| Project/Area Number |
13450046
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Materials/Mechanics of materials
|
|---|
| Research Institution | KYOTO UNIVERSITY |
|---|
Principal Investigator |
KOMAI Kenjiro Graduate School of Eng., Dept. Mech. Eng., Professor, 工学研究科, 教授 (70025948)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TANAKA Kazuto Graduate School of Eng., Dept. Mech. Eng., Research Associate, 工学研究科, 助手 (50303855)
MINOSHIMA Kohji Graduate School of Eng., Dept. Mech. Eng., Associate Professor, 工学研究科, 助教授 (50174107)
|
|---|
| Project Period (FY) |
2001 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
|
| Budget Amount *help |
¥17,300,000 (Direct Cost: ¥17,300,000)
Fiscal Year 2002: ¥4,900,000 (Direct Cost: ¥4,900,000)
Fiscal Year 2001: ¥12,400,000 (Direct Cost: ¥12,400,000)
|
|---|
| Keywords | Environmental Strength / Hydrogen Embrittlement / Stress Corrosion Cracking / Localized Hydrogen Distribution / Cyclic and Dynamic SCC / High-Strength Steel / Thermal Desorption Analyses of Hydrogen / Environmental Strength under Dynamic Loading Conditions / 昇温水素分析 / 繰返し応力腐食割れ |
|---|
| Research Abstract |
Advanced metallic materials are sensitive to an environment and in order to clarify the degradation mechanisms and to improve the toughness of the metallic materials in a service environment, we must clarify the process of hydrogen entry as well as the hydrogen trap sites in the material. In this research project, a method to analyze the localized hydrogen distribution has been developed: the method is based upon a silver decoration technique. The investigation yields the following conclusions, i) An amount of silver precipitated on a sample is increased with an increase in a hydrogen content of the test sample, ii) The sensitivity of the method is increased with a decrease in the pH value of the decoration solution, iii) A small particle of silver on the sample surface can be analyzed by a kind of a Kelvin force microscope. iV) The sensitivity of the method is extremely improved by coating a kind of metallic thin film on the sample surface. The important thing is the correlation betwe
… More
en the hydrogen content and the amount of the precipitated silver on the sample surface. For this purpose, the hydrogen was charged from the one side of the sample, and the hydrogen which passed through the sample was detected on the other side of the sample. This shows a good agreement between the permeated hydrogen current or the hydrogen content of the sample and the amount of precipitated silver on the sample surface. This means that the developed method is useful to analyze the hydrogen distribution in a quantitative manner. The investigation also includes the evaluation of the environmental strength of a high-strength steel: the crack growth rate is increased under a cathodically charged condition, and the fracture surface became transgranular. The analyses of the localized hydrogen distribution as well as the thermal desorption behavior of hydrogen show that the charged hydrogen is mainly absorbed within a grain, and this agrees with the fracture surface morphology. Moreover, in situ AFM analyses of a growing stress corrosion crack show that the growth behavior is dependent on the localized hydrogen distribution, and this caused an acceleration and retardation of a stress corrosion crack growth. Less
|
