2018年11月1日
The Role of Hydrogen on the Local Fracture Toughness Properties of 7XXX Aluminum Alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
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- 巻
- 49
- 号
- 11
- 開始ページ
- 5368
- 終了ページ
- 5381
- 記述言語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1007/s11661-018-4880-0
High-resolution synchrotron X-ray microtomography has been successfully used to evaluate the local crack driving force at arbitrary crack tip locations as a form of CTOD. This is to our knowledge the first experimental evidence in supporting a correlation between the local fracture toughness associated with the corresponding hydrogen-assisted fracture mode including quasi-cleavage, intergranular, and dimple. Our results have revealed that very small CTOD, of about 1.26 μm, is observed when the crack tip is located in the quasi-cleavage fracture. Compared to quasi-cleavage fracture, the CTOD values increase by a factor of 5 when the crack tip is located in intergranular fracture mode and even greater increase in CTOD (of about 18 times) is observed when the crack tip is located in dimple fracture mode. We also observed that the crack propagation process under the influence of hydrogen deviates greatly from that of standard behavior, where stable crack growth is accompanied by a change in crack tip singularity from the HRR to the RDS. It was concluded that the presence of high concentration of hydrogen ahead of the crack tip increases the slip localization, and thereby reduces crack tip blunting. Hence crack continues to grow before the crack tip becomes fully blunt.
- リンク情報
- ID情報
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- DOI : 10.1007/s11661-018-4880-0
- ISSN : 1073-5623
- ORCIDのPut Code : 57201381
- SCOPUS ID : 85053028703