|About this Abstract
||Materials Science & Technology 2011
||Fatigue and Microstructure: A Symposium on Recent Advances
||Microstructural and Environmental Effects on Fatigue Crack Growth in 7075 Aluminum Alloy
||Aboozar Bonakdar, Jason Williams, Nikhilesh Chawla
|On-Site Speaker (Planned)
The fatigue behavior of aluminum alloys is greatly influenced by environment and precipitate structure. The fatigue crack growth behavior of 7075 Al alloy was investigated. The role of environment was quantified in ultra high vacuum (10-10 torr) as well as in moisture. In this manner, the mechanical and environmental effects were able to be separated. In particular, the role of crystallographic slip, as dictated by precipitate structure, was studied. Rolled 7075 Al alloy was heat-treated to peakaged and overaged conditions. Fatigue crack growth rates were measured under various partial pressures of water vapor. Standard compact tension specimens along the S-T orientation were used, and testing was performed under load ratios of R = 0.1 and R = 0.8. The experimental results were analyzed by a modified Kitagawa approach. The microstructure and morphology of the fracture surfaces were examined by scanning electron microscopy (SEM) and correlated with the crack growth behavior.
||Definite: A CD-only volume