Effect of Tensile Stress on the Transition Temperature and Current-Carrying Capacity of Nb3Sn

The effect of a uniaxial tensile stress on the superconducting properties of a Nb3Sn-cored wire has been measured. The critical temperatures based on the midpoint of the resistance-temperature curves, decrease with increasing applied stress for a niobium-sheathed wire, while the critical temperature first increases and then decreases for a Monel-niobium-sheathed wire. In the Monel-sheathed wire the initial increase in critical temperature is probably due to the fact that the Nb3Sn is under compression. The current-carrying capacities of both types of wire first increase, then decrease on application of stress. As much as 10% of the zero-stress critical-current value can be lost under tension and still be recovered on unloading.