METALLURGICALLY ENGINEERED NB3SN SUPERCONDUCTING WIRE WITH HIGH JC

THE FORMATION OF HOMOGENEOUS NB3SN REACTION LAYERS DURING REACTION HEAT TREATMENTS IS LIMITED BY THE SN DIFFUSION THROUGH THE NB3SN LAYER. IT HAS BEEN SHOWN THAT TI ADDITIONS INCREASE THE DIFFUSION RATES OF SN THROUGH NB3SN. TI-DOPED NB3SN HAS EXCELLENT HIGH FIELD PROPERTIES DUE TO INCREASED UPPER CRITICAL FIELD (HC2); HOWEVER THE LOWER FIELD PROPERTIES ARE DECREASED DUE TO EXCESSIVE GRAIN GROWTH. THIS PROJECT WILL FABRICATE NB3SN MATERIALS USING THE CONVENTIONAL BRONZE-ROUTE PROCESS. THE MONOFILAMENT CORES WILL CONSIST OF TI-DOPED NB AROUND A NB CENTRAL CORE. THIS WILL PRODUCE A MORE UNIFORM NB3SN REACTION LAYER BY PROVIDING A HIGH SN DIFFUSION RATE IN THE OUTER REGIONS OF THE MONOFILAMENT. THIS WILL GREATLY ENHANCE THE MEDIUM FIELD PROPERTIES OF THE SUPERCONDUCTOR BY ALLOWING SUBSTANTIALLY REDUCED REACTION HEAT TREATMENT TEMPERATURES.