TY - JOUR
T1 - Effects of overload mode-mixity on fatigue damage behavior and governing micromechanisms in AA7075 under biaxial fatigue loading
AU - Singh, Abhay K.
AU - Datta, Siddhant
AU - Chattopadhyay, Aditi
AU - Phan, Nam
N1 - Funding Information:
The research is sponsored by the U.S. Navy Naval Air Systems Command through Cooperative Agreement P-8A Aircraft Support for PMA-290, Program Manager Nam Phan.
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/4
Y1 - 2021/4
N2 - An investigation into the effects of overload mode-mixity on crack growth behavior and governing micromechanisms of AA7075 T6 has been conducted. Cruciform AA7075 T6 specimens were subjected to constant amplitude planar biaxial fatigue with single overloads, and key fatigue damage behavior, including fatigue life, crack growth rate, and recovery distance, were investigated and correlated to overload parameters. Additionally, SEM fractography was conducted to identify and relate fracture surface features to governing fatigue damage micromechanisms. An increase in fatigue life was observed for all cases of mode-mixity, with the minimum increase occurring at 45°. The mix-mode overloads also caused crack retardation in all cases. In the shear dominant overloads, however, initial post-overload crack acceleration occurred and was immediately followed by crack retardation. Microscale analysis showed distinct fracture features in the pre-overload, transient, and post-overload regions for both tensile and shear dominant overloads.
AB - An investigation into the effects of overload mode-mixity on crack growth behavior and governing micromechanisms of AA7075 T6 has been conducted. Cruciform AA7075 T6 specimens were subjected to constant amplitude planar biaxial fatigue with single overloads, and key fatigue damage behavior, including fatigue life, crack growth rate, and recovery distance, were investigated and correlated to overload parameters. Additionally, SEM fractography was conducted to identify and relate fracture surface features to governing fatigue damage micromechanisms. An increase in fatigue life was observed for all cases of mode-mixity, with the minimum increase occurring at 45°. The mix-mode overloads also caused crack retardation in all cases. In the shear dominant overloads, however, initial post-overload crack acceleration occurred and was immediately followed by crack retardation. Microscale analysis showed distinct fracture features in the pre-overload, transient, and post-overload regions for both tensile and shear dominant overloads.
KW - Biaxial fatigue
KW - Crack propagation
KW - Fatigue life
KW - Fractography
KW - Mix-mode overload
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U2 - 10.1016/j.ijfatigue.2021.106141
DO - 10.1016/j.ijfatigue.2021.106141
M3 - Article
AN - SCOPUS:85099257762
SN - 0142-1123
VL - 145
JO - International Journal of Fatigue
JF - International Journal of Fatigue
M1 - 106141
ER -