TY - JOUR
T1 - Distinct fatigue limit of a 6XXX series aluminum alloy in relation to crack tip strain-aging
AU - Takahashi, Yoshimasa
AU - Kuriki, Ryosuke
AU - Kurihara, Jun
AU - Kozawa, Tomoyuki
AU - Shikama, Takahiro
AU - Noguchi, Hiroshi
N1 - Funding Information:
The authors are indebted to Mr. M. Kashihara and Mr. W. Takahashi (Kansai University) for their help with fatigue experiments. This study was financially supported in part by the Kansai University Grant-in-Aid for progress of research in graduate course (2017), Kansai University Expenditures for Support of Training Young Scholars (2017–2018) and JSPS KAKENHI No. 18H01344 . Y. T. of the authors is also grateful to financial support by the Kansai University Fund for Domestic and Overseas Research Fund, 2019.
Funding Information:
The authors are indebted to Mr. M. Kashihara and Mr. W. Takahashi (Kansai University) for their help with fatigue experiments. This study was financially supported in part by the Kansai University Grant-in-Aid for progress of research in graduate course (2017), Kansai University Expenditures for Support of Training Young Scholars (2017?2018) and JSPS KAKENHI No. 18H01344. Y. T. of the authors is also grateful to financial support by the Kansai University Fund for Domestic and Overseas Research Fund, 2019.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/5/21
Y1 - 2020/5/21
N2 - In this study, a conventional precipitation-hardened A6061-T6 alloy (base alloy) and a modified alloy containing excess solute magnesium (Mg) compared to the base alloy were compared in terms of high-cycle fatigue property. Particular attention was paid to the emergence of a distinct knee point on the fatigue life diagram together with a time-dependent strengthening (coaxing) effect in the modified alloy under various test conditions. An attempt using specimens with different defect size successfully revealed that a distinct knee, which was absent in the base alloy, was attributed to the threshold against small crack growth. The clear coaxing effect in the modified alloy was also explicitly confirmed in terms of the high ΔK value achieved by the arrested cracks regardless of the defect size. The comparative tests conducted under different environments and temperature conditions further confirmed that the crack tip strengthening, essentially caused by the strain-aging capability endowed to the modified alloy, operated most prominently in the ambient air at room temperature. Such results were rationally interpreted by incorporating a competitive interaction of solute Mg and hydrogen (H) with dislocations at the crack tip.
AB - In this study, a conventional precipitation-hardened A6061-T6 alloy (base alloy) and a modified alloy containing excess solute magnesium (Mg) compared to the base alloy were compared in terms of high-cycle fatigue property. Particular attention was paid to the emergence of a distinct knee point on the fatigue life diagram together with a time-dependent strengthening (coaxing) effect in the modified alloy under various test conditions. An attempt using specimens with different defect size successfully revealed that a distinct knee, which was absent in the base alloy, was attributed to the threshold against small crack growth. The clear coaxing effect in the modified alloy was also explicitly confirmed in terms of the high ΔK value achieved by the arrested cracks regardless of the defect size. The comparative tests conducted under different environments and temperature conditions further confirmed that the crack tip strengthening, essentially caused by the strain-aging capability endowed to the modified alloy, operated most prominently in the ambient air at room temperature. Such results were rationally interpreted by incorporating a competitive interaction of solute Mg and hydrogen (H) with dislocations at the crack tip.
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U2 - 10.1016/j.msea.2020.139378
DO - 10.1016/j.msea.2020.139378
M3 - Article
AN - SCOPUS:85083395486
SN - 0921-5093
VL - 785
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
M1 - 139378
ER -