2005 Fiscal Year Final Research Report Summary
Failure at cooled internal webs in Ni-based superalloy single crystals blades
| Project/Area Number |
16560613
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Structural/Functional materials
|
|---|
| Research Institution | Tokyo Metropolitan University (2005)
Tokyo Metropolitan Institute of Technology (2004) |
|---|
Principal Investigator |
KAKEHI Koji Tokyo Metropolitan University, Dept. of Mechanical Engineering, Associate Professor, 都市教養学部, 助教授 (70185726)
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Keywords | Superalloy / Single Crystals / Gas Turbine Blade / Creep / Internal Cooled webs / Mechanical twinning / Anisotropy |
|---|
| Research Abstract |
As the performance of alloys at the crucial intermediate temperature range has improved with the addition of rhenium, it has become apparent anecdotally that there is a significant increase in the primary creep observed at lower temperatures. In cooled blades the internal webs, which bear the majority of the load, can operate at temperatures as low as 700℃. However no systematic study of the effect of rhenium on the creep performance at low (750℃-850℃) temperatures and in particular on the extent of primary creep has been undertaken. It has been found that the amount of primary creep increases as the amounts of rhenium and cobalt in the alloys increase, and for each alloy a stress threshold for the occurrence of a distinct regime of primary creep is identified. TEM observations of the dislocation mechanism of deformation show a higher occurrence of stacking fault shear with increasing primary creep. Considerable differences in the extent of dislocation penetration into the γ phase and in the configuration of the mobile dislocation ribbons point to a combination of factors governing mobility and hardening being responsible for high primary creep.
|
