| Project/Area Number |
08650097
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Materials/Mechanics of materials
|
|---|
| Research Institution | Nagaoka University of Technology |
|---|
Principal Investigator |
OKAZAKI Masakazu Nagaoka University of Technology, Dept.Mech.Eng., Associate Professor, 工学部, 助教授 (00134974)
|
|---|
| Project Period (FY) |
1996 – 1997
|
| Project Status |
Completed (Fiscal Year 1997)
|
| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1997: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1996: ¥2,100,000 (Direct Cost: ¥2,100,000)
|
|---|
| Keywords | Diffusion bonding / Bonding Pressure / Oxide dispersion strengthened Ni-base alloy / Secondary recrystallization treatments / Longitudinal joints / Transverse joints / Optimization / High temperature fatigue strength / L方向接合体 |
|---|
| Research Abstract |
Diffusion bondings of an oxide dispersion strengthened Ni-base alloy, MA758 was studied, combining and controlling some bonding parameters and the microstructures. The high temperature fatigue strength of the joints optimized was also investigated, compared with those of base materials.
The conclusion reached are sumarized as follows :
(1) The post weld recrystallization treatment was found to be essential to improve the properties of the joints at high temperatures.
(2) There is the best bonding pressure to obtain good joint : When the diffusion bondeing pressure was too low, non-bonded region remained. On the other hand, when it was too high, a non-recrystallized region with inadequately growing grains was retained at the welded interface, which reduced the mechanical properties of the joints.
(3) The FEM analysis indicated that the retained non-recrystallized region show in the conclusion
(2), must be resulted from the too large plastic deformation which would take away internal strain energy for adequate grain growth from the material. The shape of bonding component to avoid the retained non-recrystallized region was improved and proposed. The joints produced by employing the improved geometry and the optimum welding condition, revealed the fatigue strength almost comparable to that of the base material.
|
