| Budget Amount *help |
¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000)
Fiscal Year 2017: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2016: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2015: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
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| Outline of Final Research Achievements |
In this study, we aimed to fabricate an age-hardened Cu-Ni-Sn alloy with a high strength, an excellent stress relaxation resistance and a suitable conductivity. A Cu-9wt%Ni-9wt%Sn alloy with proposed compositions of Ni and Sn, and Cu-9wt%Ni-6wt%Sn, Cu-15wt%Ni-8wt%Sn, and Cu-21wt%Ni-5.5wt%Sn alloys with almost the same compositions of Ni and Sn as commercial Cu-Ni-Sn alloys were first peak-aged at 400°C, then cold-rolled, and finally annealed at 400°C to improve the stress relaxation resistance of the four cold-rolled alloys. This thermomechanical heat treatment is the author's unique method. The four alloys have tensile strengths higher than those of commercially available alloys by about 100 to 200 MPa, and their conductivities are comparable, but their resistances to stress relaxation are smaller. Among the four alloys, the balance of strength, stress relaxation resistance, and conductivity of the Cu-9%Ni-9%Sn alloy is the most excellent.
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