| Project/Area Number |
12555209
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 展開研究 |
|---|
| Research Field |
Metal making engineering
|
|---|
| Research Institution | Chiba Institute of Technology |
|---|
Principal Investigator |
MOTOYASU Genjiro Chiba Institute of Technology, Engineering, Professor, 工学部, 教授 (30157846)
|
|---|
| Project Period (FY) |
2000 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥9,600,000 (Direct Cost: ¥9,600,000)
Fiscal Year 2003: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥7,200,000 (Direct Cost: ¥7,200,000)
|
|---|
| Keywords | super-elastic transformations / shape-memory alloy / Cu-Al-Ni / continuous casting / OCC process / single crystal / unidirectional solidification / Al-Ni / 形状記憶 / 連続鋳造法 / 加熱鋳型 / 金属間化合物 / 計上記憶 / 通続鋳浩法 / 一方向凝固組織 |
|---|
| Research Abstract |
The aim of this research is development of soft copper shape-memory, super-elastic alloy material in place of the usual hard Ti-Ni alloy. The copper alloy wire with high rubber elasticity has the possibility to become the useful spring part for the industrial materials.
In this research, the possibility of applying the OCC process to the fabrication of Cu-Al-Ni and Cu-Sn shape memory, super-elastic alloy wires was investigated. It was established that shape memory wires 2 mm in diameter can be continuously cast by OCC process. Cast OCC wires were found to be of single crystal or unidirectional solidified structure with a matrix phase β_1 in which γ_2 particles were precipitated in the form dendrites along the sub-grain boundaries. The γ_2 particles became fewer and the size became finer with an increase in casting speed. The Ms transformation temperature for the Cu-Al-Ni alloy and Cu-Sn alloy was in the range -19℃ to 3℃ and -55℃ to -50℃, respectively, giving rise to super-elastic behavior at the room temperature. The wires cast at slower speeds displayed shape memory attributes on heating to 90℃, whereas the wires produced at higher casting speeds exhibited super elasticity at room temperature. The Cu-Al-Ni alloy wires produced at higher casting speeds exhibited two-step super-elastic transformations as a single crystal wires. In addition, the fatigue failure of the Cu-Al-Ni alloy wires occurred after 25000 bend cycles, which was 10 times that of the conventional Ti-Ni wires. Bending properties of the OCC Cu-Al-Ni alloy wires, such as the softness and the fatigue limit, were superior to those of the conventional Ti-Ni wires.
These findings suggest that the OCC process could be useful for the production of super-elastic single crystal or unidirectional solidified Cu alloy wires.
|
