| Budget Amount *help |
¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2011: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Outline of Final Research Achievements |
The bronze-processed Nb3Sn wires are being used for the high field magnet applications. A tin content in bronze alloys is probably the most effective approach for increasing the critical current density and it affects the mechanical property and workability of bronze billets. The maximum solubility of tin in the ductile copper (alpha phase) is 15.8 mass% around 550 oC. An increasing of tin content over solubility limit creates the coarse delta phase, which is quite hard and brittle intermetallic compound. In this study, the new high tin bronze alloys having 18.5 mass%Sn have been developted. It shows a good elongation of nearly 10 % at room temperature. The coarse delta phase disappeared perfectly with appropriate Ti addition, and they replaced finer Cu-Sn-Ti ternary precipitates. In addition, multifilamentary wires were successfully fabricated. Nb3Sn layer Jc (4.2K, 12T) was 2800-3000 A/mm2, which was 1.5 times higher than that for the wire used 16 mass%Sn bronze.
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