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Production of Jelly-Roll Process Niobium Aluminum Multifilamentary Superconducting Wire Using Warm Hydrostatic Extrusion--Supercon, Inc., 830 Boston Turnpike, Shrewsbury, MA 01545-3301; (508) 842-0174
Mr. Mark K. Rudziak, Principal Investigator
Ms. Elaine Tarkianinen, Business Official
DOE Grant No. DE-FG02-98ER82677
Amount: $600,000
The high-energy physics community requires the development of superconducting wires for use in magnets generating fields in excess of 15T. Nb3Sn is the only commercially available conductor capable of operating at such high fields. Niobium aluminum (Nb3Al) is suited to high field operation, and has superior strain tolerance compared to Nb3Sn, but it is difficult to fabricate in multifilament form. The principal difficulty in fabricating multifilament Nb3Al is obtaining sufficient inter-filament bonding to allow reliable wire drawing. This project will use warm hydrostatic extrusion as a means to bond Nb3 Al multifilament composites sufficiently to allow drawing without excessive breakage. In Phase I, jelly-roll Nb-Al monofilaments were restacked into multifilament billets. Warm (# 300° C) hydrostatic extrusion was utilized to extrude the multifilament billets. Multifilament wire as small as 0.44 mm diameter was successfully fabricated. Reaction heat treatments produced substantial non-copper critical current densities at high field (12T). In Phase II, the processing of Nb-Al jelly-roll multifilaments will be further developed in order to improve fabricability and performance. At the same time, the rapid-quench technique for Nb3Al strand fabrication will be pursued, also using warm hydrostatic extrusion.
Commercial Applications and other Benefits as described by the awardee: High performance Nb3Al conductors should offer a less strain-sensitive alternative to Nb3Sn in magnets for high energy physics particle accelerators and fusion machines. Commercially, such a conductor should find application in nuclear magnetic resonance magnets where Nb3Sn is currently used. The excellent strain tolerance of Nb3Al makes it feasible to use react-and-wind techniques for magnets, offering great cost savings.