnet demands the optimization of the magnetic field of the system and of the critical points on the magnet winding. This work must include the development of a high performance superconductor wire suitable for this system. Aiming to the construction of improved performance MHD channel, it was developed a low cost superconductor wire, with the required characteristics. The wire was made using a technology compatible with the assembling steps and heat treatment conditions of the MHD superconducting magnets fabrication. It was used the internal Sn method in Nb-7.5wt%Ta tube to fabricate a 271-filament wire with a diameter of 0.81 mm and a Cu/nonCu ratio of 2.3. The wire was heat treated at 200 °C to diffuse the Sn into the Cu shell, producing bronze, followed by the final reaction at temperatures ranging from 670 °C to 730 °C during 25 to 150 h, to produce (Nb,Ta)3Sn. The superconducting wire characterization was made measuring the critical current Ic versus the applied magnetic field in the range of 5 to 20 T, the critical temperature Tc and the residual resistivity ratio (RRR). The wire transported critical currents above those available in commercial superconducting wires. These values of Ic are higher than the expected values for the optimization of the MHD channel

Report on use of Inoculants in Missile Application Alloys

“…Relatively large contents of oxygen in the inoculated melt led to a reduced cell count. SiC particles were added to the molten pool of a high strength low alloy steel (ER110S-G) during WAAM, resulting in grain refinement and the precipitation of Fe3C due to SiC dissociation [105]. The additions improved yield, UTS, and elongation from 681 MPa, 870 MPa, and 39% to 876 MPa, 1070 MPa, and 23%, attributed to the refined grain structures and the dispersed Fe3C particles.…”

COMPARISON OF A15 STOICHIOMETRY AND GRAIN MORPHOLOGY IN INTERNAL Sn AND TUBE TYPE STRANDS; INFLUENCE OF STRAND DESIGN, HTs AND ALLOYING

“…The general idea of tube type conductors, where Cu and Sn are inserted into Nb tubes, has been pursued before [7][8][9][10][11], and these conductors do have some similarities to powderin-tube (PIT) strands (as well as differences) [12][13][14][15][16][17][18][19][20][21]. Early on, geometrically similar conductors were fabricated by Murase and associates [7].…”

“…The phase formation sequence was presumably similar to the present case, but the layer growth and lower J c may indicate a lower Sn level was present in the core. Other groups have studied geometrically similar conductors, including Rodrigues [9] and Yamasaki [8,10]. The conductor described in [9] had 271 filaments and a J c of 680 A/mm 2 at 10 T. The 37 filament conductors studied by Yamasaki [10] reached J c s in the A15 of 6000 A/mm 2 at 9.5 T. However, conductors of the type described below have reached non-Cu J c s of 2440 A/mm 2 at 12 T in strands with 217 filaments [22].…”