An Advanced Ternary Nb3Sn with ZrO2 Precipitates Via the PIT Process

79756S High Energy Physics requires the development of superconducting wires for use in magnets generating fields greater than 15 tesla for applications in areas like the planned interaction-region quadrupoles for the Large Hadron Collider (LHC) luminosity upgrade. Niobium-tin conductors are currently meeting the requirements of the accelerator magnet community, and the powder-in-tube (PIT) processing method holds the promise of meeting the critical current and effective filament size targets simultaneously. This project seeks to increase the critical current density in PIT Nb3Sn conductors. The approach is to fabricate ternary Nb3Sn with zirconium oxide pinning centers to limit grain growth. The Zr will allow higher diffusion heat treatment temperatures to be used without excessive grain growth, achieve more uniform tin distribution in the superconducting layer, and result in higher upper critical field and critical temperature. In Phase I, Nb1Zr tubes will be manufactured with Nb47Ti layers added to serve as the Ti source for dopants. The tubes will be fabricated into multifilamentary wires and then heat treated under a range of time and temperature conditions. Scanning electron microscopy will be used to determine the extent of reaction, Sn composition, and grain size. Superconducting performance will be characterized at 4.2K in fields upto 15T tesla. Commercial Applications and Other Benefits as described by the awardee: A high performance, lower cost superconductor should find primary application in accelerators for high energy physics and magnetic confinement fusion systems. The conductor also should find application in high field nuclear magnetic resonance systems, to take advantage of the high upper critical field, and magnetic resonance imaging, to take advantage of the high critical temperature.