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The effects of cyclic and static transverse stress on the critical current of Ya-Ba-Cu-O coated tapes made using ion-beam-assisted deposition at 76K in self magnetic field are measured.

A Nb tape with 1.4 wt% ZrO2 precipitates were used to prepare tensile test specimens for modulus of elasticity tensile measurements at 4 K and room temperature. Results reveal a low temperature softening at the elastic modulus. The values were consistent with those derived in previous studies employing vibrating reed, ultrasonic and static beam deflection measurement techniques.

Experiments are performed to determine the effect of a varying magnetic field orientation on the critical current density of high temperature superconductor coils and multifilamentary conductors. Results suggest that the magnetic field causes the end turns of a superconductor magnet winding to limit the critical current. The data also indicates that the effect of angle dominates the effect of reduced flux density at the magnet ends.

The quenching behavior and fatigue degradation characteristics of a Cu- and an Al/Cu-stabilized NbTi superconducting coil at four Kelvin and five Kelvin were investigated. According to resistivity-fatigue, room temperature annealing and stability measurements, high purity aluminum is a better stabilizer than copper in fiberglass-epoxy-impregnated coils. It enables higher magnetic fields and reduced magnet size without a tradeoff in stability.

The development of a high resolution high-field 1 GHz NMR spectrometer has been undertaken by Battelle Pacific Northwest Laboratories (BPNL). In preparation for the design of the superconducting magnet for that instrument, BPNL sponsored a program to measure the properties at high field (up to 23.5 T) and low temperature (1.8 K) of a number of commercially available superconductors. Lengths of these conductors were obtained and tested as short samples and in small coils. The critical current densities, index values and strain dependence of these properties were characterized. The potential applications of these conductors in construction of a 1 GHz NMR magnet are discussed.

Changes in the critical current of multifilamentary Nb3A1 superconducting wires due to transverse compressive stress and axial tensile stress were examined. Measurements of the two stress effects on Nb3Al were compared to to the commercially available Nb3Sn wires by using the estimates of the first elastic-modulus of Nb3Al exposed to cryogenic temperature. Relative insensitivity to stress was exhibited by the Nb3Al conductors.

The effect of transverse stress is measured on the critical current of two similar sets of Bi-2223 tapes in direct comparison between tapes reinforced with pure Ag and oxide-dispersion-strengthened Ag. In one case for each sample type, the degradation was significantly greater, and there was an apparent correlation with porosity in the superconductor filaments.