| Project/Area Number |
11555177
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Structural/Functional materials
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| Research Institution | SHIBAURA INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
OTSUKA Masahisa SHIBAURA INSTITUTE OF TECHNOLOGY, MATERIALS SCIENCE AND ENGINEERING, PROFESSOR, 工学部, 教授 (20013732)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Masami NIHON UNIVERSITY, MECHANICAL ENGINEERING, PROFESSOR, 工学部, 教授 (40156930)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥12,400,000 (Direct Cost: ¥12,400,000)
Fiscal Year 2000: ¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 1999: ¥7,600,000 (Direct Cost: ¥7,600,000)
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| Keywords | lead free solder / mechanical properties / isothermal fatigue / thermal fatigue / Sn-Ag alloy / Cofin-Manson's rule / microjoining / creep / コフィン-マンソン則 |
|---|
| Research Abstract |
Creep characteristics of Sn-3.5%Ag solder alloys in the as-cast state have been investigated in temperature range between 298K and 398K and creep rate range between 1x10^<-8>s^<-1> and 1x10^<-2>s^<-1> with special reference to the effect of third elements. It is found that Sn-3.5%Ag binary alloy shows power-law creep in which stress exponent (n) is about 10 due to the dispersion strengthening effect of Ag_3 Sn particles. The addition of copper up to 2mass% improves the creep strength of Sn-3.5% Ag binary alloy only slightly both at 298K and at 398K.The addition of bismuth up to 10mass% strengthens it considerably at room temperature through the cooperation of dispersion hardening due to Ag_3 Sn and bismuth phases and solution hardening due to solute bismuth atoms, but degrades it in the low stress regime at 398K principally due to the coarsening of bismuth phase during creep.
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