| Project/Area Number |
09650767
|
|---|
| 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 INSTITUTE OF TECHNOLOGY |
|---|
Principal Investigator |
TAKASHIMA Kazuki Precision and Intelligence Laboratory, Tokyo Institute of Technology, 精密工学研究所, 助教授 (60163193)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TONDA Hideki Faculty of Engineering, Kumamoto University, 工学部, 教授 (90040386)
SHIMOJO Masayuki Precision and Intelligence Laboratory, Tokyo Institute of Technology, 精密工学研究所, 助手 (00242313)
HIGO Yakichi Precision and Intelligence Laboratory, Tokyo Institute of Technology, 精密工学研究所, 教授 (30016802)
|
|---|
| Project Period (FY) |
1997 – 1998
|
| Project Status |
Completed (Fiscal Year 1998)
|
| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1997: ¥2,500,000 (Direct Cost: ¥2,500,000)
|
|---|
| Keywords | Titanium / Single Crystal / Fatigue / Crystallographic Orientation / Crack Growth Rate / Crack Growth Mechanism / Slip System / Twinning |
|---|
| Research Abstract |
The fatigue crack growth behavior of alpha-titanium single crystals has been investigated in laboratory air at room temperature. Six types of CT specimens A, B, C, D, E and F with different notch orientations were prepared. The notch plane and direction in the A-specimen were (1210) and [1010], and those in the B-specimen were (0110) and [2110], respectively. The notch plane of the C-specimen was (0110) and that of the D-specimen was (1210), and the notch direction of both the C- and the D-specimens was [0001], In the E- and the F-specimens, the notch plane was (0001), and the notch directions were [1010] and [2110], respectively. The crack in the A- and the B-specimens propagates parallel to (0110) [2110]. Therefore, the crack is deduced to extend by alternating shear on two intersecting prismatic slip systems at the crack tip. The crack in the C- and the D-specimens propagates close to the basal plane which is perpendicular to the notch directions. This indicates that the fatigue crack is difficult to grow along [0001] compared with parallel to the basal plane. In the E- and the F-specimens, the crack propagates roughly parallel to the basal plane and the traces which correspond to {1012} twin systems are found near the crack plane. Ridges parallel to <1010>, and traces and bands due to {1012} twinning are observed on the fatigue surfaces. These results suggest that the crack growth might occur plausibly by the activation of micro-twins. A definite crystallographic dependence of fatigue crack growth behavior in alpha-titanium is obtained.
|
