TY - JOUR
T1 - The Role of Hydrogen on the Local Fracture Toughness Properties of 7XXX Aluminum Alloys
AU - Bhuiyan, Md Shahnewaz
AU - Toda, Hiroyuki
AU - Shimizu, Kazuyuki
AU - Su, Hang
AU - Uesugi, Kentaro
AU - Takeuchi, Akihisa
AU - Watanabe, Yoshio
N1 - Funding Information:
The synchrotron radiation experiments were performed with the approval of JASRI through Proposal No.2013B1324, 2014A1018, and 2014B1157. This work was undertaken as a part of Development of Innovative Aluminum Materials Projects and Technological Development of Innovative New Structural Materials with the Project Code HAJJ262715. The authors also appreciate the financial assistance of the Light Metals Education Foundation.
Funding Information:
The synchrotron radiation experiments were performed with the approval of JASRI through Proposal No.2013B1324, 2014A1018, and 2014B1157. This work was undertaken as a part of Development of Innovative Aluminum Materials Projects and Technological Development of Innovative New Structural Materials with the Project Code HAJJ262715. The authors also appreciate the financial assistance of the Light Metals Education Foundation. Manuscript submitted October 18, 2017.
Publisher Copyright:
© 2018, The Minerals, Metals & Materials Society and ASM International.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - 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.
AB - 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.
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U2 - 10.1007/s11661-018-4880-0
DO - 10.1007/s11661-018-4880-0
M3 - Article
AN - SCOPUS:85053028703
SN - 1073-5623
VL - 49
SP - 5368
EP - 5381
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
IS - 11
ER -